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Valtari A, Posio S, Toropainen E, Balla A, Puranen J, Sadeghi A, Ruponen M, Ranta VP, Vellonen KS, Urtti A, Amo EMD. Comprehensive ocular and systemic pharmacokinetics of dexamethasone after subconjunctival and intravenous injections in rabbits. Eur J Pharm Biopharm 2024; 198:114260. [PMID: 38484852 DOI: 10.1016/j.ejpb.2024.114260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 03/05/2024] [Accepted: 03/11/2024] [Indexed: 04/19/2024]
Abstract
Even though subconjunctival injections are used in clinics, their quantitative pharmacokinetics has not been studied systematically. For this purpose, we evaluated the ocular and plasma pharmacokinetics of subconjunctival dexamethasone in rabbits. Intravenous injection was also given to enable a better understanding of the systemic pharmacokinetics. Dexamethasone concentrations in plasma (after subconjunctival and intravenous injections) and four ocular tissues (iris-ciliary body, aqueous humour, neural retina and vitreous) were analysed using LC-MS/MS. Population pharmacokinetic modelling for plasma data from both injection routes were used, and for first time the constant rate of absorption of dexamethasone from the subconjunctival space into plasma was estimated (ka,plasma = 0.043 min-1, i.e. absorption half-life of 17.3 min). Non-compartmental analysis was used for the ocular data analysis and resulting in ocular drug exposure of iris-ciliary body (AUC0-∞= 41984 min·ng/g) > neural retina (AUC0-∞= 25511 min·ng/g) > vitreous (AUC0-∞= 7319 min·ng/mL) > aqueous humour (AUC0-∞= 6146 min·ng/mL). The absolute bioavailability values after subconjunctival injection, reported for the first time, were 0.74 % in aqueous humour (comparable to topical dexamethasone suspensions), and 0.30 % in vitreous humour (estimated to be higher than in topical administration). These novel and comprehensive pharmacokinetic data provide valuable information on the potential for exploiting this route in ocular drug development for treating both, anterior and posterior segment ocular diseases. Moreover, the new generated dexamethasone-parameters are a step-forward in building predictive pharmacokinetic models to support the design of new subconjunctival dexamethasone formulations, which may sustain drug effect for longer period of time.
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Affiliation(s)
- Annika Valtari
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Susanna Posio
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Elisa Toropainen
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Anusha Balla
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Jooseppi Puranen
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Amir Sadeghi
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Marika Ruponen
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Veli-Pekka Ranta
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Kati-Sisko Vellonen
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Arto Urtti
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland; University of Helsinki, Faculty of Pharmacy, Drug Research Program, Yliopistonkatu 3, 00014 Helsinki, Finland
| | - Eva M Del Amo
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland.
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Kang N, Jung JS, Hwang J, Park SE, Kwon M, Yoon H, Yong J, Woo HM, Park KM. Beneficial Effect of Sirolimus-Pretreated Mesenchymal Stem Cell Implantation on Diabetic Retinopathy in Rats. Biomedicines 2024; 12:383. [PMID: 38397985 PMCID: PMC10886997 DOI: 10.3390/biomedicines12020383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/02/2024] [Accepted: 02/04/2024] [Indexed: 02/25/2024] Open
Abstract
BACKGROUND Diabetic retinopathy (DR) is a vision-threatening complication that affects virtually all diabetic patients. Various treatments have been attempted, but they have many side effects and limitations. Alternatively, stem cell therapy is being actively researched, but it faces challenges due to a low cell survival rate. In this study, stem cells were pretreated with sirolimus, which is known to promote cell differentiation and enhance the survival rate. Additionally, the subconjunctival route was employed to reduce complications following intravitreal injections. METHODS Diabetes mellitus was induced by intraperitoneal injection of 55 mg/kg of streptozotocin (STZ), and DR was confirmed at 10 weeks after DM induction through electroretinogram (ERG). The rats were divided into four groups: intact control group (INT), diabetic retinopathy group (DR), DR group with subconjunctival MSC injection (DR-MSC), and DR group with subconjunctival sirolimus-pretreated MSC injection (DR-MSC-S). The effects of transplantation were evaluated using ERG and histological examinations. RESULTS The ERG results showed that the DR-MSC-S group did not significantly differ from the INT in b-wave amplitude and exhibited significantly higher values than the DR-MSC and DR groups (p < 0.01). The flicker amplitude results showed that the DR-MSC and DR-MSC-S groups had significantly higher values than the DR group (p < 0.01). Histological examination revealed that the retinal layers were thinner in the DR-induced groups compared to the INT group, with the DR-MSC-S group showing the thickest retinal layers among them. CONCLUSIONS Subconjunctival injection of sirolimus-pretreated MSCs can enhance retinal function and mitigate histological changes in the STZ-induced DR rat model.
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Affiliation(s)
- Nanyoung Kang
- Laboratory of Veterinary Ophthalmology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea; (N.K.); (J.S.J.); (J.H.); (S.-E.P.); (M.K.); (H.Y.); (J.Y.)
| | - Ji Seung Jung
- Laboratory of Veterinary Ophthalmology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea; (N.K.); (J.S.J.); (J.H.); (S.-E.P.); (M.K.); (H.Y.); (J.Y.)
| | - Jiyi Hwang
- Laboratory of Veterinary Ophthalmology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea; (N.K.); (J.S.J.); (J.H.); (S.-E.P.); (M.K.); (H.Y.); (J.Y.)
| | - Sang-Eun Park
- Laboratory of Veterinary Ophthalmology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea; (N.K.); (J.S.J.); (J.H.); (S.-E.P.); (M.K.); (H.Y.); (J.Y.)
| | - Myeongjee Kwon
- Laboratory of Veterinary Ophthalmology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea; (N.K.); (J.S.J.); (J.H.); (S.-E.P.); (M.K.); (H.Y.); (J.Y.)
| | - Haerin Yoon
- Laboratory of Veterinary Ophthalmology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea; (N.K.); (J.S.J.); (J.H.); (S.-E.P.); (M.K.); (H.Y.); (J.Y.)
| | - Jungyeon Yong
- Laboratory of Veterinary Ophthalmology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea; (N.K.); (J.S.J.); (J.H.); (S.-E.P.); (M.K.); (H.Y.); (J.Y.)
| | - Heung-Myong Woo
- Laboratory of Veterinary Surgery, College of Veterinary Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea;
| | - Kyung-Mee Park
- Laboratory of Veterinary Ophthalmology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea; (N.K.); (J.S.J.); (J.H.); (S.-E.P.); (M.K.); (H.Y.); (J.Y.)
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Chacin Ruiz EA, Swindle-Reilly KE, Ford Versypt AN. Experimental and mathematical approaches for drug delivery for the treatment of wet age-related macular degeneration. J Control Release 2023; 363:464-483. [PMID: 37774953 PMCID: PMC10842193 DOI: 10.1016/j.jconrel.2023.09.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 10/01/2023]
Abstract
Several chronic eye diseases affect the posterior segment of the eye. Among them age-related macular degeneration can cause vision loss if left untreated and is one of the leading causes of visual impairment in the world. Most treatments are based on intravitreally injected therapeutics that inhibit the action of vascular endothelial growth factor. However, due to the need for monthly injections, this method is associated with poor patient compliance. To address this problem, numerous drug delivery systems (DDSs) have been developed. This review covers a selection of particulate systems, non-stimuli responsive hydrogels, implants, and composite systems that have been developed in the last few decades. Depending on the type of DDS, polymer material, and preparation method, different mechanical properties and drug release profiles can be achieved. Furthermore, DDS development can be optimized by implementing mathematical modeling of both drug release and pharmacokinetic aspects. Several existing mathematical models for diffusion-controlled, swelling-controlled, and erosion-controlled drug delivery from polymeric systems are summarized. Compartmental and physiologically based models for ocular drug transport and pharmacokinetics that have studied drug concentration profiles after intravitreal delivery or release from a DDS are also reviewed. The coupling of drug release models with ocular pharmacokinetic models can lead to obtaining much more efficient DDSs for the treatment of age-related macular degeneration and other diseases of the posterior segment of the eye.
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Affiliation(s)
- Eduardo A Chacin Ruiz
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Katelyn E Swindle-Reilly
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA; Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA; Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, USA
| | - Ashlee N Ford Versypt
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA; Department of Biomedical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA; Institute for Artificial Intelligence and Data Science, University at Buffalo, The State University of New York, Buffalo, NY, USA.
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Han H, Li S, Xu M, Zhong Y, Fan W, Xu J, Zhou T, Ji J, Ye J, Yao K. Polymer- and lipid-based nanocarriers for ocular drug delivery: Current status and future perspectives. Adv Drug Deliv Rev 2023; 196:114770. [PMID: 36894134 DOI: 10.1016/j.addr.2023.114770] [Citation(s) in RCA: 57] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/21/2023] [Accepted: 03/02/2023] [Indexed: 03/09/2023]
Abstract
Ocular diseases seriously affect patients' vision and life quality, with a global morbidity of over 43 million blindness. However, efficient drug delivery to treat ocular diseases, particularly intraocular disorders, remains a huge challenge due to multiple ocular barriers that significantly affect the ultimate therapeutic efficacy of drugs. Recent advances in nanocarrier technology offer a promising opportunity to overcome these barriers by providing enhanced penetration, increased retention, improved solubility, reduced toxicity, prolonged release, and targeted delivery of the loaded drug to the eyes. This review primarily provides an overview of the progress and contemporary applications of nanocarriers, mainly polymer- and lipid-based nanocarriers, in treating various eye diseases, highlighting their value in achieving efficient ocular drug delivery. Additionally, the review covers the ocular barriers and administration routes, as well as the prospective future developments and challenges in the field of nanocarriers for treating ocular diseases.
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Affiliation(s)
- Haijie Han
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China; Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China
| | - Su Li
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China
| | - Mingyu Xu
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China
| | - Yueyang Zhong
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China; Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China
| | - Wenjie Fan
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China
| | - Jingwei Xu
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China; Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China
| | - Tinglian Zhou
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China
| | - Jian Ji
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization of Ministry of Education, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Juan Ye
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China; Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China.
| | - Ke Yao
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China; Zhejiang Provincial Key Lab of Ophthalmology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, People's Republic of China.
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5
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Garkal A, Bangar P, Rajput A, Pingale P, Dhas N, Sami A, Mathur K, Joshi S, Dhuri S, Parikh D, Mutalik S, Mehta T. Long-acting formulation strategies for protein and peptide delivery in the treatment of PSED. J Control Release 2022; 350:538-568. [PMID: 36030993 DOI: 10.1016/j.jconrel.2022.08.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/18/2022] [Accepted: 08/21/2022] [Indexed: 12/17/2022]
Abstract
The invigoration of protein and peptides in serious eye disease includes age-related macular degeneration, choroidal neovascularization, retinal neovascularization, and diabetic retinopathy. The transportation of macromolecules like aptamers, recombinant proteins, and monoclonal antibodies to the posterior segment of the eye is challenging due to their high molecular weight, rapid degradation, and low solubility. Moreover, it requires frequent administration for prolonged therapy. The long-acting novel formulation strategies are helpful to overcome these issues and provide superior therapy. It avoids frequent administration, improves stability, high retention time, and avoids burst release. This review briefly enlightens posterior segments of eye diseases with their diagnosis techniques and treatments. This article mainly focuses on recent advanced approaches like intravitreal implants and injectables, electrospun injectables, 3D printed drug-loaded implants, nanostructure thin-film polymer devices encapsulated cell technology-based intravitreal implants, injectable and depots, microneedles, PDS with ranibizumab, polymer nanoparticles, inorganic nanoparticles, hydrogels and microparticles for delivering macromolecules in the eye for intended therapy. Furthermore, novel techniques like aptamer, small Interference RNA, and stem cell therapy were also discussed. It is predicted that these systems will make revolutionary changes in treating posterior segment eye diseases in future.
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Affiliation(s)
- Atul Garkal
- Department of Pharmaceutics, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat 382481, India
| | - Priyanka Bangar
- Department of Pharmaceutics, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat 382481, India
| | - Amarjitsing Rajput
- Department of Pharmaceutics, Bharti Vidyapeeth Deemed University, Poona College of Pharmacy, Pune, Maharashtra 411038, India
| | - Prashant Pingale
- Department of Pharmaceutics, GES's Sir Dr. M.S. Gosavi College of Pharmaceutical Education and Research, Nashik, Maharashtra 422005, India
| | - Namdev Dhas
- Department of Pharmaceutics, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka 576104, India
| | - Anam Sami
- Department of Pharmaceutics, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat 382481, India
| | - Khushboo Mathur
- Department of Pharmaceutics, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat 382481, India
| | - Shubham Joshi
- Department of Pharmaceutics, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat 382481, India
| | - Sonika Dhuri
- Department of Pharmaceutics, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat 382481, India
| | - Dhaivat Parikh
- Department of Pharmaceutics, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat 382481, India
| | - Srinivas Mutalik
- Department of Pharmaceutics, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka 576104, India
| | - Tejal Mehta
- Department of Pharmaceutics, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat 382481, India.
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Dosmar E, Vuotto G, Su X, Roberts E, Lannoy A, Bailey GJ, Mieler WF, Kang-Mieler JJ. Compartmental and COMSOL Multiphysics 3D Modeling of Drug Diffusion to the Vitreous Following the Administration of a Sustained-Release Drug Delivery System. Pharmaceutics 2021; 13:pharmaceutics13111862. [PMID: 34834276 PMCID: PMC8624029 DOI: 10.3390/pharmaceutics13111862] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 12/25/2022] Open
Abstract
The purpose of this study was to examine antibiotic drug transport from a hydrogel drug delivery system (DDS) using a computational model and a 3D model of the eye. Hydrogel DDSs loaded with vancomycin (VAN) were synthesized and release behavior was characterized in vitro. Four different compartmental and four COMSOL models of the eye were developed to describe transport into the vitreous originating from a DDS placed topically, in the subconjunctiva, subretinally, and intravitreally. The concentration of the simulated DDS was assumed to be the initial concentration of the hydrogel DDS. The simulation was executed over 1500 and 100 h for the compartmental and COMSOL models, respectively. Based on the MATLAB model, topical, subconjunctival, subretinal and vitreous administration took most (~500 h to least (0 h) amount of time to reach peak concentrations in the vitreous, respectively. All routes successfully achieved therapeutic levels of drug (0.007 mg/mL) in the vitreous. These models predict the relative build-up of drug in the vitreous following DDS administration in four different points of origin in the eye. Our model may eventually be used to explore the minimum loading dose of drug required in our DDS leading to reduced drug use and waste.
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Affiliation(s)
- Emily Dosmar
- Department of Biology and Biomedical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803, USA; (G.V.); (X.S.); (E.R.); (A.L.); (G.J.B.)
- Correspondence:
| | - Gabrielle Vuotto
- Department of Biology and Biomedical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803, USA; (G.V.); (X.S.); (E.R.); (A.L.); (G.J.B.)
| | - Xingqi Su
- Department of Biology and Biomedical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803, USA; (G.V.); (X.S.); (E.R.); (A.L.); (G.J.B.)
| | - Emily Roberts
- Department of Biology and Biomedical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803, USA; (G.V.); (X.S.); (E.R.); (A.L.); (G.J.B.)
| | - Abigail Lannoy
- Department of Biology and Biomedical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803, USA; (G.V.); (X.S.); (E.R.); (A.L.); (G.J.B.)
| | - Garet J. Bailey
- Department of Biology and Biomedical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803, USA; (G.V.); (X.S.); (E.R.); (A.L.); (G.J.B.)
| | - William F. Mieler
- Department of Biomedical Engineering, Illinois Institute of Technology, 10 W 35th St., Chicago, IL 60616, USA;
| | - Jennifer J. Kang-Mieler
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1200 W Harrison St., Chicago, IL 60607, USA;
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Fayyaz A, Vellonen KS, Ranta VP, Toropainen E, Reinisalo M, Valtari A, Puranen J, Ricci GD, Heikkinen EM, Gardner I, Ruponen M, Urtti A, Jamei M, Del Amo EM. Ocular pharmacokinetics of atenolol, timolol and betaxolol cocktail: Tissue exposures in the rabbit eye. Eur J Pharm Biopharm 2021; 166:155-162. [PMID: 34139290 DOI: 10.1016/j.ejpb.2021.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 06/04/2021] [Accepted: 06/10/2021] [Indexed: 11/28/2022]
Abstract
Quantitative understanding of pharmacokinetics of topically applied ocular drugs requires more research to further understanding and to eventually allow predictive in silico models to be developed. To this end, a topical cocktail of betaxolol, timolol and atenolol was instilled on albino rabbit eyes. Tear fluid, corneal epithelium, corneal stroma with endothelium, bulbar conjunctiva, anterior sclera, iris-ciliary body, lens and vitreous samples were collected and analysed using LC-MS/MS. Iris-ciliary body was also analysed after intracameral cocktail injection. Non-compartmental analysis was utilized to estimate the pharmacokinetics parameters. The most lipophilic drug, betaxolol, presented the highest exposure in all tissues except for tear fluid after topical administration, followed by timolol and atenolol. For all drugs, iris-ciliary body concentrations were higher than that of the aqueous humor. After topical instillation the most hydrophilic drug, atenolol, had 3.7 times higher AUCiris-ciliary body than AUCaqueous humor, whereas the difference was 1.4 and 1.6 times for timolol and betaxolol, respectively. This suggests that the non-corneal route (conjunctival-scleral) was dominating the absorption of atenolol, while the corneal route was more important for timolol and betaxolol. The presented data increase understanding of ocular pharmacokinetics of a cocktail of drugs and provide data that can be used for quantitative modeling and simulation.
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Affiliation(s)
- Anam Fayyaz
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland; Certara UK, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield S1 2BJ, United Kingdom
| | - Kati-Sisko Vellonen
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Veli-Pekka Ranta
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Elisa Toropainen
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Mika Reinisalo
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland; Institute of Clinical Medicine, Department of Ophthalmology, Faculty of Health Sciences, University of Eastern Finland, 70210 Kuopio, Finland
| | - Annika Valtari
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Jooseppi Puranen
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Giuseppe D'Amico Ricci
- University of Sassari, Department of Biomedical Sciences, Sassari, Italy; Asl Città di Torino, Ospedale Oftalmico di Torino, U.O.C Oculistica 2, Ospedale San Giovanni Bosco di Torino, Torino, Italy
| | - Emma M Heikkinen
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Iain Gardner
- Certara UK, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield S1 2BJ, United Kingdom
| | - Marika Ruponen
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland
| | - Arto Urtti
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland; University of Helsinki, Faculty of Pharmacy, Drug Research Program, Yliopistonkatu 3, 00014 Helsinki, Finland; Saint-Petersburg State University, Institute of Chemistry, Universitetskiy Prospekt, 26, Petergoff 198504, Russian Federation
| | - Masoud Jamei
- Certara UK, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield S1 2BJ, United Kingdom
| | - Eva M Del Amo
- University of Eastern Finland, School of Pharmacy, Biopharmaceutics, Yliopistonranta 1, 70210 Kuopio, Finland.
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8
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Naik S, Shreya AB, Raychaudhuri R, Pandey A, Lewis SA, Hazarika M, Bhandary SV, Rao BSS, Mutalik S. Small interfering RNAs (siRNAs) based gene silencing strategies for the treatment of glaucoma: Recent advancements and future perspectives. Life Sci 2020; 264:118712. [PMID: 33159955 DOI: 10.1016/j.lfs.2020.118712] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/28/2020] [Accepted: 10/31/2020] [Indexed: 01/22/2023]
Abstract
RNA-interference-based mechanisms, especially the use of small interfering RNAs (siRNAs), have been under investigation for the treatment of several ailments and have shown promising results for ocular diseases including glaucoma. The eye, being a confined compartment, serves as a good target for the delivery of siRNAs. This review focuses on siRNA-based strategies for gene silencing to treat glaucoma. We have discussed the ocular structures and barriers to gene therapy (tear film, corneal, conjunctival, vitreous, and blood ocular barriers), methods of administration for ocular gene delivery (topical instillation, periocular, intracameral, intravitreal, subretinal, and suprachoroidal routes) and various viral and non-viral vectors in siRNA-based therapy for glaucoma. The components and mechanism of siRNA-based gene silencing have been mentioned briefly followed by the basic strategies and challenges faced during siRNA therapeutics development. We have emphasized different therapeutic targets for glaucoma which have been under research by scientists and the current siRNA-based drugs used in glaucoma treatment. We also mention briefly strategies for siRNA-based treatment after glaucoma surgery.
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Affiliation(s)
- Santoshi Naik
- Department of Pharmaceutics, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka State, India
| | - Ajjappla Basavaraj Shreya
- Department of Pharmaceutics, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka State, India
| | - Ruchira Raychaudhuri
- Department of Pharmaceutics, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka State, India
| | - Abhijeet Pandey
- Department of Pharmaceutics, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka State, India
| | - Shaila A Lewis
- Department of Pharmaceutics, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka State, India
| | - Manali Hazarika
- Department of Ophthalmology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal 576104, Karnataka State, India
| | - Sulatha V Bhandary
- Department of Ophthalmology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal 576104, Karnataka State, India
| | - Bola Sadashiva Satish Rao
- Director - Research, Directorte of Research, Manipal Academy of Higher Education, Manipal and School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka State, India
| | - Srinivas Mutalik
- Department of Pharmaceutics, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka State, India.
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9
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Abstract
Retinal diseases, such as age-related macular degeneration and diabetic retinopathy, are the leading causes of blindness worldwide. The mainstay of treatment for these blinding diseases remains to be surgery, and the available pharmaceutical therapies on the market are limited, partially owing to various biological barriers in hindering the delivery of therapeutics to the retina. The nanoparticulate drug delivery system confers the capability for delivering therapeutics to the specific ocular targets and, hence, potentially revolutionizes the current treatment landscape of retinal diseases. While the research to date indicates the enormous therapeutics potentials of the nanoparticulate delivery systems, the successful translation of these systems from the bench to bedside is challenging and requires a combined understanding of retinal pathology, physiology of the eye, and particle and formulation designs of nanoparticles. To this end, the review begins with an overview of the most prevalent retinal diseases and related pharmacotherapy. Highlights of the current challenges encountered in ocular drug delivery for each administration route are provided, followed by critical appraisal of various nanoparticulate drug delivery systems for the retinal diseases, including their formulation designs, therapeutic merits, limitations, and future direction. It is believed that a greater understanding of the nano-biointeraction in eyes will lead to the development of more sophisticated drug delivery systems for retinal diseases.
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Affiliation(s)
- Qingqing Li
- Faculty of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jingwen Weng
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Si Nga Wong
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Wai Yip Thomas Lee
- Aptorum Group Limited, Unit 232, 12 Science Park West Avenue, Hong Kong Science Park, Shatin New Town, Hong Kong
| | - Shing Fung Chow
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong
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Radhakrishnan K, Vincent A, Joseph RR, Moreno M, Dickescheid A, Agrawal R, Venkatraman S. Hollow Microcapsules as Periocular Drug Depot for Sustained Release of Anti-VEGF Protein. Pharmaceutics 2019; 11:E330. [PMID: 31336771 PMCID: PMC6680760 DOI: 10.3390/pharmaceutics11070330] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/03/2019] [Accepted: 07/06/2019] [Indexed: 01/30/2023] Open
Abstract
Diseases affecting the posterior segment of the eye such as age-related macular degeneration and diabetic retinopathy are leading causes of blindness all over the world. The current treatment regimen for such diseases involves repeated intravitreal injections of anti- Vascular Endothelial Growth Factor (VEGF) proteins. This method is highly invasive and can lead to severe complications. In an attempt to develop less invasive alternatives, we propose the use of a controlled release system consisting of anti-VEGF loaded hollow microcapsules that can be administered periocularly to form drug eluting depots on the episcleral surface. The microcapsules with either positive or negative surface charge were prepared by a layer by layer approach and showed pH responsive permeability switching. An ex vivo experiment using porcine sclera indicated positively charged microcapsules remained on the episcleral surface over four days while the negatively charged microcapsules were washed away. These positively charged microcapsules were then loaded with anti-VEGF protein ranibizumab using pH dependent permeability switching and protein release from the microcapsules were studied using an in vitro setup. An ex vivo experiment utilizing porcine sclera demonstrated sustained release of ranibizumab over seven days with zero-order kinetics.
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Affiliation(s)
- Krishna Radhakrishnan
- NTU-Northwestern Institute for Nanomedicine (NNIN), School of Materials Science and Engineering, Nanyang Technological University (NTU), 50, Nanyang Avenue, Singapore 639798, Singapore.
| | - Anita Vincent
- NTU-Northwestern Institute for Nanomedicine (NNIN), School of Materials Science and Engineering, Nanyang Technological University (NTU), 50, Nanyang Avenue, Singapore 639798, Singapore
| | - Rini Rachel Joseph
- NTU-Northwestern Institute for Nanomedicine (NNIN), School of Materials Science and Engineering, Nanyang Technological University (NTU), 50, Nanyang Avenue, Singapore 639798, Singapore
| | - Miguel Moreno
- NTU-Northwestern Institute for Nanomedicine (NNIN), School of Materials Science and Engineering, Nanyang Technological University (NTU), 50, Nanyang Avenue, Singapore 639798, Singapore
| | - Andreas Dickescheid
- NTU-Northwestern Institute for Nanomedicine (NNIN), School of Materials Science and Engineering, Nanyang Technological University (NTU), 50, Nanyang Avenue, Singapore 639798, Singapore
| | - Rupesh Agrawal
- Tan Tock Seng Hospital, Novena, Singapore 308433, Singapore
| | - Subbu Venkatraman
- NTU-Northwestern Institute for Nanomedicine (NNIN), School of Materials Science and Engineering, Nanyang Technological University (NTU), 50, Nanyang Avenue, Singapore 639798, Singapore.
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11
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Hydrogels for sustained delivery of biologics to the back of the eye. Drug Discov Today 2019; 24:1470-1482. [PMID: 31202673 DOI: 10.1016/j.drudis.2019.05.037] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 04/11/2019] [Accepted: 05/31/2019] [Indexed: 12/31/2022]
Abstract
Hydrogels are water-laden polymer networks that have been used for myriad biological applications. By controlling the chemistry through which a hydrogel is constructed, a wide range of chemical and physical properties can be accessed, making them an attractive class of biomaterials. In this review, we cover the application of hydrogels for sustained delivery of biologics to the back of the eye. In adapting hydrogels to this purpose, success is dependent on careful consideration of material properties, route of administration, means of injection, and control of drug efflux, all of which are addressed. We also provide a perspective on clinical and chemistry, manufacturing and controls (CMC) considerations that are integral to the development of an ocular hydrogel delivery system.
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12
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The route of administration influences the therapeutic index of an anti-proNGF neutralizing mAb for experimental treatment of Diabetic Retinopathy. PLoS One 2018; 13:e0199079. [PMID: 29927948 PMCID: PMC6013198 DOI: 10.1371/journal.pone.0199079] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/31/2018] [Indexed: 12/22/2022] Open
Abstract
Many neurodegenerative retinal diseases are treated with monoclonal antibodies (mAb) delivered by invasive intravitreal injection (IVT). In Diabetic Retinopathy there is a scarcity of effective agents that can be delivered using non-invasive methods, and there are significant challenges in the validation of novel therapeutic targets. ProNGF represents a potential novel target, and IVT administration of a function-blocking anti-proNGF mAb is therapeutic in a mouse model of DR. We therefore compared invasive IVT to less invasive systemic intravenous (IV) and local subconjunctival (SCJ) administration, for therapy of Diabetic Retinopathy. The IV and SCJ routes are safe, afford sustained pharmacokinetics and tissue penetration of anti-proNGF mAb, and result in long–term therapeutic efficacy that blocks retinal inflammation, edema, and neuronal death. SCJ may be a more convenient and less-invasive approach for ophthalmic use and may enable reduced frequency of intervention for the treatment of retinal pathologies.
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13
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Li Q, Lai KL, Chan PS, Leung SC, Li HY, Fang Y, To KKW, Choi CHJ, Gao QY, Lee TWY. Micellar delivery of dasatinib for the inhibition of pathologic cellular processes of the retinal pigment epithelium. Colloids Surf B Biointerfaces 2016; 140:278-286. [PMID: 26764115 DOI: 10.1016/j.colsurfb.2015.12.053] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 12/10/2015] [Accepted: 12/23/2015] [Indexed: 12/12/2022]
Abstract
The objective of this study was to fabricate dasatinib-loaded nanoparticles and evaluate their efficacy in inhibiting cellular processes of the retinal pigment epithelium (RPE) related to proliferative vitreoretinopathy (PVR), for which there are no approved pharmacological approaches. We successfully encapsulated dasatinib, a poorly soluble multi-targeted tyrosine kinase inhibitor which has great potential for the treatment of PVR, into nanoparticles prepared from micellation of PEG-b-PCL. The size of the nanomicelles was approximately 55nm with a narrow distribution. They increased the solubility of dasatinib by 475× and provided a sustained drug release. ARPE-19, an immortal RPE cell line, was used to assess the in vitro efficacy of micellar dasatinib because the RPE is believed to play a key role in the pathogenesis of PVR. Three cell-based assays, namely, proliferation, adhesion and migration, which represent three important PVR-related cellular changes of the RPE, were conducted and the cytotoxicity of micelles was also evaluated. Both blank and dasatinib-loaded micelles were non-cytotoxic towards ARPE-19 cells. Micellar dasatinib significantly inhibited cell proliferation, adhesion and migration compared to the free drug; this might be attributable to enhanced solubility. PEG-b-PCL micelles were taken up into the ARPE-19 cells by an energy-dependent clatharin and caveolae-mediated endocytosis. Our results indicated that cellular uptake and the anti-proliferation effect of drugloaded micelles were linearly correlated. Drug loading appears to be a critical parameter for cellular uptake which in turn impacts the in vitro bioactivities of polymeric micelles. Our results clearly demonstrated that dasatinib-encapsulated micelles offer considerable promise in the management of PVR.
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Affiliation(s)
- Qingqing Li
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Ka Lun Lai
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Pui Shan Chan
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Sui Chu Leung
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Ho Yin Li
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Yuan Fang
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Kenneth K W To
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Chung Hang J Choi
- Division of Biomedical Engineering, Department of Electronic Engineering, Faculty of Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Qian Ying Gao
- State Key Laboratory of Ophthalmology, ZhongShan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Thomas W Y Lee
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
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14
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Shen HH, Chan EC, Lee JH, Bee YS, Lin TW, Dusting GJ, Liu GS. Nanocarriers for treatment of ocular neovascularization in the back of the eye: new vehicles for ophthalmic drug delivery. Nanomedicine (Lond) 2015; 10:2093-107. [PMID: 26096379 DOI: 10.2217/nnm.15.47] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Pathologic neovascularization of the retina is a major cause of substantial and irreversible loss of vision. Drugs are difficult to deliver to the lesions in the back of the eye and this is a major obstacle for the therapeutics. Current pharmacological approach involves an intravitreal injection of anti-VEGF agents to prevent aberrant growth of blood vessels, but it has limitations including therapeutic efficacy and side-effects associated with systemic exposure and invasive surgery. Nanotechnology provides novel opportunities to overcome the limitations of conventional delivery system to reach the back of the eye through fabrication of nanostructures capable of encapsulating and delivering small molecules. This review article introduces various forms of nanocarrier that can be adopted by ocular drug delivery systems to improve current therapy. The application of nanotechnology in medicine brings new hope for ocular drug delivery in the back of the eye to manage the major causes of blindness associated with ocular neovascularization.
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Affiliation(s)
- Hsin-Hui Shen
- Department of Microbiology, Monash University, Clayton, Melbourne, VIC, Australia
| | - Elsa C Chan
- Centre for Eye Research Australia, East Melbourne, VIC, Australia.,Department of Ophthalmology, University of Melbourne, East Melbourne, VIC, Australia
| | - Jia Hui Lee
- Centre for Eye Research Australia, East Melbourne, VIC, Australia
| | - Youn-Shen Bee
- Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.,Yuh-Ing Junior College of Health Care & Management, Kaohsiung, Taiwan.,National Defense Medical Center, Taipei, Taiwan
| | - Tsung-Wu Lin
- Department of Chemistry, Tunghai University, Taichung City, Taiwan
| | - Gregory J Dusting
- Centre for Eye Research Australia, East Melbourne, VIC, Australia.,Department of Ophthalmology, University of Melbourne, East Melbourne, VIC, Australia
| | - Guei-Sheung Liu
- Centre for Eye Research Australia, East Melbourne, VIC, Australia.,Department of Ophthalmology, University of Melbourne, East Melbourne, VIC, Australia
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15
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Hartnett TE, O’Connor AJ, Ladewig K. Cubosomes and other potential ocular drug delivery vehicles for macromolecular therapeutics. Expert Opin Drug Deliv 2015; 12:1513-26. [DOI: 10.1517/17425247.2015.1021680] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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16
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Kim YC, Chiang B, Wu X, Prausnitz MR. Ocular delivery of macromolecules. J Control Release 2014; 190:172-81. [PMID: 24998941 PMCID: PMC4142116 DOI: 10.1016/j.jconrel.2014.06.043] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Accepted: 06/23/2014] [Indexed: 12/22/2022]
Abstract
Biopharmaceuticals are making increasing impact on medicine, including treatment of indications in the eye. Macromolecular drugs are typically given by physician-administered invasive delivery methods, because non-invasive ocular delivery methods, such as eye drops, and systemic delivery, have low bioavailability and/or poor ocular targeting. There is a need to improve delivery of biopharmaceuticals to enable less-invasive delivery routes, less-frequent dosing through controlled-release drug delivery and improved drug targeting within the eye to increase efficacy and reduce side effects. This review discusses the barriers to drug delivery via various ophthalmic routes of administration in the context of macromolecule delivery and discusses efforts to develop controlled-release systems for delivery of biopharmaceuticals to the eye. The growing number of macromolecular therapies in the eye needs improved drug delivery methods that increase drug efficacy, safety and patient compliance.
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Affiliation(s)
- Yoo Chun Kim
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Bryce Chiang
- Wallace Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Xianggen Wu
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao 266071, China
| | - Mark R Prausnitz
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; Wallace Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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17
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Nanotherapy for posterior eye diseases. J Control Release 2014; 193:100-12. [PMID: 24862316 DOI: 10.1016/j.jconrel.2014.05.031] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 05/12/2014] [Accepted: 05/17/2014] [Indexed: 12/11/2022]
Abstract
It is assumed that more than 50% of the most enfeebling ocular diseases have their origin in the posterior segment. Furthermore, most of these diseases lead to partial or complete blindness, if left untreated. After cancer, blindness is the second most dreaded disease world over. However, treatment of posterior eye diseases is more challenging than the anterior segment ailments due to a series of anatomical barriers and physiological constraints confronted for delivery to this segment. In this regard, nanostructured drug delivery systems are proposed to defy ocular barriers, target retina, and act as permeation enhancers in addition to providing a controlled release. Since an important step towards developing effective treatment strategies is to understand the course or a route a drug molecule needs to follow to reach the target site, the first part of the present review discusses various pathways available for effective delivery to and clearance from the posterior eye. Promise held by nanocarrier systems, viz. liposomes, nanoparticles, and nanoemulsion, for effective delivery and selective targeting is also discussed with illustrative examples, tables, and flowcharts. However, the applicability of these nanocarrier systems as self-administration ocular drops is still an unrealized dream which is in itself a huge technological challenge.
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Prieto E, Pérez S, Pablo LE, García MA, Bregante MA. Vitreous pharmacokinetics and bioavailability of memantine after subtenon, intravenous, and intravitreal administration in rabbits. J Ocul Pharmacol Ther 2014; 30:392-9. [PMID: 24597794 DOI: 10.1089/jop.2013.0193] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE This study evaluated the vitreous pharmacokinetics and vitreous bioavailability of memantine following posterior-subtenon administration (PST) compared to intravitreal (INT) and intravenous routes (INV) in rabbits. METHODS Vitreous pharmacokinetic analysis was performed on female New Zealand (NZ) albino rabbits after PST, INT, and INV administration and calculating the pharmacokinetic parameters that describe memantine vitreous distribution. The vitreous bioavailability (F) and the relative vitreous bioavailability of memantine was estimated after posterior-subtenon administration (Frel (pst/int)) and after intravenous route (Frel (inv/int)) compared with intravitreal administration. Relative vitreous bioavailability of memantine was also estimated following PST administration compared with vitreous concentrations after intravenous administration (Frel (pst/inv)). RESULTS Memantine kinetics in the vitreous of NZ albino rabbits after PST administration can be explained by a one-compartment model, which was characterized by a fast absorption process, and a short terminal half-life. Vitreous pharmacokinetics following INV administration was also characterized by a fast absorption process, a terminal half-life significantly longer than the subtenon route, and low area under the curve values. High vitreous bioavailability after PST was observed, and the relative vitreous bioavailability of memantine following PST administration (0.53%) was greater than for intravenous administration (0.02%). CONCLUSIONS Our results suggest that memantine reaches the vitreous after PST administration by local diffusion. These data also show that local diffusion of the drug is responsible for greater vitreous availability of memantine following PST administration compared with INV administration.
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Affiliation(s)
- Esther Prieto
- 1 Department of Ophthalmology, Miguel Servet University Hospital and Aragon Health Sciences Institute (I+CS), University of Zaragoza , Zaragoza, Spain
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Shah SS, Denham LV, Elison JR, Bhattacharjee PS, Clement C, Huq T, Hill JM. Drug delivery to the posterior segment of the eye for pharmacologic therapy. EXPERT REVIEW OF OPHTHALMOLOGY 2014; 5:75-93. [PMID: 20305803 DOI: 10.1586/eop.09.70] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Treatment of diseases of the posterior segment of the eye, such as age-related macular degeneration, cytomegalovirus retinitis, diabetic retinopathy, posterior uveitis and retinitis pigmentosa, requires novel drug delivery systems that can overcome the many barriers for efficacious delivery of therapeutic drug concentrations. This challenge has prompted the development of biodegradable and nonbiodegradable sustained-release systems for injection or transplantation into the vitreous as well as drug-loaded nanoparticles, microspheres and liposomes. These drug delivery systems utilize topical, systemic, subconjunctival, intravitreal, transscleral and iontophoretic routes of administration. The focus of research has been the development of methods that will increase the efficacy of spatiotemporal drug application, resulting in more successful therapy for patients with posterior segment diseases. This article summarizes recent advances in the research and development of drug delivery methods of the posterior chamber of the eye, with an emphasis on the use of implantable devices as well as micro- and nanoparticles.
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Affiliation(s)
- Shalin S Shah
- Department of Ophthalmology, Louisiana State University Health Sciences Center (LSUHSC), 2020 Gravier St. Suite B, Room 3E6, New Orleans, LA 70112-2234, USA, Tel.: +1 678 296 2334, ,
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20
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Abstract
The eye is a highly protected organ, and designing an effective therapy is often considered a challenging task. The anatomical and physiological barriers result in low ocular bioavailability of drugs. Due to these constraints, less than 5% of the administered dose is absorbed from the conventional ophthalmic dosage forms. Further, physicochemical properties such as lipophilicity, molecular weight and charge modulate the permeability of drug molecules. Vision-threatening diseases such as glaucoma, diabetic macular edema, cataract, wet and dry age-related macular degeneration, proliferative vitreoretinopathy, uveitis, and cytomegalovirus retinitis alter the pathophysiological and molecular mechanisms. Understanding these mechanisms may result in the development of novel treatment modalities. Recently, transporter/receptor targeted prodrug approach has generated significant interest in ocular drug delivery. These transporters and receptors are involved in the transport of essential nutrients, vitamins, and xenobiotics across biological membranes. Several influx transporters (peptides, amino acids, glucose, lactate and nucleosides/nucleobases) and receptors (folate and biotin) have been identified on conjunctiva, cornea, and retina. Structural and functional delineation of these transporters will enable more drugs targeting the posterior segment to be successfully delivered topically. Prodrug derivatization targeting transporters and receptors expressed on ocular tissues has been the subject of intense research. Several prodrugs have been designed to target these transporters and enhance the absorption of poorly permeating parent drug. Moreover, this approach might be used in gene delivery to modify cellular function and membrane receptors. This review provides comprehensive information on ocular drug delivery, with special emphasis on the use of transporters and receptors to improve drug bioavailability.
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22
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Li SK, Hao J, Liu H, Lee JH. MRI study of subconjunctival and intravitreal injections. J Pharm Sci 2012; 101:2353-63. [PMID: 22473517 DOI: 10.1002/jps.23127] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 02/21/2012] [Accepted: 03/01/2012] [Indexed: 11/06/2022]
Abstract
Previous magnetic resonance imaging (MRI) studies to investigate the routes of penetration and barriers in ocular delivery have provided insights into the mechanisms of transscleral and intraocular drug delivery. The objective of the present study was to investigate ocular penetration and clearance after subconjunctival and intravitreal injections using a contrast agent at concentrations higher than those in the previous studies. This high concentration approach was hypothesized to allow the visualization of the contrast agent in the eye that could not be achieved previously. Subconjunctival and intravitreal injections of contrast agent Magnevist, a model hydrophililc probe, were performed in rabbits, and the distribution and clearance of the probe after the injections were examined by MRI. After subconjunctival injection in vivo, significant contrast agent penetration into the anterior chamber was observed but not into the vitreous. A clearance pathway of the hydrophilic probe from the subconjunctival depot to the regions near the periocular fat behind the eye was found. After intravitreal injection in vivo, the contrast agent was observed in the anterior chamber, optic nerve, and tissues surrounding the eye during clearance. MRI continues to provide insights into the transport barriers and clearance pathways of hydrophilic molecules in ocular delivery.
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Affiliation(s)
- S Kevin Li
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, Cincinnati, Ohio 45267, USA.
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23
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Thakur A, Scheinman RI, Rao VR, Kompella UB. Pazopanib, a multitargeted tyrosine kinase inhibitor, reduces diabetic retinal vascular leukostasis and leakage. Microvasc Res 2011; 82:346-50. [PMID: 21945644 DOI: 10.1016/j.mvr.2011.09.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 08/17/2011] [Accepted: 09/08/2011] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To determine the efficacy of pazopanib eye drops in the streptozotocin induced diabetic retinopathy rat model. METHODS A 0.5% w/v pazopanib suspension was prepared in phosphate buffered saline (PBS, pH 7.4) in the presence of 0.5% w/v sodium carboxymethyl cellulose. Brown Norway rats were divided into three groups (n=4) - (1) healthy, (2) diabetic, and (3) diabetic with treatment. The drug suspension was administered twice daily as eye drops to group 3 for 30 days. Efficacy parameters including the number of adherent leukocytes in the retinal vasculature (leukostasis), blood-retinal FITC-dextran leakage, and vitreous-to-plasma protein ratio were measured. RESULTS Pazopanib suspension in the form of eye drops significantly reduced leukostasis (32%), FITC-dextran leakage (39%), and the vitreous-to-plasma protein ratio (64%) in diabetic animals compared to untreated diabetic group. CONCLUSION Pazopanib eye drops can alleviate retinal complications of diabetic retinopathy.
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Affiliation(s)
- Ashish Thakur
- Nanomedicine and Drug Delivery Laboratory, Department of Pharmaceutical Sciences, Aurora, CO 80045, USA
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Baid R, Tyagi P, Durazo SA, Kompella UB. Protein Drug Delivery and Formulation Development. DRUG PRODUCT DEVELOPMENT FOR THE BACK OF THE EYE 2011. [DOI: 10.1007/978-1-4419-9920-7_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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25
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Buitrago E, Höcht C, Chantada G, Fandiño A, Navo E, Abramson DH, Schaiquevich P, Bramuglia GF. Pharmacokinetic analysis of topotecan after intra-vitreal injection. Implications for retinoblastoma treatment. Exp Eye Res 2010; 91:9-14. [DOI: 10.1016/j.exer.2010.03.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2010] [Revised: 03/08/2010] [Accepted: 03/12/2010] [Indexed: 12/17/2022]
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26
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Ocular pharmacokinetic study of a corticosteroid by 19F MR. Exp Eye Res 2010; 91:347-52. [PMID: 20537996 DOI: 10.1016/j.exer.2010.05.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 04/22/2010] [Accepted: 05/26/2010] [Indexed: 11/21/2022]
Abstract
Traditional ocular pharmacokinetic studies are invasive and cannot be easily applied to humans in vivo. To acquire in vivo ocular pharmacokinetic data noninvasively, (19)F MR on a 3T clinical scanner was used to follow the real time dynamics of a corticosteroid in the eye. (1)H MR was also performed to locate the site of administration. Triamcinolone acetonide phosphate (TAP) was the model drug, administered by intravitreal and subconjunctival injections. TAP pharmacokinetics were monitored by changes in the (19)F spectrum of the intraocular drug in real time. The elimination half-lives of TAP in the eye after intravitreal and subconjunctival injections were 8 and 0.5 h in vivo and 17 and 6.0 h postmortem, respectively. The half-lives associated with clearance were 14 h for intravitreal injection and 0.5 h for subconjunctival injection.
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New techniques for drug delivery to the posterior eye segment. Pharm Res 2010; 27:530-43. [PMID: 20155388 DOI: 10.1007/s11095-009-0042-9] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 12/15/2009] [Indexed: 10/19/2022]
Abstract
Ocular drug delivery has become an increasingly important field of research especially when treating posterior segment diseases of the eye, such as age-related macular degeneration, diabetic retinopathy, posterior uveitis and retinitis. These diseases are the leading causes of vision loss in developed countries which require repeated long-term administration of therapeutic agents. New drugs for the medication of the posterior ocular segment have emerged, but most drugs are delivered by repeated intravitreal injections associated with ocular complications. Advances in ocular drug delivery system research are expected to provide new tools for the treatment of the posterior segment diseases, providing improved drug penetration, prolonged action, higher efficacy, improved safety and less invasive administration, resulting in higher patient compliance. This review provides an insight into the recent progress and trends in ocular drug delivery systems for treating posterior eye segment diseases, with an emphasis on transscleral iontophoresis.
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Wai-Yip Lee T, Robinson JR. Drug Delivery to the Posterior Segment of the Eye IV: Theoretical Formulation of a Drug Delivery System for Subconjunctival Injection. J Ocul Pharmacol Ther 2009; 25:29-37. [DOI: 10.1089/jop.2008.0010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Thomas Wai-Yip Lee
- Pharmaceutical and Analytical Development, Novartis Pharmaceuticals Corporation, East Hanover, New Jersey
- Current Address: Formulations Research and Development, Celgene Corporation, Summit, New Jersey
| | - Joseph R. Robinson
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin–Madison, Madison, Wisconsin
- Department of Ophthalmology, School of Medicine, University of Wisconsin–Madison, Madison, Wisconsin
- Deceased
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Miller DJ, Li SK, Tuitupou AL, Kochambilli RP, Papangkorn K, Mix DC, Higuchi WI, Higuchi JW. Passive and oxymetazoline-enhanced delivery with a lens device: pharmacokinetics and efficacy studies with rabbits. J Ocul Pharmacol Ther 2009; 24:385-91. [PMID: 18665810 DOI: 10.1089/jop.2007.0116] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE The aims of this study were to assess the trans-scleral delivery of dexamethasone phosphate (DexP) with a prototype lens device and a formulation comprising a vasoconstrictor and to determine the efficacy of this delivery system in treating experimentally induced uveitis in a rabbit model. METHODS Passive trans-scleral delivery was performed on New Zealand white rabbits in vivo, using the lens device and a formulation of 0.034 M oxymetazoline (OMZ, the vasoconstrictor) and 0.5 M of dexamethasone sodium phosphate (DexNaP). Trans-scleral delivery of DexP without OMZ was the control. The amounts of DexP delivered into the eye and its distributions in the eye were determined by dissection of the eye and high-performance liquid chromatography assay in the pharmacokinetics study. The efficacy of the DexP delivery system in treating lipopolysaccharide-induced uveitis was also evaluated in the rabbit model in vivo. The effect of OMZ upon DexP delivery and its treatment efficacy was studied by comparing the DexP results with and without OMZ. RESULTS In the pharmacokinetics study, the amounts of DexP delivered into the eye using the lens system with OMZ were significantly higher than those without OMZ. The results in the efficacy study showed a better treatment outcome with OMZ to relieve the symptoms of endotoxin-induced uveitis in rabbits. CONCLUSIONS The potential of vasoconstrictors to enhance eye disease treatments in passive trans-scleral drug delivery was demonstrated. The higher DexP level in the eye and the improvement of the outcome in the efficacy study in the presence of the vasoconstrictor are consistent with the hypothesis that the vasoconstrictor enhances drug delivery by decreasing clearance.
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Lee SJ, Kim SJ, Kim ES, Geroski DH, McCarey BE, Edelhauser HF. Trans-scleral permeability of Oregon green 488. J Ocul Pharmacol Ther 2008; 24:579-86. [PMID: 19049298 DOI: 10.1089/jop.2008.0050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE The aim of this study was to determine the scleral permeability of a commercially available version of 2',7'-difluorofluorescein (OG) and compare it to that of sodium fluorescein (NaF). METHODS Both in vitro and in vivo experiments were performed. For the ex vivo experiment, a Lucite block perfusion chamber with human donor sclera was used. Two hundred microliters (200 microL) of 2.5 mg/ml OG or NaF was placed in the donor chamber. The OG and NaF concentration that diffused across the sclera was measured every 2 h for 24 h by fluorometry, and the fluorescence in the sclera was examined by fluorescent microscopy. In vivo experiments consisted of live rabbits treated with a 0.2-mL subtenon injection of 7.5 mg/ml solution of either OG or NaF in the right eye. Intraocular fluorescence was measured by ocular fluorophotometry. RESULTS The scleral permeability coefficient (K(trans)) of OG was 3.93 +/- 1.01 x 10(-7) cm/sec and that of NaF was 4.41 +/- 1.32 x 10(-7) cm/s. Both OG and NaF were visible throughout the sclera after 24 hours. Peak vitreous concentration after subtenon injection in rabbits was 6.48 +/- 2.65 ng/mL of OG at 2 min and 47.15 +/- 13.3 ng/mL of NaF at 10 min. CONCLUSIONS OG was able to diffuse across the sclera and thus could be potentially useful as a fluorescent tag for intraocular drug delivery studies. However, its permeability was substantially less than that of NaF.
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Affiliation(s)
- Sung Jin Lee
- Department of Ophthalmology, College of Medicine, Soonchunhyang University, Seoul, Korea
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Proksch JW, Ward KW. Cassette dosing pharmacokinetic studies for evaluation of ophthalmic drugs for posterior ocular diseases. J Pharm Sci 2008; 97:3411-21. [PMID: 17948915 DOI: 10.1002/jps.21188] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose of this investigation was to evaluate the utility of cassette dosing as a means for increasing throughput and decreasing animal usage for intravitreal ocular pharmacokinetic studies. Pigmented rabbits received a single intravitreal injection of test article containing either a single compound or a mixture of up to five compounds. Samples of vitreous, choroid and retina were collected at predetermined intervals through 7 or 28 days after dosing. Concentrations of each compound were determined by LC/MS/MS, with subsequent pharmacokinetic data analysis. The ocular pharmacokinetic properties of four test compounds administered as a cassette were in agreement with the ocular pharmacokinetics of each compound when administered as a single entity. Cassette dosing was subsequently used to screen an additional 15 compounds, with injection of 5 compounds per study. Based on the results from these cassette-dosing studies, some compounds demonstrated favorable ocular pharmacokinetics, with sustained concentrations above 300 ng/g in retina for at least 1 week after dosing while other compounds showed either considerably less penetration into retina or a shorter residence time in the retina. These findings suggest that the cassette dosing approach can be used in evaluating the intravitreal ocular pharmacokinetic properties of compounds intended for ocular use.
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Affiliation(s)
- Joel W Proksch
- Global Preclinical Development, Bausch & Lomb, 1400 N. Goodman Street, Rochester, New York 14609, USA.
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Jiang J, Moore JS, Edelhauser HF, Prausnitz MR. Intrascleral drug delivery to the eye using hollow microneedles. Pharm Res 2008; 26:395-403. [PMID: 18979189 DOI: 10.1007/s11095-008-9756-3] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 10/10/2008] [Indexed: 12/16/2022]
Abstract
PURPOSE This study tested the hypothesis that hollow microneedles can infuse solutions containing soluble molecules, nanoparticles, and microparticles into sclera in a minimally invasive manner. METHODS Individual hollow microneedles were inserted into, but not across, human cadaver sclera and aqueous solutions containing sulforhodamine or fluorescently tagged nanoparticles or microparticles were infused into sclera at constant pressure. The infused volume of fluid was measured and imaged histologically as a function of scleral thickness, infusion pressure, needle retraction depth and the presence of spreading enzymes (hyaluronidase and collagenase). RESULTS Individual hollow microneedles were able to insert into sclera. Fluid infusion was extremely slow after microneedle insertion into the sclera without retraction, but partial retraction of the microneedle over a distance of 200-300 microm enabled infusion of 10-35 microl of fluid into the tissue. Scleral thickness and infusion pressure had insignificant effects on fluid delivery. Nanoparticle suspensions were also delivered into sclera, but microparticles were delivered only in the presence of hyaluronidase and collagenase spreading enzymes, which suggested the role of scleral glycosaminoglycans and collagen fibers as rate-limiting barriers. CONCLUSION This study shows that hollow microneedles can infuse solutions into the sclera for minimally invasive delivery of soluble molecules, nanoparticles and microparticles.
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Affiliation(s)
- Jason Jiang
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0100, USA
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Computer modeling of drug delivery to the posterior eye: effect of active transport and loss to choroidal blood flow. Pharm Res 2008; 25:2685-96. [PMID: 18679772 DOI: 10.1007/s11095-008-9691-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 07/17/2008] [Indexed: 10/21/2022]
Abstract
PURPOSE The direct penetration route following transscleral drug administration presents several barrier and clearance mechanisms-including loss to choroidal blood flow, active transport by the retinal pigment epithelium (RPE), and loss to the conjunctival lymphatics and episcleral blood vessels. The objective of this research was to quantify the role of choroidal and episcleral losses. MATERIALS AND METHODS A finite element model was created for drug distribution in the posterior human eye. The volumetric choroidal loss constant, active transport component and mass transfer from the scleral surface were unknown parameters in the model. The model was used to simulate drug distribution from a systemic source, and the results were compared to existing experimental results to obtain values for the parameters. RESULTS The volumetric choroidal loss constant, mass transfer coefficient from the scleral surface and active transport component were evaluated to be (2.0 +/- 0.6) x 10(-5) s(-1), (2.0 +/- 0.35) x 10(-5) cm/s and 8.54 x 10(-6) cm/s respectively. CONCLUSION Loss to the choroidal circulation was small compared to loss from the scleral surface. Active transport was predicted to induce periscleral movement of the drug, resulting in more rapid distribution and elevated drug concentrations in the choroid and sclera.
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Lindsey JD, Scadeng M, Dubowitz DJ, Crowston JG, Weinreb RN. Magnetic resonance imaging of the visual system in vivo: Transsynaptic illumination of V1 and V2 visual cortex. Neuroimage 2007; 34:1619-26. [PMID: 17204432 DOI: 10.1016/j.neuroimage.2006.07.048] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2005] [Revised: 07/12/2006] [Accepted: 07/12/2006] [Indexed: 10/23/2022] Open
Abstract
Brain nuclei directly receiving retinal projections are readily labeled in magnetic resonance images following intraocular injection of manganese (Mn). To assess whether Mn in retinal ganglion cell axons can be transsynaptically delivered to visual cortex, mice that had previously received intraocular Mn injection were anesthetized with isoflurane, and T1-weighted data sets were acquired of the eyes and brain using a 7-T magnetic resonance imaging machine. Image intensity within contralateral brain structures was evaluated by assessing 1) signal-to-noise ratios, 2) mean image intensity, and 3) mean image intensity normalized to facial muscle intensity. Image intensity was increased throughout the visual pathway including within contralateral visual cortex areas V1 and V2L. Mean normalized image intensity was greater by 53% in the ipsilateral optic nerve and by 31% and 28% in the contralateral lateral geniculate nucleus and superior colliculus, respectively (N=5, P<0.02, paired t test). In contralateral visual cortex areas V1 and V2L, image intensity was increased by 7.5% and 6.8%, respectively (P<0.02 for both, paired t test). Power analysis of the different evaluation methods yielded evidence of superior sensitivity using the normalization method. Reconstruction of the visual system based upon threshold analysis allowed simultaneous visualization of all portions of the major retinal projections to the brain. These results support use of high magnetic field MRI imaging and data normalization for in vivo quantitative analysis of the mouse brain visual system including visual cortex.
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Affiliation(s)
- James D Lindsey
- Sophie and Arthur Brody Optic Nerve Laboratory, Hamilton Glaucoma Center, Department of Ophthalmology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0946, USA.
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Ranta VP, Urtti A. Transscleral drug delivery to the posterior eye: prospects of pharmacokinetic modeling. Adv Drug Deliv Rev 2006; 58:1164-81. [PMID: 17069929 DOI: 10.1016/j.addr.2006.07.025] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Accepted: 07/31/2006] [Indexed: 01/12/2023]
Abstract
Basic biological research has provided new approaches to treat severe diseases of the retina and choroid, such as age related macular degeneration. Although it is possible to deliver drugs from a subconjunctival drug depot to the retina and choroid, the barriers and kinetics of this route of drug administration are not well known. In this review we investigate the pharmacokinetic aspects of transscleral drug delivery into the posterior eye with emphasis on pharmacokinetic modeling. The existing simulation models related to the transscleral drug delivery are reviewed and future directions for the model development are discussed. In addition, a new simulation model for the transscleral drug delivery based on permeability data is introduced. This compartmental model contains several ocular tissues (sclera, choroid, retinal pigment epithelium and vitreous) and it takes into account the clearance of the drug via choroidal circulation. The model is used to simulate the vitreous delivery of macromolecules based on the available data on FITC-dextran 70 kDa.
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Affiliation(s)
- Veli-Pekka Ranta
- Department of Pharmaceutics, University of Kuopio, FIN-70211 Kuopio, Finland.
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Abstract
Drug delivery to the eye is hampered by anatomical factors, including the corneal epithelium, the blood-aqueous barrier and the blood-retinal barrier. This review aims to outline the major routes of ocular drug delivery, including systemic, topical, periocular and intravitreal. The pharmacokinetics, the disadvantages and the clinical relevance of these drug delivery routes have been emphasised. Recent advances in surgical techniques, therapeutic approaches and material sciences have produced exciting new therapies for ocular diseases. The role of ophthalmic drug formulation in targeting the desired ocular tissue and enhancing drug delivery by the chosen route whilst minimising side effects is also discussed.
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Affiliation(s)
- Deepta Ghate
- Emory University Eye Center, 1365B, Clifton Road, Atlanta, GA 30322, USA
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Abstract
Despite numerous scientific efforts, delivery of therapeutic amounts of a drug to the retina remains a challenge. This challenge is compounded if chronic therapy is desired. The inability or inefficiency of topical and systemic routes for retinal delivery of existing drugs is now widely accepted. Although the intravitreal route offers high local concentrations in the vitreous and, hence, retina, these advantages are offset by side effects, such as cataracts, endophthalmitis and retinal detachment, following repeated intravitreal injections, or intravitreal placement of sustained-release implants. As discussed in this review, periocular routes, including subconjunctival, sub-tenon, retrobulbar, peribulbar and posterior juxtascleral routes, potentially offer a more promising alternative for enhanced drug delivery to the retina compared with topical and systemic routes. Periocular routes exploit the permeability of sclera for retinal drug delivery, and they are particularly useful for administering sustained-release systems of potent drugs. This review discusses the various periocular routes with respect to their anatomical location, pharmacokinetics, safety and mechanisms of drug delivery. In the coming years, several innovations in absorption enhancement, drug delivery systems and drug administration devices are anticipated for improving retinal drug delivery via periocular routes.
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Affiliation(s)
- Swita Raghava
- University of Nebraska Medical Centre, Department of Pharmaceutical Sciences, Omaha, NE 68198-5840, USA
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Li SK, Molokhia SA, Jeong EK. Assessment of subconjunctival delivery with model ionic permeants and magnetic resonance imaging. Pharm Res 2005; 21:2175-84. [PMID: 15648248 DOI: 10.1007/s11095-004-7669-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE The objective was to assess the permeation and clearance of model ionic permeants after subconjunctival injection with nuclear magnetic resonance imaging (MRI). METHODS New Zealand white rabbit was the animal model and manganese ion (Mn2+) and manganese ethylenediaminetetraacetic acid complex (MnEDTA2-) were the model permeants. The current study was divided into three parts: in vitro, postmortem, and in vivo. Transscleral passive permeation experiments were conducted with excised sclera in side-by-side diffusion cells in vitro. Subconjunctival delivery experiments were conducted with rabbits postmortem and in vivo. The distribution and elimination of the probe permeants from the subconjunctival space after subconjunctival injections were determined by MRI. RESULTS The data of excised sclera in vitro suggest large effective pore size for transscleral transport and negligible pore charge effects upon the permeation of the ionic permeants. The permeability coefficients of Mn2+ and MnEDTA2- across the sclera in vitro were 3.6 x 10(-5) cm/s and 2.4 x 10(-5) cm/s, respectively. Although relatively high sclera permeability was observed in vitro, subconjunctival injections in vivo did not provide significant penetration of Mn2+ and MnEDTA2- into the globe; permeant concentrations in the eye were below the detection limit, which corresponds to less than 0.05% of the concentration of the injection solution (e.g., less than 0.02 mM when 40 mM injection solution was used). The volume of the subconjunctival pocket and the concentration of the permeants in the pocket were observed to decrease with time after the injection, and this could contribute to the lower than expected subconjunctival absorption in vivo. Different from the results in vivo, experiments with rabbits postmortem show significant penetration of Mn2+ and MnEDTA2- into the globe with the permeants primarily delivered into the anterior segment of the eye. This difference suggests blood vasculature clearance as a main barrier for passive transscleral transport. The data also show that the pars plicata/pars plana is the least resistance pathway for passive transscleral drug delivery of the polar permeants, and there are indications of the presence of another barrier, possibly the retinal epithelium and/or Bruch's membrane, at the back of the eye. CONCLUSIONS Subconjunctival delivery of the ionic permeants in vivo cannot be quantitatively predicted by the in vitro results. MRI is a noninvasive complementary technique to traditional pharmacokinetic methods. It can provide insights into ocular pharmacokinetics without permeant redistribution that can occur in surgical procedure postmortem in traditional pharmacokinetic studies when the blood vasculature barrier is absent.
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Affiliation(s)
- S Kevin Li
- Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112, USA.
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Abstract
This review outlines the applications of liposomal formulations in ophthalmology. In ophthalmology, liposomes have been used to treat disorders of both the anterior and posterior segments. These include dry eyes, keratitis, corneal transplant rejection, uveitis, endophthalmitis, and proliferative vitreoretinopathy. Liposomes also have shown promise as vectors for genetic transfection and monoclonal antibody-directed vehicles. Furthermore, heat-activated liposomes have spurred research in focal laser and heat-induced release of liposomal drugs and dyes for selective drug delivery. These techniques have been useful in selective tumor and neovascular vessel occlusion, angiography, and retinal and choroidal blood-flow studies. Although verteporfin is the only liposomal drug currently approved for use in the eye, the benefits of liposomes will likely be applied widely in all treatment, diagnostic, and research aspects of ophthalmology in the future.
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Affiliation(s)
- Shehab Ebrahim
- Department of Ophthalmology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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Ayalasomayajula SP, Kompella UB. Retinal delivery of celecoxib is several-fold higher following subconjunctival administration compared to systemic administration. Pharm Res 2005; 21:1797-804. [PMID: 15553225 DOI: 10.1023/b:pham.0000045231.51924.e8] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE We have previously demonstrated that celecoxib, a selective COX-2 inhibitor, reaches the retina following repeated oral administrations and inhibits diabetes-induced vascular endothelial growth factor (VEGF) mRNA expression and vascular leakage in a rat model. The aim of this study was to quantify the relative retinal bioavailability of celecoxib from the subconjunctival route compared to a systemic route. METHODS The plasma and ocular tissue distribution of celecoxib was determined in male Sprague-Dawley rats following subconjunctival and intraperitoneal administrations of drug suspension at a dose of 3 mg/rat. The animals were sacrificed at 0.5, 1, 2, 3, 4, 8, and 12 h post-dosing, the blood was collected, and the eyes were enucleated and frozen. The plasma, sclera, retina, vitreous, lens, and the cornea were isolated and celecoxib levels were determined using an HPLC method. The tissue exposure of the drug was measured as the area under the curve (AUC(0-infinity)) of the concentration vs. time profiles. The relative bioavailability was estimated as the AUC(0-infinity) ratio between subconjunctival and intraperitoneal groups. RESULTS For the subconjunctivally dosed (ipsilateral) eye, the AUC(0-infinity) ratios between subconjunctival and intraperitoneal groups were 0.8 +/- 0.1, 53 +/- 4, 54 +/- 8, 145 +/- 21, 61 +/- 16, and 52 +/- 6 for plasma, sclera, retina, vitreous, lens, and cornea, respectively. For the contralateral ocular tissues, the AUC0-infinity ratios were 1.2 +/- 03, 11 +/- 0.3, 1.1 +/- 0.4, 1.0 +/- 0.3, and 1.2 +/- 0.3 in the sclera, retina, vitreous, lens, and the cornea, respectively, between the subconjunctival and the intraperitoneal groups. Assuming that the drug AUCs in contralateral eye were equal to the systemic pathway contribution to AUCs in the ipsilateral eye, the percent contribution of local pathways as opposed to systemic circulation for celecoxib delivery to the ipsilateral eye tissues was estimated to be 98% or greater. CONCLUSIONS The retinal delivery of celecoxib was substantially higher following subconjunctival administration compared to the intraperitoneal route. The transscleral pathway almost completely accounts for the retinal celecoxib delivery following subconjunctival administration.
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Affiliation(s)
- Surya P Ayalasomayajula
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Lee TWY, Robinson JR. Drug delivery to the posterior segment of the eye II: development and validation of a simple pharmacokinetic model for subconjunctival injection. J Ocul Pharmacol Ther 2004; 20:43-53. [PMID: 15006158 DOI: 10.1089/108076804772745455] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The aim of this study was to develop and validate a simple pharmacokinetic model for subconjunctival injection so as to study drug delivery to the posterior segment of the eye using the subconjunctival route. Curve-fitting was performed by ModelMaker 4.0 by applying Tsuji et al.'s in vivo data. It was found that drug elimination from the vitreous chamber was slowed by the existence of a peripheral compartment. The validity of this model was ensured because it gives reasonable predictability at two additional doses. This model is invaluable in studying drug delivery to the back of the eye by subconjunctival injection.
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Affiliation(s)
- Thomas Wai-Yip Lee
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53075, USA
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Abstract
The published evidence that instilled drugs can affect the blood supply to the retina and optic nerve head in humans is examined. As a background, seven techniques that have been used to measure flow are briefly described and criticized. For timolol, the corresponding measurements, obtained by a number of investigators are evaluated. The outcome is very erratic and does not allow any conclusion as to the effect of this drug on flow. Consideration is then given to the possible mechanism whereby a drug could affect blood flow; directly, by diffusion to receptors on the vessels, or indirectly, through more anterior receptors. The question is raised whether the small changes in circulation induced by drugs would not be swamped by those resulting from natural alterations in the ambient light level. The literature was analyzed in the hope of identifying discrete entry pathways, for example, through the lens or the suprachoroidal space, that are sufficiently permeable to allow a significant quantity of drug to pass. There was an indication that a drug might diffuse through the lens cortex in sufficient quantity to cause a measurable rise in its concentration in the vitreous. In general, however, there was insufficient quantitative data to allow any meaningful predictions to be made. Stimulated by recent evidence, it is suggested that drug penetration from the tear fluid takes place by direct diffusion across the conjunctiva into the sclera and orbit when the head is supine.
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Affiliation(s)
- David M Maurice
- Department of Ophthalmology, Columbia University, 630 West 168th Street, New York, NY 10032, USA.
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