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Annuryanti F, Domínguez-Robles J, Anjani QK, Adrianto MF, Larrañeta E, Thakur RRS. Fabrication and Characterisation of 3D-Printed Triamcinolone Acetonide-Loaded Polycaprolactone-Based Ocular Implants. Pharmaceutics 2023; 15:243. [PMID: 36678872 PMCID: PMC9863928 DOI: 10.3390/pharmaceutics15010243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/13/2022] [Accepted: 12/26/2022] [Indexed: 01/13/2023] Open
Abstract
Triamcinolone acetonide (TA) is a corticosteroid that has been used to treat posterior segment eye diseases. TA is injected intravitreally in the management of neovascular disorders; however, frequent intravitreal injections result in many potential side effects and poor patient compliance. In this work, a 3D bioprinter was used to prepare polycaprolactone (PCL) implants loaded with TA. Implants were manufactured with different shapes (filament-, rectangular-, and circle-shaped) and drug loadings (5, 10, and 20%). The characterisation results showed that TA was successfully mixed and incorporated within the PCL matrix without using solvents, and drug content reached almost 100% for all formulations. The drug release data demonstrate that the filament-shaped implants (SA/V ratio~7.3) showed the highest cumulative drug release amongst all implant shapes over 180 days, followed by rectangular- (SA/V ratio~3.7) and circle-shaped implants (SA/V ratio~2.80). Most implant drug release data best fit the Korsmeyer−Peppas model, indicating that diffusion was the prominent release mechanism. Additionally, a biocompatibility study was performed; the results showed >90% cell viability, thus proving that the TA-loaded PCL implants were safe for ocular application.
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Affiliation(s)
- Febri Annuryanti
- Medical Biology Centre, School of Pharmacy, Queen’s University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
- Faculty of Pharmacy, Airlangga University, Nanizar Zaman Joenoes Building, C Campus, Mulyorejo, Surabaya 60115, Indonesia
| | - Juan Domínguez-Robles
- Medical Biology Centre, School of Pharmacy, Queen’s University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Qonita Kurnia Anjani
- Medical Biology Centre, School of Pharmacy, Queen’s University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Muhammad Faris Adrianto
- Medical Biology Centre, School of Pharmacy, Queen’s University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
- Faculty of Pharmacy, Airlangga University, Nanizar Zaman Joenoes Building, C Campus, Mulyorejo, Surabaya 60115, Indonesia
| | - Eneko Larrañeta
- Medical Biology Centre, School of Pharmacy, Queen’s University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Raghu Raj Singh Thakur
- Medical Biology Centre, School of Pharmacy, Queen’s University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
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Bufton J, Jung S, Evans JC, Bao Z, Aguiar D, Allen C. Cross-linked valerolactone copolymer implants with tailorable biodegradation, loading and in vitro release of paclitaxel. Eur J Pharm Sci 2021; 162:105808. [DOI: 10.1016/j.ejps.2021.105808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/18/2021] [Accepted: 03/11/2021] [Indexed: 12/20/2022]
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García-Estrada P, García-Bon MA, López-Naranjo EJ, Basaldúa-Pérez DN, Santos A, Navarro-Partida J. Polymeric Implants for the Treatment of Intraocular Eye Diseases: Trends in Biodegradable and Non-Biodegradable Materials. Pharmaceutics 2021; 13:701. [PMID: 34065798 PMCID: PMC8151640 DOI: 10.3390/pharmaceutics13050701] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 12/15/2022] Open
Abstract
Intraocular/Intravitreal implants constitute a relatively new method to treat eye diseases successfully due to the possibility of releasing drugs in a controlled and prolonged way. This particularity has made this kind of method preferred over other methods such as intravitreal injections or eye drops. However, there are some risks and complications associated with the use of eye implants, the body response being the most important. Therefore, material selection is a crucial factor to be considered for patient care since implant acceptance is closely related to the physical and chemical properties of the material from which the device is made. In this regard, there are two major categories of materials used in the development of eye implants: non-biodegradables and biodegradables. Although non-biodegradable implants are able to work as drug reservoirs, their surgical requirements make them uncomfortable and invasive for the patient and may put the eyeball at risk. Therefore, it would be expected that the human body responds better when treated with biodegradable implants due to their inherent nature and fewer surgical concerns. Thus, this review provides a summary and discussion of the most common non-biodegradable and biodegradable materials employed for the development of experimental and commercially available ocular delivery implants.
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Affiliation(s)
- Paulina García-Estrada
- Departamento de Ingenieria de Proyectos-CUCEI, Universidad de Guadalajara, C.P. 45157 Zapopan, Mexico; (P.G.-E.); (M.A.G.-B.); (E.J.L.-N.); (D.N.B.-P.)
| | - Miguel A. García-Bon
- Departamento de Ingenieria de Proyectos-CUCEI, Universidad de Guadalajara, C.P. 45157 Zapopan, Mexico; (P.G.-E.); (M.A.G.-B.); (E.J.L.-N.); (D.N.B.-P.)
| | - Edgar J. López-Naranjo
- Departamento de Ingenieria de Proyectos-CUCEI, Universidad de Guadalajara, C.P. 45157 Zapopan, Mexico; (P.G.-E.); (M.A.G.-B.); (E.J.L.-N.); (D.N.B.-P.)
| | - Dulce N. Basaldúa-Pérez
- Departamento de Ingenieria de Proyectos-CUCEI, Universidad de Guadalajara, C.P. 45157 Zapopan, Mexico; (P.G.-E.); (M.A.G.-B.); (E.J.L.-N.); (D.N.B.-P.)
| | - Arturo Santos
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Campus Guadalajara, C.P. 45138 Zapopan, Mexico;
| | - Jose Navarro-Partida
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Campus Guadalajara, C.P. 45138 Zapopan, Mexico;
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Won JY, Kim J, Gao G, Kim J, Jang J, Park YH, Cho DW. 3D printing of drug-loaded multi-shell rods for local delivery of bevacizumab and dexamethasone: A synergetic therapy for retinal vascular diseases. Acta Biomater 2020; 116:174-185. [PMID: 32927088 DOI: 10.1016/j.actbio.2020.09.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/21/2020] [Accepted: 09/03/2020] [Indexed: 12/16/2022]
Abstract
The clinical therapy for retinal vascular diseases requires repeated intravitreal injections of drugs owing to their short half-life, which imposes health and economic burdens on patients. Therefore, it is necessary to develop an advanced drug delivery system that can prolong the drug activity and minimize secondary complications. In this study, we developed a core/shell drug-loaded rod (drug rod) to deliver two types of drugs (bevacizumab (BEV) and dexamethasone (DEX)) from a single implant. The coaxial printing technique allowed BEV and DEX to be released with different kinetics at the same site by using a polymeric shell and a hydrogel core, respectively. The suggested printing technique facilitates the production of drug rods with various dimensions and drug concentrations, and the multi-layered design allows to adjust the release profile of dual drug-delivery system. The rod was injected in rat vitreous less invasively using a small-gauge needle. Further, we validated the efficacy of the implanted drug rods in inhibiting inflammatory responses and long-term suppression of neovascularization compared to the conventional intravitreal injection of BEV in animal model, indicating that the drug rods can be an alternative therapeutic approach for the treatment of various types of retinal vascular diseases.
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Affiliation(s)
- Jae Yon Won
- Department of Ophthalmology and Visual Science, Eunpyeong St. Mary's Hospital, The Catholic University of Korea, South Korea; Catholic Institute for Visual Science, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Jisoo Kim
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), Pohang, South Korea
| | - Ge Gao
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, South Korea
| | - Jongmin Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, South Korea
| | - Jinah Jang
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), Pohang, South Korea; Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, South Korea; Department of Creative IT Engineering, Pohang University of Science and Technology (POSTECH), Pohang, South Korea
| | - Young-Hoon Park
- Catholic Institute for Visual Science, College of Medicine, The Catholic University of Korea, Seoul, South Korea; Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea.
| | - Dong-Woo Cho
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), Pohang, South Korea; Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, South Korea.
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Boia R, Dias PA, Martins JM, Galindo-Romero C, Aires ID, Vidal-Sanz M, Agudo-Barriuso M, de Sousa HC, Ambrósio AF, Braga ME, Santiago AR. Porous poly(ε-caprolactone) implants: A novel strategy for efficient intraocular drug delivery. J Control Release 2019; 316:331-348. [DOI: 10.1016/j.jconrel.2019.09.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 09/26/2019] [Accepted: 09/29/2019] [Indexed: 01/22/2023]
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Nekouian S, Sojoodi M, Nadri S. Fabrication of conductive fibrous scaffold for photoreceptor differentiation of mesenchymal stem cell. J Cell Physiol 2019; 234:15800-15808. [PMID: 30714142 DOI: 10.1002/jcp.28238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/23/2018] [Accepted: 11/30/2018] [Indexed: 01/24/2023]
Abstract
Conductive nanofibrous scaffolds with that can conduct electrical current have a great potential in neural tissue engineering. The purpose of this study was to survey effects of electrical stimulation and polycaprolactone/polypyrrole/multiwall carbon nanotube (PCL/PPY/MWCNTs) fibrous scaffold on photoreceptor differentiation of trabecular meshwork mesenchymal stem cells (TM-MSCs). PCL/PPY/MWCNTs scaffold was made by electrospinning method. TM-MSCs were seeded on PCL/PPY/MWCNTs scaffold and stimulated with a potential of 115 V/m. Scanning electron microscopy, transmission electron microscopy, and FT-IR were used to evaluate the fabricated scaffold. Immunofluorescence and quantitative real-time polymerase chain reaction were used to examine differentiated cells. Scanning electron microscopy, transmitting electron microscopy, and FT-IR confirmed the creation of the composite structure of fibers. RT-qPCR analysis showed that the expression of rhodopsin and peripherin genes in electrically stimulated cells were significantly higher (5.7- and 6.23-fold, respectively; p ≤ 0.05) than those with no electrical stimulation. Collectively, it seems that the combination of PCL/PPY/MWCNTs scaffold, as a suitable conductive scaffold, and electrical stimulation could be an effective approach in the differentiation of stem cells in retinal tissue engineering.
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Affiliation(s)
- Soraya Nekouian
- Department of Medical Nanotechnology, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Mahdi Sojoodi
- Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, Iran
| | - Samad Nadri
- Department of Medical Nanotechnology, Zanjan University of Medical Sciences, Zanjan, Iran.,Zanjan Metabolic Diseases Research Center, Zanjan University of Medical Sciences, Zanjan, Iran.,Zanjan Pharmaceutical Nanotechnology Research Center, Zanjan University of Medical Sciences, Zanjan, Iran
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Dang HP, Shabab T, Shafiee A, Peiffer QC, Fox K, Tran N, Dargaville TR, Hutmacher DW, Tran PA. 3D printed dual macro-, microscale porous network as a tissue engineering scaffold with drug delivering function. Biofabrication 2019; 11:035014. [PMID: 30933941 DOI: 10.1088/1758-5090/ab14ff] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Tissue engineering macroporous scaffolds are important for regeneration of large volume defects resulting from diseases such as breast or bone cancers. Another important part of the treatment of these conditions is adjuvant drug therapy to prevent disease recurrence or surgical site infection. In this study, we developed a new type of macroporous scaffolds that have drug loading and release functionality to use in these scenarios. 3D printing allows for building macroporous scaffolds with deterministically designed complex architectures for tissue engineering yet they often have low surface areas thus limiting their drug loading capability. In this proof-of-concept study, we aimed to introduce microscale porosity into macroporous scaffolds to allow for efficient yet simple soak-loading of various clinical drugs and control their release. Manufacturing of scaffolds having both macroporosity and microscale porosity remains a difficult task. Here, we combined porogen leaching and 3D printing to achieve this goal. Porogen microparticles were mixed with medical grade polycaprolactone and extruded into scaffolds having macropores of 0.7 mm in size. After leaching, intra-strut microscale pores were realized with pore size of 20-70 μm and a total microscale porosity of nearly 40%. Doxorubicin (DOX), paclitaxel (PTX) and cefazolin (CEF) were chosen as model drugs of different charges and solubilities to soak-load the scaffolds and achieved loading efficiency of over 80%. The microscale porosity was found to significantly reduce the burst release allowing the microporous scaffolds to release drugs up to 200, 500 and 150 h for DOX, PTX and CEF, respectively. Finally, cell assays were used and confirmed the bioactivities and dose response of the drug-loaded scaffolds. Together, the findings from this proof-of-concept study demonstrate a new type of scaffolds with dual micro-, macro-porosity for tissue engineering applications with intrinsic capability for efficient loading and sustained release of drugs to prevent post-surgery complications.
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Affiliation(s)
- Hoang Phuc Dang
- ARC Centre in Additive Biomanufacturing, Queensland University of Technology (QUT), Brisbane, Queensland, Australia. Centre in Regenerative Medicine, Institute of Health and Biomedical Innovation, QUT, Brisbane, Queensland, Australia
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Volatile Acid-Solvent Evaporation (VASE): Molecularly Homogeneous Distribution of Acyclovir in a Bioerodable Polymer Matrix for Long-Term Treatment of Herpes Simplex Virus-1 Infections. JOURNAL OF DRUG DELIVERY 2018; 2018:6161230. [PMID: 30356432 PMCID: PMC6178155 DOI: 10.1155/2018/6161230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 06/07/2018] [Accepted: 09/03/2018] [Indexed: 11/19/2022]
Abstract
Treatment for herpes simplex virus-1 and -2 (HSV-1 and -2) patients who suffer from recurrent outbreaks consists of multiple daily doses of the antiviral drugs acyclovir (ACV), penciclovir, or their more orally bioavailable derivatives valacyclovir or famciclovir. Drug troughs caused by missed doses may result in viral replication, which can generate drug-resistant mutants along with clinical sequelae. We developed a molecularly homogeneous mixture of ACV with the bioerodable polymer polycaprolactone. Through scanning electron microscopy, infrared spectroscopy, gel permeation chromatography, 1H NMR, and differential scanning calorimetry, our method of combining drug and polymer, termed Volatile Acid-Solvent Evaporation (VASE), does not compromise the integrity of polymer or drug. Furthermore, VASE creates materials that deliver therapeutic amounts of drug consistently for approximately two months. Devices with high enough drug loads diminish primary infection of HSV-1 in Vero cells to the same level as seen with a single dose of ACV. Our data will lead to further experiments in animal models, demonstrating efficacy in preventing reactivation of these viruses with a single intervention, and with other antiviral drugs amenable to such manipulation. Additionally, this type of treatment would leave no trace after its useful lifetime, as drug is released and polymer matrix is degraded in vivo.
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Kim J, Kudisch M, Mudumba S, Asada H, Aya-Shibuya E, Bhisitkul RB, Desai TA. Biocompatibility and Pharmacokinetic Analysis of an Intracameral Polycaprolactone Drug Delivery Implant for Glaucoma. Invest Ophthalmol Vis Sci 2017; 57:4341-6. [PMID: 27556217 PMCID: PMC5015984 DOI: 10.1167/iovs.16-19585] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Purpose We developed polycaprolactone (PCL) implants that achieve zero-order release of a proprietary ocular hypotensive agent (DE-117) over 6 months. Methods The release rates of DE-117–loaded PCL devices were tuned based on an established predictive model and confirmed by in vitro release studies. Devices containing DE-117 and empty devices were implanted intracamerally in normotensive rabbits for up to 8 weeks' duration. Devices were retrieved after rabbits were euthanized and evaluated for tissue adherence. The drug remaining in each device was analyzed by high performance liquid chromatography. Drug distribution in ocular tissues was measured by liquid chromatography coupled with a tandem mass spectrometry (LC/MS/MS). Results In vitro release of DE-117 showed zero-order release with a release rate of 0.5 μg/day over 6 months. Implantation in rabbit eyes demonstrated that the devices were well tolerated in the intracameral space. Quantification of DE-117 and hDE-117 (the hydrolyzed active form of DE-117) in ocular tissues (cornea, iris-ciliary body, aqueous humor, and vitreous humor) indicated sustained release of DE-117 and its conversion to hDE-117 when released from the device. Analysis of drug remaining in the device found that concentration of hDE-117 was below the limit of detection, indicating the encapsulated drug was protected from hydrolysis in the device. Conclusions Proof-of-concept PCL drug delivery devices containing DE-117 show promise as a long-term glaucoma treatment based on their zero-order drug release profile in vitro, biocompatibility in vivo, and effective distribution of released drug in relevant ocular tissues.
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Affiliation(s)
- Jean Kim
- UCB-UCSF Graduate Program in Bioengineering, San Francisco, California, United States
| | - Max Kudisch
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Sri Mudumba
- Santen, Inc., Emeryville, California, United States
| | - Hiroyuki Asada
- Santen Pharmaceutical Co., Ltd., Nara RD Center, Nara, Japan
| | - Eri Aya-Shibuya
- Santen Pharmaceutical Co., Ltd., Nara RD Center, Nara, Japan
| | - Robert B Bhisitkul
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Tejal A Desai
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, United States
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Sharma AK, Arya A, Sahoo PK, Majumdar DK. Overview of biopolymers as carriers of antiphlogistic agents for treatment of diverse ocular inflammations. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 67:779-791. [PMID: 27287177 DOI: 10.1016/j.msec.2016.05.060] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 05/04/2016] [Accepted: 05/15/2016] [Indexed: 01/19/2023]
Abstract
Inflammation of the eye is a usual clinical condition that can implicate any part of the eye. The nomenclature of variety of such inflammations is based on the ocular part involved. These diseases may jeopardize normal functioning of the eye on progression. In general, corticosteroids, antihistamines, mast cell stabilizers and non-steroidal anti-inflammatory drugs (NSAIDs) are used to treat inflammatory diseases/disorders of the eye. There have been several attempts via different approaches of drug delivery to overcome the low ocular bioavailability resulting from shorter ocular residence time. The features like safety, ease of elimination and ability to sustain drug release have led to application of biopolymers in ocular therapeutics. Numerous polymers of natural origin such as gelatin, collagen, chitosan, albumin, hyaluronic acid, alginates etc. have been successfully employed for preparation of different ocular dosage forms. Chitosan is the most explored biopolymer amongst natural biopolymers because of its inherent characteristics. The emergence of synthetic biopolymers (like PVP, PACA, PCL, POE, polyanhydrides, PLA, PGA and PLGA) has also added new dimensions to the drug delivery strategies meant for treatment of ophthalmic inflammations. The current review is an endeavor to describe the utility of a variety of biomaterials/polymers based drug delivery systems as carrier for anti-inflammatory drugs in ophthalmic therapeutics.
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Affiliation(s)
- Anil Kumar Sharma
- Delhi Institute of Pharmaceutical Sciences and Research, Formerly College of Pharmacy, University of Delhi, Pushp Vihar, Sector III, New Delhi 110017,India.
| | - Amit Arya
- Delhi Institute of Pharmaceutical Sciences and Research, Formerly College of Pharmacy, University of Delhi, Pushp Vihar, Sector III, New Delhi 110017,India
| | - Pravat Kumar Sahoo
- Delhi Institute of Pharmaceutical Sciences and Research, Formerly College of Pharmacy, University of Delhi, Pushp Vihar, Sector III, New Delhi 110017,India
| | - Dipak Kanti Majumdar
- School of Pharmaceutical Sciences, Apeejay Stya University, Sohna-Palwal Road, Gurgaon 122103, India
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Yazici A, Ozdal PC. Intravitreal drug administration for treatment of noninfectious uveitis. World J Ophthalmol 2015; 5:125-132. [DOI: 10.5318/wjo.v5.i3.125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/26/2015] [Accepted: 06/16/2015] [Indexed: 02/06/2023] Open
Abstract
Intravitreal treatment became popular with the discovery of the blood ocular barriers, which significantly limit drug penetration in systemic or topical administration. As the mainstay of treatment in noninfectious uveitis (NOIU) is still corticosteroids, triamcinolone acetonide (TA) was the first intravitreally used agent in this subset of patients. Although it was very effective in controlling inflammation and improving the inflammation related complications, TA was found to have a high rate of intraocular complications and a relatively short half-life necessitating frequent reinjections. Other systemically used therapeutic options such as methotrexate and anti-tumor necrosis factor-α agents were also tried intravitreally. Additionally anti-vascular endothelial growth factor agents that are widely used intravitreally in the management of diabetic retinopathy and age related macular degeneration have become an option to control the uveitis related complications like macular edema, retinal and choroidal neovascularizations. Advances in biotechnology led to the slow release biodegradable implant era. These implants have a longer duration of action, which may help in decreasing the number of reinjections. Today two forms of implants have been approved for use in NOIU, Retisert (0.59 mg flucinolone acetonide, surgical intervention) and Ozurdex (0.7 mg dexamethasone, office based intervention). Studies dealing with newer agents (cyclosporine, LFG31, sirolimus) in the management of chronic NOIU are on the way. The search for ideal effective, safe and biocompatible intravitreal agents in the management of NOIU has not ended yet.
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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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Wang J, Jiang A, Joshi M, Christoforidis J. Drug delivery implants in the treatment of vitreous inflammation. Mediators Inflamm 2013; 2013:780634. [PMID: 24191132 PMCID: PMC3804444 DOI: 10.1155/2013/780634] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 09/06/2013] [Indexed: 11/25/2022] Open
Abstract
The eye is a model organ for the local delivery of therapeutics. This proves beneficial when treating vitreous inflammation and other ophthalmic pathologies. The chronicity of certain diseases, however, limits the effectiveness of locally administered drugs. To maintain such treatments often requires frequent office visits and can result in increased risk of infection and toxicity to the patient. This paper focuses on the implantable devices and particulate drug delivery systems that are currently being implemented and investigated to overcome these challenges. Implants currently on the market or undergoing clinical trials include those made of nonbiodegradable polymers, containing ganciclovir, fluocinolone acetonide, triamcinolone acetonide, and ranibizumab, and biodegradable polymers, containing dexamethasone, triamcinolone acetonide, and ranibizumab. Investigational intravitreal implants and particulate drug delivery systems, such as nanoparticles, microparticles, and liposomes, are also explored in this review article.
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Affiliation(s)
- Jillian Wang
- Department of Ophthalmology, The Ohio State University Wexner Medical Center, 915 Olentangy River Road, Suite 5000, Columbus, OH 43212, USA
| | - Angela Jiang
- Department of Ophthalmology, The Ohio State University Wexner Medical Center, 915 Olentangy River Road, Suite 5000, Columbus, OH 43212, USA
| | - Malav Joshi
- Department of Ophthalmology & Visual Science, The University of Arizona Medical Center, 655 N. Alvernon Way, Suite 108, Tucson, AZ 85711, USA
| | - John Christoforidis
- Department of Ophthalmology & Visual Science, The University of Arizona Medical Center, 655 N. Alvernon Way, Suite 108, Tucson, AZ 85711, USA
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Bernards DA, Bhisitkul RB, Wynn P, Steedman MR, Lee OT, Wong F, Thoongsuwan S, Desai TA. Ocular biocompatibility and structural integrity of micro- and nanostructured poly(caprolactone) films. J Ocul Pharmacol Ther 2013; 29:249-57. [PMID: 23391326 DOI: 10.1089/jop.2012.0152] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The identification of biomaterials that are well tolerated in the eye is important for the development of new ocular drug delivery devices and implants, and the application of micro- and nanoengineered devices to biomedical treatments is predicated on the long-term preservation within the target organ or tissue of the very small functional design elements. This study assesses the ocular tolerance and durability of micro- and nanostructured biopolymer thin films injected or implanted into the rabbit eye. Structured poly(caprolactone) (PCL) thin films were placed in adult rabbit eyes for survival studies, with serial ophthalmic examinations over 6 months. Morphologic abnormalities and device/tissue reactions were evaluated by histologic studies, and scanning electron microscopy (SEM) of films was used to determine the structural integrity. Structured PCL thin films (20- to 40-μm thick) were constructed to design specifications with 50-μm linear microgrooves or arrays of nanopores with ~30-nm diameters. After up to 9 months of ocular residency, SEM on devices retrieved from the eye showed preservation of micro- and nanostructural features. In ocular safety evaluations carried out over 6 months, serial examinations in 18 implanted eyes showed no evidence of chronic inflammation, cataractogenesis, or retinal toxicity. Postoperative ocular inflammation was seen in 67% of eyes for 1 week, and persistent corneal edema occurred in 1 eye. Histology revealed no ocular inflammation or morphologic abnormalities of ocular tissues. Thin-film/tissue responses such as cellular reaction, fibrosis, or surface biodeposits were not seen. Micro- and nanostructured PCL thin films exhibited acceptable ocular tolerance and maintained the structural integrity of design features while residing in the eye. Thin-film micro- and nanostructured PCL appears to be a feasible biomaterial for intraocular therapeutic applications.
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Affiliation(s)
- Daniel A Bernards
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
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Intravitreal devices for the treatment of vitreous inflammation. Mediators Inflamm 2012; 2012:126463. [PMID: 22988344 PMCID: PMC3441042 DOI: 10.1155/2012/126463] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 07/31/2012] [Indexed: 12/03/2022] Open
Abstract
The eye is a well-suited organ for local delivery of therapeutics to treat vitreous inflammation as well as other pathologic conditions that induce visual loss. Several conditions are particularly challenging to treat and often require chronic courses of therapy. The use of implantable intravitreal devices for drug delivery is an emerging field in the treatment of vitreous inflammation as well as other ophthalmologic diseases. There are unique challenges in the design of these devices which include implants, polymers, and micro- and nanoparticles. This paper reviews current and investigational drug delivery systems for treating vitreous inflammation as well as other pathologic conditions that induce visual loss. The use of nonbiodegradable devices such as polyvinyl alcohol-ethylene vinyl acetate polymers and polysulfone capillary fibers, and biodegradable devices such as polylactic acid, polyglycolic acid, and polylactic-co-glycolic acid, polycaprolactones, and polyanhydrides are reviewed. Clinically used implantable devices for therapeutic agents including ganciclovir, fluocinolone acetonide, triamcinolone acetonide, and dexamethasone are described. Finally, recently developed investigational particulate drug delivery systems in the form of liposomes, microspheres, and nanoparticles are examined.
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Thrimawithana T, Rupenthal I, Young S, Alany R. Environment-sensitive polymers for ophthalmic drug delivery. J Drug Deliv Sci Technol 2012. [DOI: 10.1016/s1773-2247(12)50015-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Intraocular pressure changes: an important determinant of the biocompatibility of intravitreous implants. PLoS One 2011; 6:e28720. [PMID: 22194895 PMCID: PMC3237488 DOI: 10.1371/journal.pone.0028720] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 11/14/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In recent years, research efforts exploring the possibility of using biomaterial nanoparticles for intravitreous drug delivery has increased significantly. However, little is known about the effect of material properties on intravitreous tissue responses. PRINCIPAL FINDINGS To find the answer, nanoparticles made of hyaluronic acid (HA), poly (l-lactic acid) (PLLA), polystyrene (PS), and Poly N-isopropyl acrylamide (PNIPAM) were tested using intravitreous rabbit implantation model. Shortly after implantation, we found that most of the implants accumulated in the trabecular meshwork area followed by clearance from the vitreous. Interestingly, substantial reduction of intraocular pressure (IOP) was observed in eyes implanted with particles made of PS, PNIPAM and PLLA, but not HA nanoparticles and buffered salt solution control. On the other hand, based on histology, we found that the particle implantation had no influence on cornea, iris and even retina. Surprisingly, substantial CD11b+ inflammatory cells were found to accumulate in the trabecular meshwork area in some animals. In addition, there was a good relationship between recruited CD11b+ cells and IOP reduction. CONCLUSIONS Overall, the results reveal the potential influence of nanoparticle material properties on IOP reduction and inflammatory responses in trabecular meshwork. Such interactions may be critical for the development of future ocular nanodevices with improved safety and perhaps efficacy.
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Ang M, Yan P, Zhen M, Foo S, Venkatraman SS, Wong TT. Evaluation of sustained release of PLC-loaded prednisolone acetate microfilm on postoperative inflammation in an experimental model of glaucoma filtration surgery. Curr Eye Res 2011; 36:1123-8. [PMID: 22007761 DOI: 10.3109/02713683.2011.627489] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To evaluate the effect of a biodegradable microfilm with sustained release of prednisolone acetate (PA) on postoperative wound healing after experimental glaucoma filtration surgery (GFS). METHODS Biodegradable microfilms composed of poly (D-, L-lactide-co-caprolactone) (PLC) were fabricated and then pre-loaded PA-20% total weight. Fourteen New Zealand White rabbits were randomly divided into 3 treatment groups: GFS alone (n=4), GFS with PLC microfilms (n=4) and GFS with PA-loaded microfilm (n=6). Microfilms were inserted subconjunctivally, adjacent to the filtering surgical site. We monitored all eyes with slit-lamp examination, bleb photography and anterior segment optical coherence tomography (AS-OCT). Histology with immunohistochemistry was performed to determine the presence of any inflammation. RESULTS Prednisolone acetate 20%-loaded microfilms exhibited steady, sustained release in vitro. Eyes implanted with PA-loaded microfilms showed a significantly better bleb survival (100% vs. 37.5%, p<0.001) and reduced bleb vascularity (58%; 95% CI 54-62% vs. 30%; 95% CI 23-37%, p=0.001) compared to the control at 30 days postoperatively. Histology and immunohistochemistry demonstrated less T-cell infiltration in the eye implanted with PA-loaded microfilms. CONCLUSION Subconjunctival insertion of a PA-loaded biodegradeable microfilm exhibit sustained release of PA to reduce postoperative inflammation and prolong bleb survival in rabbit GFS.
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Affiliation(s)
- Marcus Ang
- Singapore National Eye Centre, Singapore
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Biocompatibility and biodegradation studies of subconjunctival implants in rabbit eyes. PLoS One 2011; 6:e22507. [PMID: 21799878 PMCID: PMC3142149 DOI: 10.1371/journal.pone.0022507] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 06/28/2011] [Indexed: 11/19/2022] Open
Abstract
Sustained ocular drug delivery is difficult to achieve. Most drugs have poor penetration due to the multiple physiological barriers of the eye and are rapidly cleared if applied topically. Biodegradable subconjunctival implants with controlled drug release may circumvent these two problems. In our study, two microfilms (poly [d,l-lactide-co-glycolide] PLGA and poly[d,l-lactide-co-caprolactone] PLC were developed and evaluated for their degradation behavior in vitro and in vivo. We also evaluated the biocompatibility of both microfilms. Eighteen eyes (9 rabbits) were surgically implanted with one type of microfilm in each eye. Serial anterior-segment optical coherence tomography (AS-OCT) scans together with serial slit-lamp microscopy allowed us to measure thickness and cross-sectional area of the microfilms. In vitro studies revealed bulk degradation kinetics for both microfilms, while in vivo studies demonstrated surface erosion kinetics. Serial slit-lamp microscopy revealed no significant inflammation or vascularization in both types of implants (mean increase in vascularity grade PLGA50/50 12±0.5% vs. PLC70/30 15±0.6%; P = 0.91) over a period of 6 months. Histology, immunohistochemistry and immuno-fluorescence also revealed no significant inflammatory reaction from either of the microfilms, which confirmed that both microfilms are biocompatible. The duration of the drug delivery can be tailored by selecting the materials, which have different degradation kinetics, to suit the desired clinical therapeutic application.
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Synthetic Polymer Scaffolds for Stem Cell Transplantation in Retinal Tissue Engineering. Polymers (Basel) 2011. [DOI: 10.3390/polym3020899] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Advances in Biodegradable Ocular Drug Delivery Systems. DRUG PRODUCT DEVELOPMENT FOR THE BACK OF THE EYE 2011. [DOI: 10.1007/978-1-4419-9920-7_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Blatsios G, Tzimas AS, Mattheolabakis G, Panagi Z, Avgoustakis K, Gartaganis SP. Development of Biodegradable Controlled Release Scleral Systems of Triamcinolone Acetonide. Curr Eye Res 2010; 35:916-24. [DOI: 10.3109/02713683.2010.497599] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Zarbin MA, Montemagno C, Leary JF, Ritch R. Nanomedicine in ophthalmology: the new frontier. Am J Ophthalmol 2010; 150:144-162.e2. [PMID: 20670739 DOI: 10.1016/j.ajo.2010.03.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 03/09/2010] [Accepted: 03/10/2010] [Indexed: 12/23/2022]
Abstract
PURPOSE To review the fields of nanotechnology and nanomedicine as they relate to the development of treatments for vision-threatening disorders. DESIGN Perspective following literature review. METHODS Analysis of relevant publications in the peer-reviewed scientific literature. RESULTS Nanotechnology involves the creation and use of materials and devices at the size scale of intracellular structures and molecules and involves systems and constructs on the order of <100 nm. The aim of nanomedicine is the comprehensive monitoring, control, construction, repair, defense, and improvement of human biological systems at the molecular level, using engineered nanodevices and nanostructures, operating massively in parallel at the single cell level, ultimately to achieve medical benefit. The earliest impact of nanomedicine is likely to involve the areas of biopharmaceuticals (eg, drug delivery, drug discovery), implantable materials (eg, tissue regeneration scaffolds, bioresorbable materials), implantable devices (eg, intraocular pressure monitors, glaucoma drainage valves), and diagnostic tools (eg, genetic testing, imaging, intraocular pressure monitoring). Nanotechnology will bring about the development of regenerative medicine (ie, replacement and improvement of cells, tissues, and organs), ultrahigh-resolution in vivo imaging, microsensors and feedback devices, and artificial vision. "Regenerative nanomedicine," a new subfield of nanomedicine, uses nanoparticles containing gene transcription factors and other modulating molecules that allow for the reprogramming of cells in vivo. CONCLUSIONS Nanotechnology already has been applied to the measurement and treatment of different disease states in ophthalmology (including early- and late-stage disease), and many additional innovations will occur during the next century.
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Enhanced differentiation of retinal progenitor cells using microfabricated topographical cues. Biomed Microdevices 2010; 12:363-9. [PMID: 20077017 PMCID: PMC2859162 DOI: 10.1007/s10544-009-9392-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Due to the retina’s inability to replace photoreceptors lost during retinal degeneration, significant interest has been placed in methods to implant replacement cells. Polymer scaffolds are increasingly being studied as vehicles for cellular delivery to degenerated retinas. Previously, we fabricated poly(methyl methacrylate) thin film scaffolds that increased survival and integration of implanted retinal progenitor cells (RPCs). Additionally, these scaffolds minimized the trauma and cellular response associated with implantation of foreign bodies into mouse eyes. Here, we demonstrate that biodegradable polycaprolactone (PCL) thin film scaffolds can be fabricated with integrated microtopography. Microfabricated topography in a PCL thin film enhanced the attachment and organization of RPCs compared to unstructured surfaces. Using real-time quantitative polymerase chain reaction we also observed that attachment to microtopography induced cellular differentiation. RPCs grown on PCL thin films exhibited an increase in gene expression for the photoreceptor markers recoverin and rhodopsin, an increase in the glial and Müller cell marker GFAP, and a decrease in SOX2 gene expression (a marker for undifferentiated progenitor cells) compared to cells grown on unmodified tissue culture polystyrene (TCPS).
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Intraocular sustained-release delivery systems for triamcinolone acetonide. Pharm Res 2009; 26:770-84. [PMID: 19184374 DOI: 10.1007/s11095-008-9812-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 12/11/2008] [Indexed: 02/06/2023]
Abstract
Recently, the use of triamcinolone acetonide (TA) injection has increased dramatically in treatment for several ocular diseases. Among them, macular diseases such as macular edema due to diabetic retinopathy, venous occlusive diseases, ocular inflammation and age-related macular degeneration (AMD) are very common vision threatening disorders and are great challenges to treat. In these types of chronic retinal diseases, repeated intraocular injections of TA are often required which increases the likelihood of complications. In order to achieve sustained-release, maintain therapeutic levels of TA over longer times and reduce frequency of intravitreal injections, researchers are investigating different implantable devices or injectable systems. However, as of yet, there is no sustained-release product for TA available on the commercial market. This review discusses and compares different sustained-release devices or injectable systems that are currently being developed.
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Subretinal injection of preservative-free triamcinolone acetonide and supernatant vehicle in rabbits: an electron microscopy study. Graefes Arch Clin Exp Ophthalmol 2007; 246:379-88. [DOI: 10.1007/s00417-007-0718-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2007] [Revised: 10/13/2007] [Accepted: 10/27/2007] [Indexed: 10/22/2022] Open
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Booth BA, Vidal Denham L, Bouhanik S, Jacob JT, Hill JM. Sustained-release ophthalmic drug delivery systems for treatment of macular disorders: present and future applications. Drugs Aging 2007; 24:581-602. [PMID: 17658909 DOI: 10.2165/00002512-200724070-00006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Macular disease currently poses the greatest threat to vision in aging populations. Historically, most of this pathology could only be dealt with surgically, and then only after much damage to the macula had already occurred. Current pathophysiological insights into macular diseases have allowed the development of effective new pharmacotherapies. The field of drug delivery systems has advanced over the last several years with emphasis placed on controlled release of drug to specific areas of the eye. Its unique location and tendency toward chronic disease make the macula an important and attractive target for drug delivery systems, especially sustained-release systems. This review evaluates the current literature on the research and development of sustained-release posterior segment drug delivery systems that are primarily intended for macular disease with an emphasis on age-related macular degeneration.Current effective therapies include corticosteroids and anti-vascular endothelial growth factor compounds. Recent successes have been reported using anti-angiogenic drugs for therapy of age-related macular degeneration. This review also includes information on implantable devices (biodegradable and non-biodegradable), the use of injected particles (microspheres and liposomes) and future enhanced drug delivery systems, such as ultrasound drug delivery. The devices reviewed show significant drug release over a period of days or weeks. However, macular disorders are chronic diseases requiring years of treatment. Currently, there is no 'gold standard' for therapy and/or drug delivery. Future studies will focus on improving the efficiency and effectiveness of drug delivery to the posterior chamber. If successful, therapeutic modalities will significantly delay loss of vision and improve the quality of life for patients with chronic macular disorders.
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Affiliation(s)
- Blake A Booth
- Department of Ophthalmology, LSU Health Sciences Center, New Orleans, Louisiana, USA
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Loftsson T, Hreinsdóttir D, Stefánsson E. Cyclodextrin microparticles for drug delivery to the posterior segment of the eye: aqueous dexamethasone eye drops. J Pharm Pharmacol 2007; 59:629-35. [PMID: 17524227 DOI: 10.1211/jpp.59.5.0002] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Delivery of steroids to the retina is currently undertaken with invasive injections into the vitreous cavity. This paper describes a non-invasive method to deliver steroids in therapeutic levels to the retina in rabbits. Dexamethasone was formulated as somewhat water-soluble dexamethasone/gamma-cyclodextrin (gammaCD) microparticles in a low-viscosity aqueous eye drop suspension. The mean (+/-standard deviation) diameter of the particles was 20.4+/-10.3 microm, with no particles larger than 60 microm. The aqueous suspension formulation was tested in rabbits and compared with an aqueous dexamethasone eye drop solution containing randomly methylated beta-cyclodextrin (RMbetaCD). The dexamethasone concentration was identical in both formulations (15 mg mL(-1)). The drug was administered to the left eye but determined in both eyes. The amount reaching different eye tissues via the topical route was determined by subtracting the amount found in the right eye from the amount found in the left eye. Two hours after single application of the dexamethasone/gammaCD eye drops to rabbits the mean (+/-s.d.) concentration in vitreous was 29+/-16 ng g(-1), 86% of which reached vitreous via the topical route and in retina the concentration was 57+/-22 ng g(-1) (49% via topical route). For the RMbetaCD the values were 22.6+/-9 and 66+/-49 ng g(-1) (73 and 14% via topical route), respectively. These steroid levels are comparable with the dexamethasone concentration achieved 1 month after intravitreal injection. The aqueous dexamethasone/gammaCD eye drop formulation was chemically stable during 7 months storage and well tolerated with no visible short-term side effects.
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Affiliation(s)
- Thorsteinn Loftsson
- Faculty of Pharmacy, University of Iceland, Hofsvallagata 53, IS-107 Reykjavik, Iceland.
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Kozak I, Cheng L, Falkenstein I, Tammewar AM, Freeman WR. Evaluation of Subretinal Triamcinolone Acetonide in Patients with Exudative Age-Related Macular Degeneration. J Ocul Pharmacol Ther 2007; 23:46-53. [PMID: 17341150 DOI: 10.1089/jop.2006.0092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE The aim of this paper was to present the results of subretinal delivery of triamcinolone acetonide (TCA) in humans with choroidal neovascularization (CNV) caused by age-related macular degeneration (AMD). METHODS Twenty two (22) eyes of 22 patients underwent pars plana vitrectomy with subretinal TCA administration. Two milligrams (2 mg) of preservative-free TCA were delivered through a 32-gauge automatic subretinal injector in 20 microL of volume. Visual acuity, fluorescein angiography (FA), and intraocular pressure (IOP) were recorded and compared pre- and postoperatively. RESULTS Preoperative average+/-standard deviation visual acuity in the treated eye was 1.408+/-0.129 (logMAR; median 20/400) and 1.403+/-0.114 (logMAR; median 20/300) postoperatively (P=0.51). The mean area of pre- and postoperative FA leakage in the operated eyes was 21.31+/-1.125 and 19.29+/-1.108 mm2, respectively (P=0.04). The average IOP value before treatment was 15.3+/-0.78 mmHg. Three (3) months after surgery, it was 20.5+/-2.04 mmHg (P=0.02). Six (6) months and 1 year after surgery, the average IOP was 17.0+/-0.66 mmHg (P=0.9) and 15.6+/-1.02 mmHg (P=0.6), respectively. CONCLUSIONS Subretinal TCA stabilizes visual acuity, decreases FA leakage in eyes with CNV owing to AMD, and does not increase IOP, as seen with intravitreous injections.
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Affiliation(s)
- Igor Kozak
- Jacobs Retina Center at Shiley Eye Center, University of California at San Diego, La Jolla, CA 92037, USA
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Kozak I, Cheng L, Mendez T, Davidson MC, Freeman WR. Evaluation of the toxicity of subretinal triamcinolone acetonide in the rabbit. Retina 2006; 26:811-7. [PMID: 16963856 DOI: 10.1097/01.iae.0000244255.22406.2f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Subretinal triamcinolone acetonide (TCA) might be a useful adjuvant in the treatment of subretinal neovascularization. The purpose of this study was to test the toxicity of subretinal TCA in the rabbit eye. METHODS Sixteen New Zealand rabbits were vitrectomized and injected with either decanted TCA solution or vehicle. The concentration of injected TCA was 2 mg, and the delivered volume was 10 microL. Rabbits were examined on days 1, 3, and 7 and then once a week up to 3 months after surgery. Optical coherence tomography was performed at months 1, 2, and 3. After the last examination, which included electroretinography, the rabbits were killed, and the eyes were enucleated for histopathologic analysis. RESULTS Subretinal TCA appeared as a white circumscribed deposit. As the drug disappeared, areas of hyperpigmentation were seen adjacent to the drug deposit. Electroretinography tracings were normal, indicating no widespread toxic effect. Histologic analysis revealed areas of absence and/or hyperpigmentation of the retinal pigment epithelium and damage to photoreceptors and the outer nuclear layer of the retina. CONCLUSION Subretinal injection of TCA crystals can be toxic to the outer retina and retinal pigment epithelium. Whether the potential beneficial effect of such a high-dose steroid in limiting subretinal inflammation, angiogenesis, and proliferation outweighs toxicity can only be determined from a clinical trial.
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Affiliation(s)
- Igor Kozak
- Jacobs Retina Center, University of California at San Diego, Shiley Eye Center, La Jolla, California 92036-0946, USA
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Beeley NRF, Stewart JM, Tano R, Lawin LR, Chappa RA, Qiu G, Anderson AB, de Juan E, Varner SE. Development, implantation,in vivo elution, and retrieval of a biocompatible, sustained release subretinal drug delivery system. J Biomed Mater Res A 2006; 76:690-8. [PMID: 16302225 DOI: 10.1002/jbm.a.30567] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A biocompatible, sustained-release subretinal drug-delivery platform was developed to overcome the therapeutic accessibility limitations of current retinal disease treatments. The prototype implants were fabricated by coating nitinol, poly(methyl methacrylate) or chromic gut core filaments, with a drug-eluting polymer matrix. The polymer coatings are manufactured and coated by SurModics. The coating is a mixture of poly(butyl methacrylate) and poly(ethylene-co-vinyl acetate). The drug is either triamcinolone acetonide or sirolimus. The rods were successfully implanted into the subretinal space of 20/24 rabbits. Four rabbits were lost to early surgery from a dysfunctional infusion line and hemorrhage. No serious complications were observed during the 4-week follow-up period. Slight conjunctival redness was reported in all rabbits by 1-day follow-up, but the redness had subsided by the following week. Intraocular lens touch occurred in six rabbits during the implantations; of these, four had a lensectomy at the time of surgery, and the remaining two developed cataract. Corneal edema developed in three rabbits by 1-week follow-up, but subsided within 2 weeks. Initial observations of the implantation and elution characteristics revealed that the implants are well tolerated by the retinal tissue and that the implant can elute triamcinolone acetonide for a period of at least 4 weeks without eliciting an inflammatory response or complications. There were adverse clinical indications with the sirolimus-loaded implants at the delivered dose. Device retrieval required an uncomplicated surgical procedure, and revealed no associated or adherent tissue. Implant drug content analysis and opacity changes to the polymer matrix coating following retrieval demonstrated the sustained elution of the drug.
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Affiliation(s)
- Nathan R F Beeley
- Doheny Retina Institute, Doheny Eye Institute and Department of Ophthalmology, Keck School of Medicine, University of Southern California, 1450 San Pablo Street, Los Angeles, 90033, USA
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Barbu E, Verestiuc L, Nevell TG, Tsibouklis J. Polymeric materials for ophthalmic drug delivery: trends and perspectives. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b605640g] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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