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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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2
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Velentza-Almpani A, Ibeanu N, Liu T, Redhead C, Tee Khaw P, Brocchini S, Awwad S, Bouremel Y. Effects of Flow Hydrodynamics and Eye Movements on Intraocular Drug Clearance. Pharmaceutics 2022; 14:pharmaceutics14061267. [PMID: 35745839 PMCID: PMC9229170 DOI: 10.3390/pharmaceutics14061267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/09/2022] [Accepted: 06/12/2022] [Indexed: 02/06/2023] Open
Abstract
New in vitro prototypes (PK-Eye™) were tested with and without eye movement to understand diffusion and convection effects on intraocular clearance. Port placement in front ((i) ciliary inflow model) and behind the model lens ((ii) posterior inflow model) was used to study bevacizumab (1.25 mg/50 µL) and dexamethasone (0.1 mg/100 µL) in phosphate-buffered saline (PBS, pH 7.4) and simulated vitreal fluid (SVF). Dexamethasone was studied in a (iii) retinal-choroid-sclera (RCS) outflow model (with ciliary inflow and two outflow pathways). Ciliary vs. posterior inflow placement did not affect the half-life for dexamethasone at 2.0 µL/min using PBS (4.7 days vs. 4.8 days) and SVF (4.9 days with ciliary inflow), but it did decrease the half-life for bevacizumab in PBS (20.4 days vs. 2.4 days) and SVF (19.2 days vs. 10.8 days). Eye movement only affected the half-life of dexamethasone in both media. Dexamethasone in the RCS model showed approximately 20% and 75% clearance from the RCS and anterior outflows, respectively. The half-life of the protein was comparable to human data in the posterior inflow model. Shorter half-life values for a protein in a ciliary inflow model can be achieved with other eye movements. The RCS flow model with eye movement was comparable to human half-life data for dexamethasone.
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Affiliation(s)
- Angeliki Velentza-Almpani
- Optceutics Ltd., 28a Menelik Road, London NW2 3RP, UK; (A.V.-A.); (N.I.); (T.L.); (C.R.); (P.T.K.); (S.B.)
- Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
| | - Nkiruka Ibeanu
- Optceutics Ltd., 28a Menelik Road, London NW2 3RP, UK; (A.V.-A.); (N.I.); (T.L.); (C.R.); (P.T.K.); (S.B.)
- Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Tianyang Liu
- Optceutics Ltd., 28a Menelik Road, London NW2 3RP, UK; (A.V.-A.); (N.I.); (T.L.); (C.R.); (P.T.K.); (S.B.)
- Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
| | - Christopher Redhead
- Optceutics Ltd., 28a Menelik Road, London NW2 3RP, UK; (A.V.-A.); (N.I.); (T.L.); (C.R.); (P.T.K.); (S.B.)
| | - Peng Tee Khaw
- Optceutics Ltd., 28a Menelik Road, London NW2 3RP, UK; (A.V.-A.); (N.I.); (T.L.); (C.R.); (P.T.K.); (S.B.)
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Steve Brocchini
- Optceutics Ltd., 28a Menelik Road, London NW2 3RP, UK; (A.V.-A.); (N.I.); (T.L.); (C.R.); (P.T.K.); (S.B.)
- Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Sahar Awwad
- Optceutics Ltd., 28a Menelik Road, London NW2 3RP, UK; (A.V.-A.); (N.I.); (T.L.); (C.R.); (P.T.K.); (S.B.)
- Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Correspondence: (S.A.); (Y.B.); Tel.: +44-207-753-5802 (S.A.)
| | - Yann Bouremel
- Optceutics Ltd., 28a Menelik Road, London NW2 3RP, UK; (A.V.-A.); (N.I.); (T.L.); (C.R.); (P.T.K.); (S.B.)
- Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Correspondence: (S.A.); (Y.B.); Tel.: +44-207-753-5802 (S.A.)
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3
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Wang R, Tsai JH, Snead MP, Alexander P, Wilson DI. Stability of the Interface Between Two Immiscible Liquids in a Model Eye Subject to Saccadic Motion. J Biomech Eng 2022; 144:1127985. [PMID: 34773461 DOI: 10.1115/1.4053004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Indexed: 11/08/2022]
Abstract
The interface between silicone oil and saline layers in a three-dimensional model of the eye chamber was studied under different eye-like saccadic motions in order to determine the stability of the interface and propensity for emulsification in the bulk. The effect of level of fill, saccade amplitude, angular velocity, latency time, and orientation were investigated experimentally in spherical flasks with internal diameters 10, 28, and 40 mm, as well as a 28 mm diameter flask with an indent replicating the lens or the presence of a buckle. The deformation of the interface was quantified in terms of the change in its length in two-dimensional images. The deformation increased with Weber number, We, and was roughly proportional to We for We > 1. The presence of the lens gave rise to higher deformation near this feature. In all cases emulsification was not observed in either bulk fluid. The velocity profile in the spherical configuration was mapped using particle imaging velocimetry and is compared with an analytical solution and a short computational fluid dynamics simulation study. These confirm that the saccadic motion induces flow near the wall in the saline layer and significantly further into the chamber in the silicone oil. Surfactants soluble in the aqueous and oil phases reduced the interfacial tension, increasing deformation but did not lead to emulsification in the bulk.
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Affiliation(s)
- Ru Wang
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, UK
| | - Jheng-Han Tsai
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, UK
| | - Martin P Snead
- Department of Ophthalmology, University of Cambridge, Addenbrookes Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - Philip Alexander
- Department of Ophthalmology, University of Cambridge, Addenbrookes Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - D Ian Wilson
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, UK
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4
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Dalvin LA. Thiolated Chitosan-carboxymethyl Dextran Nanoparticles: Improving Intravitreal Drug Bioavailability for Retinoblastoma. J Ophthalmic Vis Res 2022; 17:1-3. [PMID: 35194489 PMCID: PMC8850858 DOI: 10.18502/jovr.v17i1.10163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 11/12/2021] [Indexed: 11/24/2022] Open
Affiliation(s)
- Lauren A Dalvin
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA
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5
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Ocular Fluid Mechanics and Drug Delivery: A Review of Mathematical and Computational Models. Pharm Res 2021; 38:2003-2033. [PMID: 34936067 DOI: 10.1007/s11095-021-03141-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/10/2021] [Indexed: 10/19/2022]
Abstract
The human eye is a complex biomechanical structure with a range of biomechanical processes involved in various physiological as well as pathological conditions. Fluid flow inside different domains of the eye is one of the most significant biomechanical processes that tend to perform a wide variety of functions and when combined with other biophysical processes play a crucial role in ocular drug delivery. However, it is quite difficult to comprehend the effect of these processes on drug transport and associated treatment experimentally because of ethical constraints and economic feasibility. Computational modeling on the other hand is an excellent means to understand the associated complexity between these aforementioned processes and drug delivery. A wide range of computational models specific to different types of fluids present in different domains of the eye as well as varying drug delivery modes has been established to understand the fluid flow behavior and drug transport phenomenon in an insilico manner. These computational models have been used as a non-invasive tool to aid ophthalmologists in identifying the challenges associated with a particular drug delivery mode while treating particular eye diseases and to advance the understanding of the biomechanical behavior of the eye. In this regard, the author attempts to summarize the existing computational and mathematical approaches proposed in the last two decades for understanding the fluid mechanics and drug transport associated with different domains of the eye, together with their application to modify the existing treatment processes.
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Ferroni M, De Gaetano F, Cereda MG, Boschetti F. Evaluation of the ocular fluid dynamic effects on intraocular magnesium-based device: A comparison between CFD and FSI approaches. Med Eng Phys 2020; 86:20-28. [PMID: 33261729 DOI: 10.1016/j.medengphy.2020.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 09/04/2020] [Accepted: 10/05/2020] [Indexed: 11/28/2022]
Abstract
Magnesium is an essential element for the ocular functions and used for the realization of medical devices due to its low corrosion resistance, bioresorbable nature and biocompatibility. Wet age-related macular degeneration is one of the main causes of blindness with patients treated by intravitreal injections of inhibitor drugs. According to the need to reduce the number of injections, the development of new drug delivery devices able to extend the therapeutical outcomes is mandatory and magnesium can be considered as a promising candidate. The aim of the work concerns the evaluation of the ocular fluid dynamic role on a magnesium-based device placed in the vitreous chamber. Particularly, the fluid-induced shear stress field on the surfaces in contact with the liquefied vitreous was studied. Both computational fluid dynamic and fluid-structure interaction approaches were proposed and then compared. Saccadic motion was implemented to recreate the vitreous fluid dynamics. High changes in terms of fluid-induced shear stress field varying the CFD and FSI numerical approaches and kinematic parameters of the saccadic function can be noticed. The comparison between CFD and FSI approaches showed minor significant differences and both implementations suggested the possibility to obtain a uniform and controlled corrosion of the device.
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Affiliation(s)
- Marco Ferroni
- LaBS, Chemistry Materials and Chemical Engineering Department "Giulio Natta", Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy; MgShell S.r.l., Milan, Italy.
| | - Francesco De Gaetano
- LaBS, Chemistry Materials and Chemical Engineering Department "Giulio Natta", Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy; MgShell S.r.l., Milan, Italy
| | - Matteo Giuseppe Cereda
- Eye Clinic, Department of Biomedical and clinical science "Luigi Sacco", Sacco Hospital, University of Milan, Via G.B. Grassi 74, 20157 Milan, Italy
| | - Federica Boschetti
- LaBS, Chemistry Materials and Chemical Engineering Department "Giulio Natta", Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy
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7
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Tram NK, Maxwell CJ, Swindle-Reilly KE. Macro- and Microscale Properties of the Vitreous Humor to Inform Substitute Design and Intravitreal Biotransport. Curr Eye Res 2020; 46:429-444. [PMID: 33040616 DOI: 10.1080/02713683.2020.1826977] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Research on the vitreous humor and development of hydrogel vitreous substitutes have gained a rapid increase in interest within the past two decades. However, the properties of the vitreous humor and vitreous substitutes have yet to be consolidated. In this paper, the mechanical properties of the vitreous humor and hydrogel vitreous substitutes were systematically reviewed. The number of publications on the vitreous humor and vitreous substitutes over the years, as well as their respective testing conditions and testing techniques were analyzed. The mechanical properties of the human vitreous were found to be most similar to the vitreous of pigs and rabbits. The storage and loss moduli of the hydrogel vitreous substitutes developed were found to be orders of magnitude higher in comparison to the native human vitreous. However, the reported modulus for human vitreous, which was most commonly tested in vitro, has been hypothesized to be different in vivo. Future studies should focus on testing the mechanical properties of the vitreous in situ or in vivo. In addition to its mechanical properties, the vitreous humor has other biotransport mechanisms and biochemical functions that establish a redox balance and maintain an oxygen gradient inside the vitreous chamber to protect intraocular tissues from oxidative damage. Biomimetic hydrogel vitreous substitutes have the potential to provide ophthalmologists with additional avenues for treating and controlling vitreoretinal diseases while preventing complications after vitrectomy. Due to the proximity and interconnectedness of the vitreous humor to other ocular tissues, particularly the lens and the retina, more interest has been placed on understanding the properties of the vitreous humor in recent years. A better understanding of the properties of the vitreous humor will aid in improving the design of biomimetic vitreous substitutes and enhancing intravitreal biotransport.
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Affiliation(s)
- Nguyen K Tram
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Courtney J Maxwell
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Katelyn E Swindle-Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.,William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA.,Department of Ophthalmology & Visual Science, The Ohio State University, Columbus, OH, USA
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Bayat J, Emdad H, Abouali O. 3D numerical investigation of the fluid mechanics in a partially liquefied vitreous humor due to saccadic eye movement. Comput Biol Med 2020; 125:103955. [DOI: 10.1016/j.compbiomed.2020.103955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 07/31/2020] [Accepted: 07/31/2020] [Indexed: 10/23/2022]
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9
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Preclinical challenges for developing long acting intravitreal medicines. Eur J Pharm Biopharm 2020; 153:130-149. [DOI: 10.1016/j.ejpb.2020.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 05/01/2020] [Accepted: 05/08/2020] [Indexed: 02/07/2023]
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10
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A drug delivery analysis of large molecules in ocular vitreous chamber: Dependency on saccadic movements after intravitreal injection. Med Eng Phys 2020; 82:49-57. [PMID: 32709265 DOI: 10.1016/j.medengphy.2020.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 05/14/2020] [Accepted: 06/15/2020] [Indexed: 02/06/2023]
Abstract
The purpose of this study is to investigate the effect of vitreous sloshing induced by saccades on the intravitreal delivery of large molecule drugs. The vitreous body was considered in its age-related liquefaction condition. Fluid dynamics and large molecule distribution were described by the coupling of mass conservation's and Fick's laws with continuity and momentum equations for a Newtonian incompressible fluid in a 3D unsteady analysis. Two injection sites were analyzed, in both the mixing effect of a 50° periodic saccade leads to uniform drug distribution in 30 s of simulation, the initial bolus site being left after 3 s of simulation. In absence of saccadic movements, the dominant transport contribution is the diffusive one and large molecules hardly reach their uniform distribution inside the vitreous cavity. A model describing the intravitreal distribution of large molecules in presence of saccades was developed, improving the understanding of drug transport mechanism after an intravitreal injection and highlighting how advection contribution enhances its distribution in the vitreous chamber.
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Thakur SS, Shenoy SK, Suk JS, Hanes JS, Rupenthal ID. Validation of hyaluronic acid-agar-based hydrogels as vitreous humor mimetics for in vitro drug and particle migration evaluations. Eur J Pharm Biopharm 2020; 148:118-125. [PMID: 31981693 DOI: 10.1016/j.ejpb.2020.01.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/16/2020] [Accepted: 01/19/2020] [Indexed: 12/26/2022]
Abstract
Artificial vitreous humor holds immense potential for use in in vitro intravitreal drug delivery assays. In this study, we investigated rheological properties and drug or nanoparticle migration in hyaluronic acid (HA) - agar based hydrogels and compared these characteristics with bovine vitreous humor. Gel compositions identified in literature containing HA (0.7-5.0 mg/ml) and agar (0.95-4.0 mg/ml) were classified as either high (VH), medium (VM) or low (VL) polymer load. Viscoelastic behavior was evaluated using oscillatory rheology, and migration of differently sized and charged polystyrene nanoparticles (NPs) through the different gels was determined via multiple particle tracking. Comparable rheological behaviour was observed between VL and bovine vitreous. Tracking evaluations revealed that increasing particle size and gel viscosity slowed NP migration. Additionally, 100 nm anionic NPs migrated slower than neutral NPs in VL and VM, while cationic NPs were immobile in all gels. Finally, distribution and clearance of sodium fluorescein was used to model drug mobility through the gels using a custom-built eye model. Flow and angular movement only influenced drug migration in VL and VM, but not VH. Finally, VL and VM demonstrated to have the most similar sodium fluorescein clearance to that of bovine vitreous humor. Together, these evaluations demonstrate that low viscosity HA-agar gels can be used to approximate nanoparticle and drug migration through biological vitreous humor.
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Affiliation(s)
- Sachin S Thakur
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Siddharth K Shenoy
- Center for Nanomedicine, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA
| | - Jung Soo Suk
- Center for Nanomedicine, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA
| | - Justin S Hanes
- Center for Nanomedicine, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Pharmacology & Molecular Sciences, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA
| | - Ilva D Rupenthal
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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Thakur SS, Chen YS, Houston ZH, Fletcher N, Barnett NL, Thurecht KJ, Rupenthal ID, Parekh HS. Ultrasound-responsive nanobubbles for enhanced intravitreal drug migration: An ex vivo evaluation. Eur J Pharm Biopharm 2019; 136:102-107. [DOI: 10.1016/j.ejpb.2019.01.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/14/2019] [Accepted: 01/15/2019] [Indexed: 02/08/2023]
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13
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Yu MD, Dalvin LA, Welch RJ, Shields CL. Precision Intravitreal Chemotherapy for Localized Vitreous Seeding of Retinoblastoma. Ocul Oncol Pathol 2018; 5:284-289. [PMID: 31367592 DOI: 10.1159/000491432] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/20/2018] [Indexed: 11/19/2022] Open
Abstract
Purpose To describe and evaluate the effectivity of a novel precision intravitreal injection technique for select cases of localized vitreous seeding in retinoblastoma. Methods Patients with localized vitreous seeds from retinoblastoma received intravitreal chemotherapy via a precision injection technique (P-IVitC) intended to optimize local delivery of melphalan to target seeds. The needle was inserted trans-pars plana and chemotherapy deposited within 3 mm of the target seed(s) under indirect ophthalmoscopic guidance. Without subsequent globe manipulation, the head was then positioned to promote gravity-dependent settling of chemotherapy. Results There were 8 eyes of 8 patients treated with P-IVitC for active vitreous seeds following adequate solid tumor control with intravenous chemotherapy (n = 3, 38%) or intra-arterial chemotherapy (n = 5, 63%). Viable vitreous seeds were primarily solitary spheres (n = 6, 75%) and measured an average of 2.7 mm in diameter. Vitreous seed resolution (n = 8, 100%) was noted after a mean of 2.6 injections (median 2; range 1-3) of 20 μg melphalan. There was no recurrence at a mean follow-up of 10.0 months. Only 1 eye had an associated complication (focal retinal pigment epithelial mottling, n = 1, 13%). Conclusions With direct delivery of chemotherapy to within 3-4 mm of vitreous seed activity, P-IVitC provided complete control of localized vitreous seeds with minimal toxicity.
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Affiliation(s)
- Michael D Yu
- Ocular Oncology Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Lauren A Dalvin
- Ocular Oncology Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA
| | - R Joel Welch
- Ocular Oncology Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Carol L Shields
- Ocular Oncology Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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14
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A Combined Approach for the Analysis of Ocular Fluid Dynamics in the Presence of Saccadic Movements. Ann Biomed Eng 2018; 46:2091-2101. [DOI: 10.1007/s10439-018-02110-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/27/2018] [Indexed: 01/04/2023]
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15
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Peynshaert K, Devoldere J, De Smedt SC, Remaut K. In vitro and ex vivo models to study drug delivery barriers in the posterior segment of the eye. Adv Drug Deliv Rev 2018; 126:44-57. [PMID: 28939376 DOI: 10.1016/j.addr.2017.09.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 07/18/2017] [Accepted: 09/08/2017] [Indexed: 12/18/2022]
Abstract
Many ocular disorders leading to blindness could benefit from efficient delivery of therapeutics to the retina. However, despite extensive research into drug delivery vehicles and administration techniques, efficacy remains limited because of the many static and dynamic barriers present in the eye. Comprehension of the various barriers and especially how to overcome them can improve our ability to estimate the potential of existent drug delivery vectors and support the design of new ones. To this end, this review gives an overview of the most important ocular barriers for each administration route to the back of the eye. For each barrier, its biological composition and its role as an obstacle towards macromolecules, nanoparticles and viral vectors will be discussed; special attention will be paid to the influence of size, charge and lipophilicity of drug(s) (carrier) on their ability to overcome each barrier. Finally, the most significant available in vitro and ex vivo methods and models to test the potential of a therapeutic to cross each barrier are listed.
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16
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Boushehrian HH, Abouali O, Jafarpur K, Ghaffarieh A, Ahmadi G. Relationship between saccadic eye movements and formation of the Krukenberg's spindle-a CFD study. MATHEMATICAL MEDICINE AND BIOLOGY-A JOURNAL OF THE IMA 2017; 34:293-312. [PMID: 27118396 DOI: 10.1093/imammb/dqw007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 02/21/2016] [Indexed: 11/13/2022]
Abstract
In this research, a series of numerical simulations for evaluating the effects of saccadic eye movement on the aqueous humour (AH) flow field and movement of pigment particles in the anterior chamber (AC) was performed. To predict the flow field of AH in the AC, the unsteady forms of continuity, momentum balance and conservation of energy equations were solved using the dynamic mesh technique for simulating the saccadic motions. Different orientations of the human eye including horizontal, vertical and angles of 10° and 20° were considered. The Lagrangian particle trajectory analysis approach was used to find the trajectories of pigment particles in the eye. Particular attention was given to the relation between the saccadic eye movement and potential formation of Krukenberg's spindle in the eye. The simulation results revealed that the natural convection flow was an effective mechanism for transferring pigment particles from the iris to near the cornea. In addition, the saccadic eye movement was the dominant mechanism for deposition of pigment particles on the cornea, which could lead to the formation of Krukenberg's spindle. The effect of amplitude of saccade motion angle in addition to the orientation of the eye on the formation of Krukenberg's spindle was investigated.
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Affiliation(s)
| | - Omid Abouali
- School of Mechanical Engineering, Shiraz University, Shiraz, Iran
| | - Khosrow Jafarpur
- School of Mechanical Engineering, Shiraz University, Shiraz, Iran
| | - Alireza Ghaffarieh
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USAand
| | - Goodarz Ahmadi
- Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY 13699-5725, USA
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Bayatpour D, Abouali O, Ghaffarieh A, Ahmadi G. In silico investigation of cornea deformation during irrigation/aspiration in phacoemulsification in cataract surgery. Med Eng Phys 2017; 43:77-85. [PMID: 28291699 DOI: 10.1016/j.medengphy.2017.02.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 01/25/2017] [Accepted: 02/12/2017] [Indexed: 10/20/2022]
Abstract
To analyze the stress, strain and displacement of the human cornea under the action of negative intraocular pressure, which occurs during phacoemulsification in cataract surgery, a multidisciplinary approach including biomedical engineering, solid mechanics, numerical analysis, and fluid dynamics was used. Fluid-structure interaction method was implemented using 3-dimensional nonlinear finite element analysis of cornea tissue in conjunction with CFD analysis of anterior chamber fluid flow to study the deformation of the cornea under negative gage pressure during irrigation and aspiration (I/A). The computational model of the eye includes both cornea and sclera. To increase the accuracy of the computational model, both cornea hyperelasticity and thickness variation were included in the analysis. The simulation was performed for both coaxial and bimanual I/A systems with different flow rates. The cornea deformations for various flow rates were evaluated, and the possibility of an unstable anterior chamber was assessed. The results show that the critical pressure in the anterior chamber, which may lead to the surge condition due to buckling of the cornea, is sub-ambient (below zero gauge pressure). Anterior chamber instability occurs at higher volume flow rates for coaxial I/A system compared with that for bimanual system, but the deformation of the cornea is more intense for the bimanual system.
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Affiliation(s)
| | - Omid Abouali
- School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
| | - Alireza Ghaffarieh
- Department of Pathology and Laboratory Medicine, IndianaUniversitySchool of Medicine, Indianapolis, IN, USA
| | - Goodarz Ahmadi
- Aeronautical and Mechanical Engineering Department, Clarkson University, Potsdam, NY, USA
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Modarreszadeh S, Abouali O, Ghaffarieh A, Ahmadi G. Physiology of aqueous humor dynamic in the anterior chamber due to rapid eye movement. Physiol Behav 2014; 135:112-8. [PMID: 24866913 DOI: 10.1016/j.physbeh.2014.05.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Revised: 04/28/2014] [Accepted: 05/16/2014] [Indexed: 11/30/2022]
Abstract
The nature of aqueous humor (AH) mixing in the anterior chamber (AC) of the human eye due to rapid eye movement (REM) has not been fully understood and has been somewhat a controversial issue. This study uses a computational modeling approach to shed light on this issue. For this purpose a numerical method was developed and used to solve the mathematical equations governing the flow and mixing of aqueous humor motion in the eye subjected to such movements. Based on the experimental measurements available in the literature for the average and maximum amplitudes of the eye movements, a harmonic model for the REM was developed. The corresponding instantaneous and time-averaged velocity fields were evaluated. The simulation results showed that, contrary to earlier reports, the REM led to complex flow structures and a 3-D mixing of AH in the anterior chamber. In addition, the mixing velocity increased in direct proportion to the REM amplitudes. Thus, the AC flow generated by REM could carry nutrients to the posterior surface of the cornea during the sleep. Furthermore, the shear stress acting on the corneal endothelial cells due to REM was computed and compared with that of buoyancy driven flow in the AC due to temperature gradient. It was found that the shear stress generated by REM is much higher than that introduced by the natural convection. A video file for providing a better understanding of the AH mixing process in the AC was also prepared. This video is available on the web.
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Affiliation(s)
| | - Omid Abouali
- School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
| | - Alireza Ghaffarieh
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI, USA
| | - Goodarz Ahmadi
- Department of Aeronautical and Mechanical Engineering, Clarkson University, Potsdam, NY, USA
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