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Diffusion through the ex vivo vitreal body - Bovine, porcine, and ovine models are poor surrogates for the human vitreous

Shafaie, S; Hutter, V; Brown, MB; Cook, MT; Chau, DYS; (2018) Diffusion through the ex vivo vitreal body - Bovine, porcine, and ovine models are poor surrogates for the human vitreous. International Journal of Pharmaceutics , 550 (1-2) pp. 207-215. 10.1016/j.ijpharm.2018.07.070. Green open access

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Abstract

The human vitreous humour is a complex gel structure whose composition and physical properties can vary considerably from person to person and also change with age. To date, the viscoelastic properties of the human vitreous gel has not been thoroughly investigated and despite many years of intensive research, an ideal vitreous substitute remains a challenge. Understanding the physical structure and properties of the vitreous is of fundamental and therapeutic interest, providing a clear insight into diffusion and transport of administered ophthalmic drug molecules into the vitreous. A number of mammalian surrogates, mainly bovine, porcine and ovine vitreous humours have been used in the literature as a means of studying ophthalmic drug transport and diffusion. In this study, the mechanical, physical and rheological properties of ovine, porcine, and bovine surrogates were investigated and compared to human vitreous. In addition, a bespoke Franz cell construct was used to compare the diffusion of a model drug (fluorescein) through vitreous samples. Despite the similarity in rheological properties between bovine, porcine and human vitreous samples, diffusion of fluorescein through the different vitreous samples revealed great differences in values of steady-state flux and diffusion coefficient. In addition, a first-generation vitreous mimic, composed of 4.5 mg/mL hyaluronic acid with complex viscosity of 0.3 ± 0.01 Pa has been evaluated and was demonstrated to be a better mimic of the human vitreous than the mammalian samples investigated.

Type: Article
Title: Diffusion through the ex vivo vitreal body - Bovine, porcine, and ovine models are poor surrogates for the human vitreous
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.ijpharm.2018.07.070
Publisher version: https://doi.org/10.1016/j.ijpharm.2018.07.070
Language: English
Additional information: Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/BY/4.0/).
Keywords: Franz cell, Hyaluronic acid, Hydrogel, Ocular drug delivery, Permeability, Diffusion, Rheology, Vitreous substitute
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Eastman Dental Institute
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Eastman Dental Institute > Biomaterials and Tissue Eng
URI: https://discovery.ucl.ac.uk/id/eprint/10069780
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