Structural design of contact lens-based drug delivery systems; in vitro and in vivo studies of ocular triggering mechanisms

Mahomed, Anisa, Wolffsohn, James S. and Tighe, Brian J. (2016). Structural design of contact lens-based drug delivery systems; in vitro and in vivo studies of ocular triggering mechanisms. Contact Lens and Anterior Eye, 39 (2), pp. 97-105.

Abstract

This study identifies and investigates the potential use of in-eye trigger mechanisms to supplement the widely available information on release of ophthalmic drugs from contact lenses under passive release conditions. Ophthalmic dyes and surrogates have been successfully employed to investigate how these factors can be drawn together to make a successful system. The storage of a drug-containing lens in a pH lower than that of the ocular environment can be used to establish an equilibrium that favours retention of the drug in the lens prior to ocular insertion. Although release under passive conditions does not result in complete dye elution, the use of mechanical agitation techniques which mimic the eyelid blink action in conjunction with ocular tear chemistry promotes further release. In this way differentiation between passive and triggered in vitro release characteristics can be established. Investigation of the role of individual tear proteins revealed significant differences in their ability to alter the equilibrium between matrix-held and eluate-held dye or drug. These individual experiments were then investigated in vivo using ophthalmic dyes. Complete elution was found to be achievable in-eye; this demonstrated the importance of that fraction of the drug retained under passive conditions and the triggering effect of in-eye conditions on the release process. Understanding both the structure-property relationship between drug and material and in-eye trigger mechanisms, using ophthalmic dyes as a surrogate, provides the basis of knowledge necessary to design ocular drug delivery vehicles for in-eye release in a controllable manner.

Publication DOI: https://doi.org/10.1016/j.clae.2015.07.007
Divisions: Engineering & Applied Sciences > Chemical Engineering & Applied Chemistry
Life & Health Sciences > Ophthalmic Research Group
Life & Health Sciences > Optometry
Life & Health Sciences
Life & Health Sciences > Vision, Hearing and Language
Engineering & Applied Sciences > Aston Institute of Materials Research (AIMR)
Additional Information: © 2015, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Uncontrolled Keywords: ocular drug delivery,ocular environment,ophthalmic dyes,trigger release mechanism,Ophthalmology,Optometry
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
Published Date: 2016-04
Authors: Mahomed, Anisa ( 0000-0002-3719-7543)
Wolffsohn, James S. ( 0000-0003-4673-8927)
Tighe, Brian J.

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