Controlled release of cyclosporine from VP-HEMA copolymer systems of adjustable resorption monitorized by MEKC

Soluble, uncrosslinked and high molecular weight copolymers of vinylpyrroli done, VP, with 2-hydroxyethyl methacrylate, HEMA, prepared by free radical copolymerization, are proposed as supports for the modulated release of dru gs, taking cyclosporine as a model system. The copolymerization parameters described as reactivity ratios, r(VP) = 0.08 and r(HEMA) = 7.97, indicate t hat the copolymer systems prepared at high conversion have two main compone nts with a microstructural arrangement which depends on the average composi tion, i.e., an initial HEMA-rich copolymer and a final PVP homopolymer or V P-rich copolymer. This microstructural distribution controls the resorption rate of the polymeric support and therefore the release process of cyclosp orine which is demonstrated experimentally by the application of a modern t echnique known as micellar electrokinetic capillary chromatography (MEKC). (C) 2000 Elsevier Science Ltd. All rights reserved.