COMPOSITE POLY(2-HYDROXYETHYL METHACRYLATE) MEMBRANES AS RATE-CONTROLLING BARRIERS FOR TRANSDERMAL APPLICATIONS

Composite membranes were prepared by casting a linear poly(2-hydroxyet hyl methacrylate) (pHEMA) solution onto polyester non-woven supports, and then the supported pHEMA within the membranes was cross-linked by a diisocyanate cross-linking agent to form a network structure. The sw elling and permeation properties of these membranes were evaluated, wi th a system of nitroglycerin and aqueous ethanol solution, for potenti al application in transdermal drug delivery. The degree of swelling of these membranes in water and aqueous ethanol decreases as the cross-l inker content is increased and increases slightly with an increase in the original molecular weight of the linear pHEMA. The permeation rate s of both nitroglycerin and ethanol increase as the cross-linker conte nt is reduced, the polymer molecular weight increases, and the concent ration of the casting solution or membrane thickness decreases. Depend ing on the preparation conditions, the membranes can be tailored to gi ve a permeation flux ranging from 4 to 68 mu g cm(-2) h(-1) for nitrog lycerin. (C) 1997 Elsevier Science Limited.