Composite poly(2-hydroxyethyl methacrylate) membranes as rate-controlling barriers for transdermal applications.

Composite membranes were prepared by casting a linear poly(2-hydroxyethyl 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 swelling and permeation properties of these membranes were evaluated, with a system of nitroglycerin and aqueous ethanol solution, for potential application in transdermal drug delivery. The degree of swelling of these membranes in water and aqueous ethanol decreases as the cross-linker content is increased and increases slightly with an increase in the original molecular weight of the linear pHEMA. The permeation rates of both nitroglycerin and ethanol increase as the cross-linker content is reduced, the polymer molecular weight increases, and the concentration of the casting solution or membrane thickness decreases. Depending on the preparation conditions, the membranes can be tailored to give a permeation flux ranging from 4 to 68 micrograms cm-2 h-1 for nitroglycerin.