Abstract
Four polymeric membranes were prepared consisting of various ratios of 2-hydroxyethyl-methacrylate/polydimethylsiloxane-methacrylate copolymer. These membranes had both lipophilic and hydrophilic domains in their copolymer networks like skin barrier. From permeation studies of the aqueous solutions or suspensions of various lipophilic and hydrophilic drugs using these membranes, a membrane having a similar drug permeability to hairless rat and human skins was selected. Permeation of indomethacin through the selected polymer membrane from simple ointment, gel and a marketed cream were then measured. About 102 times higher permeability was found in the polymer membrane than through excised hairless rat skin, but the rank order of the permeability through the polymer membrane among the formulations was the same through the skin membranes. These higher permeations of indomethacin were probably related to physical and chemical properties of pharmaceutical additives in the topical formulations. It is concluded that these synthetic polymer membranes may be utilized as an alternative tool to predict human or rat skin permeability of various (hydrophilic or lipophilic) drugs as well as to screen drug candidates for transdermal drug delivery.
