Design and evaluation of chitosan-HPMC polymeric films for transdermal delivery of captopril

Drug permeation through the skin layers remains a major challenge in transdermal drug delivery. In this study, the permeation enhancing property of chitosan together with its rate-controlling property has been utilized in the development of an efficient transdermal delivery system, using captopril as a model drug. Chitosan-hydroxypropyl methylcellulose (HPMC)films were developed by solvent evaporation technique. The films were characterized for appearance, thickness, weight uniformity, drug content, folding endurance and moisture absorption. Drug-polymer interaction was assessed using ATR-FTIR spectroscopy and Differential Scanning Calorimetry. The invitro permeation,carried out in Franz-type diffusion cells using synthetic Strat-M^® membrane, demonstrated that the film coded F2 (Chitosan:HPMC = 50:50) showeda more significant increase in drug permeation than F1(Chitosan:HPMC = 90:10) with a flux value 86.7 µg/cm²/h. The physicochemical characterization and the stability studies confirmed that the formulated films were chemically and physically stable.