Evaluation of a polysiloxane-collagen biphasic membrane: a model for in vitro skin permeation studies

This work presents results of the evaluation of a polysiloxane-collagen biphasic membrane (Integra), proposed by us for the first time for in vitro skin permeation studies. This heteropolar biphasic membrane similar to human skin presents both lipophilic and hydrophilic barriers to drug permeation. Eight drugs with various physicochemical characteristics were tested for permeation profiles through the biphasic membrane. The effect of different system compositions and experimental conditions was also studied. A linear correlation was obtained between the permeability coefficients (kp) and logD of molecules possessing different lipophilicities. The drug permeation fluxes through the membrane were concentration dependent. The membrane impeded the permeation of rifampicine, an 800 Da molecule. Moreover, for the examined drugs, a linear relationship between steady state drug fluxes through the membrane and the human skin was found. Donor composition similarly affected the permeation profiles through membrane and human skin. The similarities in permeation behavior of the proposed biphasic membrane as compared to human skin may allow for its use in the future for screening drug candidates, development of generic dermal pharmaceutical products and optimization of topical dosage forms.