Effect of Various Physical/Chemical Properties on the Transdermal Delivery of Cyclosporin Through Topical Application

Abstract

The pulpose of this study was to evaluate the effect of (A) skin stripping (B) trans-dermal enhancer and (C) iontophoresis, on the in vitro transdermal delivery of cyclosporin. An in vitro transdermal study through hairless mouse skin using a selected cyclosporin topical formulation was also conducted. Results show that the permeation coeflcient of cyclosporin was increased as the skins were stripped more times. Among the transdermal enhancers, azone, salicyclic acid, dimethyl sulfoxide, sodium lauryl sulfate and Tween 20; azone, and dimethyl sulfoxide were found to significantly increase the cyclosporin delivery; while salicylic acid, sodium lauryl sulfate and Tween 20 had no apparent effects. In further studies to define the optimum concentration of the above enhancers, the greatest effect was determined to be 1% for azone and 5% for dimethyl sulf oxide. Constant voltage iontophoresis was proven to be effective in enhancing the cyclosporin transdermal delivery. Data show that an increase in the permeability was observed when the voltage was increased from 1 to 7 V. The results of in vivo topical application of a selected cyclosporin formulation to hairless muse skin indicate that both blood and skin concentration reached maximum at about 36 hr after application, and that the cyclosporin concentration in the skin was constantly higher (10 times at the peak maximum) than its corresponding blood concentration at the same time intervals