Positively and negatively charged submicron emulsions for enhanced topicaldelivery of antifungal drugs

Charged submicron emulsions are a priori interesting candidates for the del ivery of drugs in and/or through the skin. In the present study, it was pos sible by using stearylamine or deoxycholic acid (DCA) to incorporate either econazole or miconazole nitrate, respectively, in positively and negativel y charged submicron emulsions. The investigation of the relationship betwee n the physicochemical properties of the vehicles, especially the charge of the emulsion and skin permeation, was conducted ex vivo during percutaneous absorption experiments using hairless female rat skin. In addition, drug q uantification was carried out using two different analytical techniques (HP LC and radioactivity measurements) in order to examine if the drug analysis approach might affect the results. The results clearly indicate that the s urface-modified droplets have a significant influence on the diffusion thro ugh the skin. Furthermore, the method of preparation of the formulation and subsequently the analytical method of drug concentration measurement are a ble to influence the results of percutaneous experiments. (C) 1999 Elsevier Science B.V. All rights reserved.