Microemulsions as Topical Drug Delivery Vehicles. I. Characterization of a Model System

Abstract

The microemulsion region formed by the water/octanol/dioctyl sodium sulfosuccinate (DSS) was characterized by determination of the phase boundaries, water self diffusion coefficients, and in vitro transdermal permeation for radiolabeled water. The 58:42 ratio of DSS:octanol can incorporate greater than 70% water. It is found that the average self diffusion values for water increase ten-fold as the water content increases from 15 to 58% by weight. Values for normalized in vitro transdermal flux of water from the microemulsion showed a similar trend increasing five-fold over the same water content range. This study shows that delivery of the polar water portion of this microemulsion system is highly dependent upon the composition of the microemulsion.