A comparison of the incorporation of model steroids into non-ionic micellar and microemulsion systems

The incorporation of testosterone and two of its esters, and progesterone and one of its esters (log Poct varying from 3.3 to 6.9) into 2% w/w soybean oil/Brij 96 microemulsions and Brij 96 surfactant systems has been examined. Possible sites of incorporation have been investigated. The drug carrying improvement of an oil-in-water microemulsion over a micellar system appears to depend on the solubility of the drug in the dispersed oil phase and is significant only for very lipophilic drugs.