Invert and double emulsions as a base for microheterogeneous matrices for transdermal delivery of lipophilic drugs

Abstract

Stable invert emulsions water/oil and double emulsions oil1/water/oil2 containing polyisobuthylene as pressure-sensitive polymeric adhesive are prepared. The dispersed phase of the invert emulsions contained micelles of the surfactant Tween 80 (Tw) with solubilized drug (Felodipine) and a skin permeation enhancer (glycerol monooleate, GMO). The active components (Felodipine and GMO) of the double emulsions were incorporated into the internal dispersed phase, while the intermediate water layer contained Tw and hydroxypropylcellulose. Ultradispersed polymer films with good adhesion to skin were prepared from both types of emulsions. The films based on double emulsions demonstrate the ability to release Felodipine at therapeutically effective levels and maintain these levels during the first 24 h to attain a therapeutically required dose. The invert and double emulsions were for the first time utilized as bases for microheterogeneous matrices for delivery of a lipophilic drug in bioavailable form.