A microemulsion containing (A) a highly polar and fat-soluble oil drug, a highly polar oil and a lowly polar oil, (B) a polyglycerol mono-fatty acid ester and (C) a water-soluble polyhydric alcohol, wherein the amount of (B) is 0.3 to 3 parts by weight based on one part by weight of (A) and the amount of (C) is 0.1 to 3 parts by weight based on one part by weight of the total amount of (A) and (B). The present invention makes it possible to make a microemulsion containing a highly polar and fat-soluble drug which is highly stable.

Un microemulsion que contiene (a) una droga altamente polar y soluble en la grasa del aceite, un aceite altamente polar y un aceite polar humilde, (b) un éster ácido mono-graso del polyglycerol y (c) un alcohol polyhydric soluble en agua, en donde la cantidad de (b) es 0.3 a 3 porciones por el peso basado en una porción en peso de (a) y la cantidad de (c) es 0.1 a 3 porciones al lado del peso basado en una porción en peso de la cantidad total de (a) y de (b). La actual invención permite hacer un microemulsion que contiene una droga altamente polar y soluble en la grasa que sea altamente estable.