Transmembrane penetration enhancer

A method for delivering an active agent through the skin of a patient in need thereof, said method comprising contacting the skin of said patient with a transmembrane penetration enhancer consisting of said active agent, wherein said transmembrane penetration enhancer is a thermotropic liquid crystal transmembrane penetration enhancer consisting of:

• 1) one or a fused mixture of two or more cholesteryl esters in an amount of 90% or more;
• and
• 2) an active agent selected from the group consisting of diazepam, oxazepam, lorazepam, clonazepam, bromazepam, alprazolam, clotiazepam, clobazam, buspirone, amphetamine, methamphetamine, methylphenidate, cathine, fenfluramine, piracetam, and meclofenoxate, in an amount of 10% or less;
• wherein said thermotropic liquid crystal transmembrane penetration enhancer delivers said active agent through the skin of the patient when said cholesteryl esters are in a mesomorphic state.