The influence of liquid crystal system of cholesterol esters on non polar compound permeation in skin was investigated to further understand esters-enhanced permeation mechanism. Investigation studied the effect of liquid crystal system of cholesterol esters on the in vitro permeation of phenazepam from transdermal delivery system across skin. Changes in the amount and conformation of stratum corneum lipids were determined by Fourier transform infrared spectroscopy. Our findings demonstrate that liquid crystal systems of cholesterol esters can be effective enhancer transdermal delivery.