Abstract
New liquid crystal-immobilized membrane (LC-membrane) was prepared to develop the thermo-responsive drug delivery systems, This LC-membrane has high compatibility to a variety of drugs because of its electrical neutrality and the LC can sharply control the membrane permeation of drugs in response to temperature. The application of thermo-responsive LC-membrane to transdermal delivery of glyceryl trinitrate (GTN) and isosorbide dinitrate (ISDN) was studied to achieve the on-off switching release of the vasodilators which reguire “wash-out” from the body to avoid drug tolerance. The permeability of GTN and ISDN through LC-membrane increased above the gel-liquid crystal phase trandition temperature (Tc) of LC(38°C), The LC-membrane suppressed GTN and ISDN permeation through the excised abdominal skin of hairless rat at 32°C to about one-half of that at 38°C Similar tendency was found in the plasma level of GTN and ISDN in hairless rat. It was suggested from these results that the LC-membrane might enable Transdermal Therapeutic Systems to achieve the on-off switching release.
