TRANSDERMAL ABSORPTION PREPARATION

摘要

The present invention provides a transdermal absorption preparation whereby a drug, which takes effect with a small amount, and is liable to be decomposed, solid at ordinary temperatures, water-soluble and less absorbable into the skin, can be stored stably for a long period of time and, can be transdermally administered at a high releasing ratio and yet releasing slowly, when applied to the skin. The constitution of the present invention is as follows: a transdermal absorption preparation which comprises a drug-storing layer containing a drug and having a drug- releasing face coated with a drug-releasing controlling membrane, wherein said drug-storing layer comprises as a base a heat-sensitive segmented polyurethane represented by the general formula: R - A - (U) - F - (U) - B - R' wherein A and B each represents a polymer of ethylene oxide, propylene oxide, tetramethylene oxide or 1,2-butylene oxide, or a random or block copolymer thereof, R and R' each represents a terminal H, CH3, C2H5, C3H7 or C4H9, A=B or A.noteq.FB, R=R' or R.noteq.R', F represents a constituting structure which is a moiety of a diisocyanate compound excluding two isocyanate groups, and (U) represents a urethane bond, and at least one of A and B is hydrophilic and at the same time at least one -62- of A and B has a characteristic that it melts near the temperature of human skin, and wherein said drug-releasing controlling membrane is a phase-separated membrane comprising a mixture of a crosslinked gelatin phase and the uncrosslinked segmented polyurethane phase. -63-