| abstract |
A preparation for transdermal drug administration comprising a flexible backing layer and a pressure-sensitive adhesive layer containing a local anesthetic in a proportion of 40-65 weight%. Since the ratio of the amount of the undissolved local anesthetic (Ac) to that of the dissolved local anesthetic (As), Ac/As, in the pressure-sensitive adhesive layer is determined to be in the range of 0.1-1.8, the preparation for transdermal drug administration of the present invention is superior in self-adhesiveness and leaves no adhesive material upon removal from the skin. In addition, burst-like release of the undissolved drug from the pressure-sensitive adhesive layer immediately after application to the skin permits rapid appearance of the anesthetic effect, which enables wide clinical application of the preparations of the present invention. |