PROBLEM TO BE SOLVED: To provide an external preparation for the skin which includes tranexamic acid dissolved stably in high concentration, exhibits high penetration of tranexamic acid into the stratum corneum even with a practically small amount of application, although externally applied tranexamic acid normally penetrates little into the stratum corneum and has lasting penetration of tranexamic acid into the stratum corneum by controlling the re-crystalization of tranexamic acid on the surface of the skin after application.SOLUTION: The external preparation for the skin is of an emulsion type and includes an aqueous phase containing tranexamic acid or its salt, an oil phase and a surfactant. The oil phase contains a higher fatty acid. The surfactant used is one kind or not less than two kinds selected from among phosphate-based anionic surfactants and/or nonionic surfactants having an HLB of 6.0-18.0. The tranexamic acid or its salt is dissolved in the aqueous phase having an adjusted pH of 4.0-6.0 in an amount of 5.0-12.0 mass% to the total amount of the external preparation for the skin.COPYRIGHT: (C)2011,JPO&INPIT【課題】外用塗布では角層透過性の低いトラネキサム酸に関して、現実的な少ない塗布量であってもトラネキサム酸の角層透過性が高く、塗布後の皮膚表面におけるトラネキサム酸の再結晶化を抑えることで角層透過の持続性に優れた高濃度トラネキサム酸を安定に溶解した皮膚外用剤を提供する。【解決手段】トラネキサム酸またはその塩を含む水相と、油相と、界面活性剤を含有する乳化型皮膚外用剤であって、油相中に高級脂肪酸を含み、界面活性剤としてリン酸エステル系のアニオン界面活性剤および/またはHLBが6.0~18.0の非イオン性界面活性剤の中から選ばれる1種または2種以上を用いるとともに、前記トラネキサム酸またはその塩を、pHを4.0~6.0に調整した水相中に、皮膚外用剤全量に対し5.0~12.0質量%の配合割合で溶解してなることを特徴とする、上記乳化型皮膚外用剤。【選択図】図5
