水溶性食物繊維より調製したプリロカイン‐リドカイン含有ヒドロゲルパッチ（ＰＬパッチ）の皮膚吸収性および有用性の評価

Abstract

New hydrogel patches (PL patches) containing local anesthetics were developed. The percutaneous absorption and usefulness of the PL patches prepared with water-soluble dietary fibers, xanthan and locust bean gums, containing an eutectic mixture of prilocaine and lidocaine were investigated. The evaluation of percutaneous absorption and topical anesthetic efficacy were respectively performed by the measurement of drug concentrations in hairless rat skin and the Pin-Prick method with normal healthy volunteers. The drug concentrations in hairless rat skin greatly increased with the additives such as ethanol and l-menthol. The amount of absorbed drugs was in proportion to the increase of ethanol concentration. Adjusting purified water at pH 9.0 in the preparation of PL patches seems to be an important factor in promoting absorption of the eutectic mixture. The effect of application time suggested that the apparent absorption rate of the PL patches containing ethanol became larger after 45 min compared with PL cream used as a control. The pain scores determined by the Pin-Prick method indicated that the PL patches both prepared with purified water (adjusted at pH 9.0) containing ethanol (20%(v/v)) and including ethanol (20%(v/v)) with l-menthol (1%(w/v)) were significantly more effective than the commercial lidocaine tape and PL cream. In a clinical treatment study, the pain accompanying the removal of molluscum contagiosum was successfully blocked by the application of the PL patches. These results suggested that the PL patches prepared with water-soluble dietary fibers containing an eutectic mixture were quite useful as practical local anesthetic preparations.