Finasteride為5-αreductase isoenzyme type II之抑制劑，目前有口服錠劑用於治療良性攝護腺增生(Benign Prostatic Hypertrophy)及雄性禿(male pattern baldness)但尚無皮膚用之軟膏藥劑，本研究選擇不含水之FAPG(fatty alcohol propylene glycol)與含水之水性凝膠為基劑做相關黏度、體外藥物釋離、安定性等實驗並以大白鼠做相關皮膚體外藥物透皮、體內藥物經皮、藥物在皮膚及去角質層皮膚殘存量、皮膚及肝臟粗酵素抽出液的體外代謝實驗等研究。研究中發現finasteride凝膠比FAPG軟膏有較大之黏度及較慢之藥物釋離，但有較大的藥物透皮速率(rate of penetration)，凝膠劑經皮吸收後藥物在血液與皮膚中之藥物濃度均為FAPG軟膏之2至3倍。Finasteride皮膚藥劑施藥後第三天藥物在皮膚中之累積量有顯著的增加，這使藥物在移除後仍可維持一段時間之藥效，這有助於藥物滯留在毛囊中促進毛髮成長之藥效。Finasteride在皮膚中不生代謝現象，在藥物安定性上FAPG軟膏劑則比凝膠劑安定，其架貯期為48.1±5.3天，凝膠劑則為34.7±4.6天。 Finasteride is an orally active agent for treatment of benign prostatic hypertrophy and male pattern baldness. The properties of the percutaneous absorption of finasteride from ointment has not yet been study. The Gels and FAPG (fatty alcohol propylene glycol) were selected as the ointment base for finasteride in this study. The properties of viscosities of ointment, drug released from ointment through cellulose membrane and rat skin in vitro, the stability of finasteride in ointment, the percutaneous absorption of finasteride in rat, residued drug in skin after applied of the drug, the metabolism of finasteride in rat skin and liver in vitro were studied respectively. It was found that the finasteride released from the Gels was slower than that of FAPG. However, the rate of percutaneous absorption of finasteride ointment in rat was greater than that of FAPG. The plasma concentration of finasteride and the residued finasteride in skin after applied of the Gels was three fold greater than that of FAPG. During the period of drug applied, the finasteride was gradually ccumulated into the skin and especially after 48 h continuous applied. It was also found that the finasteride had no metabolism in the rat skin according to the study of metabolism in vitro. The shelf life of the Gels of finasteride, 34.7 days, was shorter than that of FAPG, 48.1 days.
