Clearance of protoporphyrin IX from mouse skin after topical application of 5-aminolevulinic acid and its methyl ester

摘要

Abstract: The clearance of protoporphyrin IX (PpIX) from the skinof hairless BALB/c mice after topical application of 5-aminolevulinic acid (ALA) and its methyl ester (ALA-Me)was investigated. Creams containing 2 or 20% of ALA orALA-Me were topically applied on spots of approximately1 cm$+2$/ for 12 hours. The PpIX fluorescence wasdetected by the means of a Perkin Elmer LS50Bluminescence spectrometer equipped with a fiber-opticprobe. The emission spectrum was identical with that ofcell-bound PpIX. After 12 hours application of ALA andALA-Me similar amounts of PpIX were found. After cremeremoval the ALA-induced PpIX fluorescence decayed witha half-life of about 20 hours (20% ALA cream). TheALA-Me-induced PpIX was faster cleared from the skinthan ALA-induced PpIX, and had a half-life of about 7hours (20% ALA-Me cream). !18