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A HCl/alcohol formulation increased 5‐aminolevulinic acid skin distribution using an ex vivo full thickness porcine skin model
Author(s) -
Maisch Tim,
Worlicek Christine,
Babilas Philipp,
Landthaler Michael,
Szeimies RolfMarkus
Publication year - 2008
Publication title -
experimental dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 96
eISSN - 1600-0625
pISSN - 0906-6705
DOI - 10.1111/j.1600-0625.2008.00705.x
Subject(s) - ex vivo , alcohol , distribution (mathematics) , human skin , chemistry , in vivo , dermatology , biomedical engineering , medicine , chromatography , biochemistry , biology , in vitro , mathematics , mathematical analysis , microbiology and biotechnology , genetics
Topical photodynamic therapy with 5‐aminolevulinic acid (5‐ALA) is a newly established treatment modality for epithelial skin cancer. Skin distribution of different 20% 5‐ALA formulations was investigated by detection of protoporphyrin IX (PpIX) using an ex vivo porcine skin model. Fluorescence of PpIX was first detectable at 2 h after application of a 5‐ALA/HCl–alcohol solution, followed by a 5‐ALA gel ± 40% DMSO > 5‐ALA lipophilic ointment > 5‐ALA hydrophilic ointment at 4 h after application. Intensity of PpIX was 10‐fold higher after 5‐ALA/HCl–alcohol application in contrast to 5‐ALA hydrophilic ointment. Maxima of PpIX fluorescence were measured between 18 and 24 h after application. PpIX accumulation induced by 5‐ALA within the lower parts of the epidermis was increased in order of 5‐ALA hydrophilic ointment < 5‐ALA lipophilic ointment < 5‐ALA gel w/o DMSO < 5‐ALA gel with DMSO < 5‐ALA/HCl–alcohol. Illumination of skin incubated with different 5‐ALA formulations led to a marked increase of apoptotic cells in the epidermis depending on the penetration depth of the 5‐ALA formulations. A formulation containing short chain alcohols have been observed to increase the permeation and distribution of 5‐ALA. PpIX fluorescence was detected earlier yielding to photodynamic effective amounts of PpIX in the epidermis as compared with all other 5‐ALA formulations used. These data emphasizes the potential of investigating properties of new formulations using such a full thickness porcine skin model.