Comparative in vitro percutaneous penetration of 5-aminolevulinic acid and two of its esters through excised hairless mouse skin
Article first published online: 25 AUG 2003
Copyright © 2003 Wiley-Liss, Inc.
Lasers in Surgery and Medicine
Volume 33, Issue 3, pages 173–181, September 2003
How to Cite
van den Akker, J. T.H.M., Holroyd, J. A., Vernon, D. I., Sterenborg, H. J.C.M. and Brown, S. B. (2003), Comparative in vitro percutaneous penetration of 5-aminolevulinic acid and two of its esters through excised hairless mouse skin. Lasers Surg. Med., 33: 173–181. doi: 10.1002/lsm.10212
- Issue published online: 25 AUG 2003
- Article first published online: 25 AUG 2003
- Manuscript Accepted: 11 JUN 2003
- Yorkshire Cancer Research
- 5-aminolevulinic acid;
- 5-aminolevulinic acid hexyl ester;
- 5-aminolevulinic acid methyl ester;
- percutaneous penetration
Background and Objectives
ALA esters have been developed to improve PpIX production in ALA–PDT, but they do not perform as well in skin as they do in cells and the bladder.
Study Design/Materials and Methods
The in vitro penetration across normal mouse skin of ALA and its methyl and hexyl ester was determined for different application concentrations. ALA and the esters were also applied to tape stripped skin to determine the effect of the stratum corneum.
The penetration of ALA and the esters was higher through tape stripped skin than through normal skin (P < 0.01), showing that the stratum corneum is an important barrier. The experiments with different application concentrations indicated that the skin penetration through normal skin and tape stripped skin is highest for ALA and lowest for the hexyl ester.
The differences in skin penetration properties could be (co-)responsible for the finding that ALA esters do not induce substantially higher PpIX levels in in vivo skin. Lasers Surg. Med. 33:173–181, 2003. © 2003 Wiley-Liss, Inc.