Investigation of protoporphyrin IX production induced by aminolevulinic acid combined with thermogenic and/or vasodilator substances

One of the limiting factors of photodynamic therapy is cutaneous permeation of a photosensitizer or precursor. Studies report that there is a strong relationship between temperature and porphyrin synthesis in biological tissue. The use of thermogenic and/or vasodilator substances may favor both ALA/methyl-ALA permeation and protoporphyrin IX (PpIX) production in the tissue. In this study, menthol, methyl nicotinate, and ginger extract were incorporated into either the ALA or methyl-ALA cream to investigate the PpIX production in rat skin. Fluorescence spectra were collected to quantify the PpIX present in tissues. The methyl nicotinate was the one with the highest optimization effect of PpIX production after three hours of incubation of the cream. Its association with methyl-ALA caused the production to be about 50% higher than that observed for methyl-ALA alone. These results are promising as a possible strategy for decreasing the incubation time of the precursor cream in various clinical protocols and increasing the photosensitizer production in lesions.