Topical application of ALA and ALA hexyl ester on a subcutaneous murine mammary adenocarcinoma: Tissue distribution

PEROTTI, C.; CASAS, A.; FUKUDA, H.; SACCA, P.; BATLLE, A.

BRITISH JOURNAL OF CANCER

NATURE PUBLISHING GROUP

Año: 2003 vol. 88 p. 432 - 437

0007-0920

Although 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT) has proven to be clinically beneficial for the treatment of certain cancers, including a variety of skin cancers, optimal tissue localisation still remains a problem. An approach to improve the bioavailability of protoporphyrin IX (PplX) is the use of ALA derivatives instead of ALA. In this work, we employed a subcutaneous murine mammary adenocarcinoma to study the tissue distribution pattern of the ALA hexyl ester (He-ALA) in comparison with ALA after their topical application in different vehicles. He-ALA induced porphyrin synthesis in the skin overlying the tumour (SOT), but it did not reach the tumour tissue as effciently. Only 5 h after He-ALA lotion application, tumour porphyrin levels surpassed control values. He-ALA delivered in cream induced a substantially lower porphyrin synthesis in SOT, reinforcing the importance of the vehicle in the use of topical PDT. Porphyrin levels in internal organs remained almost within control values when He-ALA was employed. The addition of DMSO to ALA formulation slightly increased tumour and SOT porphynn biosynthesis, but it did not when added to He-ALA lotion. © 2003 Cancer Research UK.