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Journal of Environmental Pathology, Toxicology and Oncology

ISSN for PRINT: 0731-8898

Institutional price:	$672.00
Issues per year:	4

Best Paper Award Selection - Editorial Board Site

2006, Volume25

546 pages

Issue price - $344.00

New Derivatives of 5-Aminolevulinic Acid for Photodynamic Therapy: Chemical Synthesis and Porphyrin Production in In Vitro and In Vivo Biological Systems

Aslak Godal
PhotoCure ASA, Hoffsveien 48, 0377 Oslo, Norway

Nils O. Nilsen
Drug Discovery Laboratory AS., Oslo, Norway

Jo Klaveness
Drug Discovery Laboratory AS., Oslo, Norway

Jon Erik Branden
PhotoCure ASA, Hoffsveien 48, 0377 Oslo, Norway

Jahn M. Nesland
Department of Pathology, The Norwegian Radium Hospital, University of Oslo, Oslo, Norway

Qian Peng, PhD
Pathology Clinic, Rikshospitalet-Radiumhospitalet HF Medical Center, Faculty Division Radiumhospitalet, University of Oslo, Montebello, N-0310 Oslo, Norway

ABSTRACT

Photodynamic therapy (PDT) has become a new treatment for several oncological and nononcological disorders. This procedure involves systemic or topical administration of a lesion-localizing photosensitizer or prodrug, followed by irradiation with visible light to cause singlet oxygen-induced damage to the target tissue. 5-aminolevulinic acid (ALA) is an endogenous precursor for several photosensitizing porphyrins formed by heme biosynthesis, and has been studied for PDT with promising results for some superficial diseases of the skin and hollow internal organs. Hydrophilic ALA has a limited ability to penetrate certain biological barriers and has a relatively low selectivity for lesions. In addition, its ability to induce intracellular porphyrins has been shown to be low compared to most esters of ALA. This stimulated a search for lipophilic derivatives of ALA to overcome the shortcomings of ALA. Thirty-two new esters of ALA were prepared and their ability to induce porphyrin formation was assessed in the WiDr human carcinoma cell line in vitro and in the normal skin of Balb/c nude mice in vivo. Branched-chain alkyl esters and substituted benzyl esters were found to be the most efficient porphyrin precursors of the compounds studied.