Patent ID: 8692014

Claim:
A method of photodynamic treatment of a disorder or abnormality which is responsive to photodynamic therapy, said method comprising administering to the affected area an acid addition salt of a 5-aminolevulinic acid (5-ALA) ester with an acid selected from nitric acid, sulfonic acid, and a sulfonic acid derivative, wherein the 5-ALA ester is a compound of formula I: R 2 2 N—CH 2 COCH 2 —CH 2 CO—OR 1 (I) wherein R 1 represents a straight-chained C 1-6 alkyl group optionally substituted by an aryl group, and R 2 each independently represents a hydrogen atom or an optionally substituted straight-chained, branched or cyclic alkyl group which may optionally be interrupted by one or more —O—, —NR 3 —, —S— or —PR 3 — groups; and R 3 is a hydrogen atom or a C 1-6 alkyl group, optionally together with at least one pharmaceutically acceptable carrier or excipient, and exposing said surfaces to light.