EVALUATION OF NEW BENZOPORPHYRIN DERIVATIVES WITH ENHANCED PDT EFFICACY*

Abstract— A first report on the biological evaluation of a series of isomerically pure benzoporphyrin derivatives (cis‐ and frarcs‐isomers) as methyl esters is described. In preliminary in vivo studies, the n‐bexyl ether analogues of both cis‐ and trans‐isomers of benzoporphyrin derivatives were found to be more active than the industrially prepared benzoporphyrin derivative, a mixture of monocarboxylic acids (BPDMA, Quadralogic Technologies, Vancouver). Further studies with 4‐de‐vinyl‐4‐(I‐hexyloxyethyl) benzoporphyrin derivative showed that, like BPDMA, it had reduced residual skin phototoxicity compared in mice with Photofrin®. The uptake and clearance characteristics of BPDMA were also compared with the 4‐(1‐hexyloxyethyl)‐derivative by in vivo reflection spectroscopy.