Derivatives of natural tetrapyrroles for photodynamic therapy, 3. Oxidative degradation studies on porphyrins with chromic acid

Until now the composition of the complex porphyrin mixtures of hematoporphyrin derivative (HPD) and Photofrin II could not be clarified in detail. We investigated the applicability of oxidative degradation to the structural assignment of HPD constituents. Therefore, some fundamental work concerning the characterization of the relevant degradation products had to be done. In this article we present the spectral and analytical data of monomeric and dimeric maleimides potentially arising from the corresponding constituents of HPD.