Comparative pharmacokinetic and photodynamic studies with zinc(II) phthalocyanine in hamsters bearing an induced or transplanted rhabdomyosarcoma.
Comparative pharmacokinetic studies in hamsters bearing an induced or first-generation transplanted rhabdomyosarcoma that were injected with liposome-incorporated zinc(II) phthalocyanine (ZnPc) show a higher drug concentration in the induced tumour. The selectivity of tumour targeting is underlined by the fact that, 24 h after injection, larger amounts of ZnPc are found in the tumour than in the liver. Photodynamic therapy investigations were carried out using 673 nm light from an argon-dye laser. On the basis of different assessment criteria (changes in mean tumour diameter with time, tumour mass regression, survival time of the treated groups of animals, and histological determination of the necrotic tissue) the photosensitizing effect of ZnPc appears to be comparable for both kinds of tumour in spite of the higher uptake of photosensitizer by the induced tumour.