Evaluation of tumour and tissue distribution of porphyrins for use in photodynamic therapy

Abstract

A range of pure, monomeric porphyrins were synthesised and their localising capacities compared to HpD and Hp at 6 h and 24 h post injection in the mouse C6 intracerebral glioma model as well as in normal brain, skin, muscle, kidney, spleen, liver, lung and whole blood. The partition coefficients were examined between PBS and 2-octanol over the pH range 7.4-6.6 and pH profiles were established. A parabolic relationship was observed between log (porphyrin tumour concentration) at pH 7.4. with maximal tumour localisation at log (partition coefficient), ӆ. of approximately zero. Porphyrins with side chains with nett cationic character also exhibited an upward (parabolic) dependence on ӆ for mos..