Quenching of singlet oxygen by haematoporphyrin derivative (and haematoporphyrin) and its consequences on the efficiency of photodynamic cancer therapy

Abstract
Haematoporphyrin derivative used in photodynamic therapy and haematoporphyrin quench singlet oxygen that they produce (rate constants 5 × 108 and 8 × 108 dm3 mol–1 s–1, respectively) with the consequence that in photodynamic therapy an increase of the sensitizer concentration may induce a very noticeable reduction of the efficiency of the photo-oxidative damage to tumour cells.