In vivo studies on the utilization of mono-L-aspartyl chlorin (NPe6) for photodynamic therapy.

The in vivo photosensitizing efficacy of mono-L-aspartyl chlorin has been studied by determining the percentage of BALB/c mice cured at varying doses of drug. Using an EMT-6 tumor model, animals received i.p. injections of mono-L-aspartyl chlorin (0.5-100 mg/kg) and then were subsequently exposed to light at 664 nm. Tumor biopsies were taken from selected animals sacrificed at 24 h after treatment and routine histopathological sections made. The other animals remained in the dark for a period of 6 weeks to determine the cure rate. Our results show that mono-L-aspartyl chlorin is an effective tumor localizer that brings about the selective degradation of tumor tissue following light exposure.