Spectrofluorimetric analysis in vivo: applications to kinetics of ALA-induced fluorescence

We designed a laser spectrofluorimeter to determine the optimal delay between drug injection and laser irradiation in which both excitation and fluorescence emission are transmitted through a single optic fiber. Preclinical studies were performed in nude mice after ALA administration. The maximum fluorescence (632 nm) in HT 29 tumors was obtained after 90 min (excitation 488 nm, 20 mW, integration time 3 sec, ALA 250 mg/kg), after 180 min in liver. Iron chelators as EDTA (10 or 20 mg/kg) or desferrioxamine (20 or 40 mg/kg) increased the delay for reaching maximum fluorescence to 2 hours as well as fluorescence intensity in tumors but decreased intensity in liver. Desferrioxamine induced the appearance of protoporphyrin IX in the bladder or kidneys, normally absent in urines. These results indicate that drug distribution varies with tissues and also adjuvant therapies that are often administered together with cancer drugs.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.