ABSORPTION-SPECTRUM OF HEMATOPORPHYRIN DERIVATIVE IN-VIVO IN A MURINETUMOR-MODEL

Time-resolved reflectance was used to measure the absorption spectrum of hematoporphyrin derivative (HpD) in vivo in a murine tumor model. R eflectance measurements were performed in the 600-640 nm range on mice bearing the L1210 leukemia. Then the animals were administered 25 mg/ kg body weight of HpD intraperitoneally. One hour later the reflectanc e measurements were repeated. Fitting of the data using the diffusion theory allowed assessment of the absorption coefficient before and aft er the administration. As a difference between the latter and the form er data, the in vivo absorption spectrum of HpD was evaluated. Maximum absorption was measured at 620-625 nm. Similar spectral behavior was obtained for HpD in solution in the presence of low-density lipoprotei ns.