Photodynamic therapy of melanoma B16 in mice with the new photosensitizer boronated chlorine

Abstract

Pilot studies of pharmacokinetics and pharmacodynamics of new photosensitizer liposomal boronated chlorine in mice with melanoma В16 were performed. Dynamics of drug accumulation in tumor and normal tissue (level of accumulation in tissues was assessed by means of fl uorescence) was studied. For intraperitoneal injection at a dose of 5 mg/kg the drug was shown to accumulate gradually in tumor and normal tissues with maximal fl uorescence values in 2–3 h after injection. Then fl uorescence intensity in tissues gradually decreased, achieving nearly initial base-line in 120 h after beginning of the study. The hotosensitizer accumulated in tumor tissue with average selectivity: contrast index for maximal drug accumulation in tissues accounted for 1.7–2.8. According to obtained data for following research the time interval between drug injection and irradiation of 3h was chosen. On the second stage of the study dependence of photodynamic therapy effi cacy on different parameters including photosensitizer dose for intraperitoneal injection (5–10 mg/kg), light dose (150–300 J/cm 2 ) and power density (0.25–0.51 mW/cm 2 ). The irradiation was performed by semiconductor laser on wavelength of 662±1 nm. The effi cacy was maximal for following regimen: photosensitizer dose of 5 mg/kg, light dose of 300 J/cm 2 , power intensity of 0.44 mW/cm 2 . For this regimen at the end of follow-up (21 days) complete tumor regression was obtained in 75% of animals and average coeffi cient of absolute tumor growth accounted for only 7.82.