Effect of photosensitizer delivery system and irradiation parameters on the efficiency of photodynamic therapy of B16 pigmented melanoma in mice.

Abstract

Previous studies (Biolo et al., Photochem. Photobiol. 59, 362-365, 1994) showed that liposome-delivered Si(IV)-naphthalocyanine (SiNc) photosensitizes B16 pigmented melanoma subcutaneously transplanted in C57 mice to the action of 776 nm light. However, the efficacy of the phototreatment was limited by a lack of selectivity of tumor targeting by SiNc as well as by incomplete necrosis of the neoplastic mass. The present investigations show that the use of a different delivery system (Cremophor emulsion vs liposomes of dipalmitoylphosphatidylcholine) causes no significant increase in the selectivity of tumor targeting for three injected doses of SiNc (0.5, 1, 2 mg/kg). However, upon 776 nm light irradiation (300 mW/cm2; 520 J/cm2), the delay in the rate of tumor growth was maximal (7-8 days) for the highest naphthalocyanine dose. On the other hand, a remarkable improvement in the tumor response was obtained by inducing an intratumoral temperature increase to 44 degrees C immediately after PDT. The thermal effect appeared to be due to photoexcitation of melanin by 776 nm light (550 mW/cm2; 520 J/cm2) and subsequent partial conversion of absorbed energy into heat.

• Authors: R Biolo, G Jori, M Soncin, B Rihter, M E Kenney, M A Rodgers
• Journal: Photochemistry and photobiology (Photochem Photobiol) Vol. 63 Issue 2 Pg. 224-8 (Feb 1996) ISSN: 0031-8655 [Print] United States
• PMID: 8657736 (Publication Type: Comparative Study, Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Drug Carriers
• Liposomes
• Photosensitizing Agents

Topics

• Animals
• Drug Carriers
• Female
• Liposomes
• Melanoma, Experimental (drug therapy, metabolism)
• Mice
• Mice, Inbred C57BL
• Neoplasm Transplantation
• Photochemotherapy (methods)
• Photosensitizing Agents (administration & dosage, pharmacokinetics)