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PHOTODYNAMIC THERAPY OF B16 PIGMENTED MELANOMA WITH LIPOSOME‐DELIVERED Si(IV)‐NAPHTHALOCYANINE
Author(s) -
Biolo Roberta,
Jori Giulio,
Soncin Marina,
Pratesi Riccardo,
Vanni Umberto,
Rihter Boris,
Kenney Malcom E.,
Rodgers Michael A. J.
Publication year - 1994
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1994.tb05048.x
Subject(s) - photodynamic therapy , photosensitizer , melanoma , irradiation , chemistry , sinc function , liposome , photochemistry , absorbance , cancer research , protoporphyrin ix , medicine , biochemistry , physics , organic chemistry , chromatography , computer science , nuclear physics , computer vision
The possibility of extending photodynamic therapy to the treatment of highly pigmented neoplastic lesions was tested by using Si(IV)‐naphthalocyanine (SiNc) as a tumor‐localizing agent. Si(IV)‐naphthalocyanine displays intense absorbance at 776 nm (ɛ= 5 × 10 5 M −1 cm −1 ), where melanin absorption becomes weaker. As an experimental model we selected B16 pigmented melanoma subcutaneously transplanted to C57BL mice. Upon injection of 0.5 or 1 mg kg −1 of liposome‐incorporated SiNc, maximal accumulation of the photosensitizer in the tumor was observed at 24 h with recoveries of 0.35 and 0.57 μg g −1 , respectively. However, the tumor targeting by SiNc shows essentially no selectivity, since the photosensitizer concentrations in the skin (peritumoral tissue) were very similar to those found in the tumor at all postinjection times examined by us. Irradiation of SiNc‐loaded melanoma with 776 nm light from a diode laser at 24 h postinjection induces tumor necrosis and delay of tumor growth. The effect appears to be of purely photochemical nature at dose rates up to 260 mW cm −2 ; at higher dose rates, thermal effects are likely to become important.