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LOCALIZATION OF MONO‐L‐ASPARTYL CHLORIN e6 (NPe6) IN MOUSE TISSUES
Author(s) -
Aizawa Katsuo,
Okunaka Tetsuya,
Ohtani Takuzo,
Kawabe Hirofumi,
Yasunaka Yukari,
O'Hata Susumu,
Ohtomo Nobunari,
Nishimiya Katsuaki,
Konaka Chimori,
Kato Harubumi,
Hayata Yoshihiro,
Saito Takashi
Publication year - 1987
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.1751-1097.1987.tb04849.x
Subject(s) - photodynamic therapy , absorption (acoustics) , chemistry , fluorescence , porphyrin , chlorin , materials science , photochemistry , optics , physics , organic chemistry , composite material
It is known that HpD is retained longer by malignant tissue than normal tissue and is therefore a useful material for photodynamic therapy (PDT). Currently, vigorous research is being conducted throughout the world to discover a new material which can have greater cancer cell affinity than hematoporphyrin derivative (HpD) and will be used effectively for PDT. Investigation has been conducted to determine the spectral characteristics and cancer cell affinity of NPe6, a recently developed material. Structurally, a double bond on the D‐ring of the porphyrin ring of mono‐L‐aspartyl chlorin e6 (NPe6) has been reduced, thereby changing its spectral properties from that of HpD. This difference accounts for the stronger absorption bands in wavelengths longer than those of HpD. Furthermore, NPe6 in tumor showed stronger absorption at 660 nm than HpD. Absorption by hemoglobin (Hb) in the blood occurs at wavelengths in the range 500‐600 nm, thereby lowering light transmittance. A compound which has a strong absorption band at wavelengths longer than 600 nm and consequently is not affected by Hb will naturally be activated by light at a greater depth in tissue than compounds which do not share this characteristic. The localization of NPe6 in sarcoma and various internal organs was examined with an endoscopic spectrophotometer using an excimer dye laser. After 72 h i.v. NPe6 injection, the results indicate that NPe6 has 10 times greater uptake in malignant tissue cells than in normal organs. Based on the above observations, it was concluded that NPe6 could be effective for PDT if toxicity is low and that this compound has a high malignant tissue affinity.