Silylation improves the photodynamic activity of tetraphenylporphyrin derivatives in vitro and in vivo.
The effects of silyl and hydrophilic groups on the photodynamic properties of tetraphenylporphyrin (TPP) derivatives have been studied in vitro and in vivo. Silylation led to an improvement in the quantum yield of singlet oxygen sensitization for both sulfo and carboxy derivatives, although the silylation did not affect other photophysical properties. Silylation also improved the cellular uptake efficiency for both sulfo and carboxy derivatives, enhancing the in vitro photodynamic activity of the photosensitizer in U251 human glioma cells. The carboxy derivative (SiTPPC4 ) was found to show higher cellular uptake efficiency and in vitro photodynamic activity than the corresponding sulfo derivative (SiTPPS4 ), which indicates that the carboxy group is a more promising hydrophilic group than the sulfo group in the silylated porphyrin. SiTPPC4 was found to show high selective accumulation efficiency in tumors, although almost no tumor selectivity was observed for the nonsilylated porphyrin. The concentration of SiTPPC4 in tumors was 13 times higher than that in muscle 12 h after drug administration. We also studied tumor response after treatment and found that silylation enhanced in vivo photodynamic activity significantly. SiTPPC4 shows higher photodynamic activity than NPe6 with white light irradiation.
Division of Molecular Science and International Education and Research Center for Silicon Science, Faculty of Science and Technology, Gunma University, Kiryu (Japan), Fax: (+81) 277-30-1244. hhoriuchi@gunma-u.ac.jp.
Hiroaki
H
Horiuchi
Masahiro
M
Hosaka
Hiroyuki
H
Mashio
Motoki
M
Terata
Shintaro
S
Ishida
Soichiro
S
Kyushin
Tetsuo
T
Okutsu
Toshiyuki
T
Takeuchi
Hiroshi
H
Hiratsuka
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000473:pathology; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D005260:Female; D005453:Fluorescence; D005910:Glioma / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D011166:Porphyrins / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D012821:Silanes / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use
D017319:Photosensitizing Agents; D011166:Porphyrins; D012821:Silanes; C409084:tetraphenylporphyrin
biological activity; fluorescence; photodynamic therapy; porphyrinoids; silylation