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| PHOTOPHYSICAL AND PHOTOSENSITIZING PROPERTIES OF BENZOPORPHYRIN DERIVATIVE MONOACID RING-A (BPD-MA) |
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| Author(s): AVELINE B, HASAN T, REDMOND RW |
| Source: PHOTOCHEMISTRY AND PHOTOBIOLOGY Volume: 59 Issue: 3 Pages: 328-335 Published: MAR 1994 |
| Times Cited: 105 References: 35 |
| Abstract: The photophysical properties of benzoporphyrin derivative monoacid ring A (BPD-MA), a second-generation photosensitizer currently in phase II clinical trials, were investigated in homogeneous solution. Absorption, fluorescence, triplet-state, singlet oxygen (O-2 ((1) Delta(g))) sensitization studies and photobleaching experiments are reported. The ground state of this chlorin-type molecule shows a strong absorbance in the red (lambda approximate to 688 nm, epsilon approximate to 33 000 M(-1) cm(-1) in organic solvents). For the singlet excited state the following data were determined in methanol: energy level, E(S) = 42.1 kcal mol(-1), lifetime, tau(f) = 5.2 ns and fluorescence quantum yield, Phi(f) = 0.05 in air-saturated solution. The triplet state of BPD-MA has a lifetime, tau(T) greater than or equal to 25 mu s, an energy level, E(T) = 26.9 kcal mol(-1) and the molar absorption coefficient is epsilon T = 26 650 M(-1) cm(-1) at 720 nm. A dramatic effect of oxygen on the fluorescence (Phi(f)) and intersystem crossing (Phi(T)) quantum yields has been observed. The BPD-MA presents rather high triplet (Phi(T) = 0.68 under N-2-saturated conditions) and singlet oxygen (Phi(Delta) = 0.78) quantum yields. On the other hand, the presence of oxygen does not significantly modify the photobleaching of this photostable compound, the photodegradation quantum yield (Phi(Pb)) of which was found to be on the order of 5 x 10(-5) in organic solvents. |
| Document Type: Article |
| Language: English |
Addresses:
1. HARVARD UNIV, MASSACHUSETTS GEN HOSP, SCH MED, DEPT DERMATOL, WELLMAN LAB PHOTOMED, BOSTON, MA 02114 USA |
| Publisher: AMER SOC PHOTOBIOLOGY, BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 |
| Subject Category: Biochemistry & Molecular Biology; Biophysics |
| IDS Number: NF318 |
| ISSN: 0031-8655 |
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