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RADIOSENSITISING NITROIMIDAZOLE DRUGS: TRIPLET STATE ENERGY AND REACTIVITY
Author(s) -
Kemp Terence J.,
Parker Anthony W.,
Wardman Peter
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.tb07395.x
Subject(s) - flash photolysis , excited state , triplet state , chemistry , quenching (fluorescence) , misonidazole , reactivity (psychology) , metronidazole , photochemistry , fluorescence , atomic physics , antibiotics , molecule , reaction rate constant , medicine , kinetics , organic chemistry , in vitro , biochemistry , physics , alternative medicine , quantum mechanics , pathology
— Although the radiosensitising drugs metronidazole 1 and misonidazole 2 neither phosphoresce nor yield triplet‐triplet absorption in the region 350–700 nm, it is, nevertheless, possible to determine their triplet state energies E T by kinetic quenching methods using laser flash photolysis, and also by a steady‐state method due to Ullman depending on sensitisation of a colour reaction. Both approaches give acceptable concordance, with figures of 244±4 kJ mol ‐1 for both 1 and 2. These lead to estimates of triplet excited state one‐electron reduction potentials for 1 and 2 in water of 2.04 and 2.14 V vs NHE, enabling an assessment of the possible role of excited 1 and 2 in radiosensitisation.