Premium
In vitro PHOTODEGRADATION OF CHLORPROMAZINE
Author(s) -
Broeke L. T. van den,
Ouijja E. H.,
Bojarski J.,
Henegouwen G. M. J. Beyersbergen VAN
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.tb05013.x
Subject(s) - photodegradation , chemistry , in vivo , photochemistry , aqueous solution , chlorpromazine , in vitro , irradiation , phototoxicity , promazine , degradation (telecommunications) , photodissociation , biophysics , photocatalysis , biochemistry , organic chemistry , catalysis , pharmacology , medicine , telecommunications , physics , microbiology and biotechnology , computer science , nuclear physics , biology
The in vitro photodecomposition of chlorpromazine (CPZ) was investigated with the aim to evaluate possible reactive determinants that could play a role in the occurrence of the in vivo ‐observed photosensitivity. In view of the in vivo situation, CPZ was dissolved in low concentration in buffered aqueous solution (pH 7.4) or in dilute human serum and irradiated with low intensity (5–7 W m ‐2 ) UV‐A and UV‐B. No distinct difference was found between UV‐A or UV‐B irradiation as far as photoproduct formation is concerned. This suggests the same degradation mechanism at both wavelength ranges. In buffered aqueous solution, irradiation of CPZ resulted in 65 and 90% 2‐hydroxypromazine (PZOH), 5 and 7% promazine (PZH) and 2 and 0% chlorpromazinesulfoxide (CPZSO) under aerobic and anaerobic conditions, respectively. In dilute human serum, there was only a shift in the PZH/PZOH ratio, probably as a result of H‐atom or electron donation by sulfur containing groups present in proteins. The results demonstrate that photodegradation of CPZ in vitro , under conditions relevant to the in vivo situation, proceeds almost entirely by dechlorination rather than by radical cation formation (the essential pathway of CPZSO production). Thus we conclude that the thiyl radical cation probably does not play a major role in the in vivo ‐observed phototoxic reactions.