Chlorpromazine metabolism. I. Quantitative fluorometric method for 11 chlorpromazine metabolites

Determination of chlorpromazine and its major metabolites by gas chromatography/mass spectrometry: application to biological fluids

A method for the quantitative determination of chlorpromazine and five of its major metabolites in a single sample of biological fluid in the ng/ml range has been developed utilizing gas chromatography/mass spectrometry with selected ion recording. The assay is highly specific and quantification is accomplished by an inverse stable isotope dilution technique, using deuterium-labeled variants of the compounds as internal standards. In this way the concentrations of chlorpromazine and five of its major metabolites (the sulfoxide, the N-oxide, the monodemethylated, the didemethylated, and the 7-hydroxylated compounds) can be determined in biological fluids. Levels in humans have been measured both in plasma and in red blood cells and are compared to those found in related in vitro studies.

A TLC fluorescence derivatization assay for chlorpromazine and its non-conjugated hepatic microsomal metabolites

Procedures for the assay of chlorpromazine (CPZ) and its metabolites were compared. An improved assay, involving organic extraction, thin-layer chromatography and fluorescence derivatization, was developed. The compounds were extracted from microsomal protein suspensions into 15% n-propanol in dichloromethane by successive extractions at pH 2 and pH 12. CPZ and its mono- and di-desmethyl, 7-hydroxy, N-oxide, sulphoxide and N-oxide-sulphoxide metabolites were separated using TLC on silica gel developed with methanol-acetone-ammonia (50:50:1 v/v/v). The compounds were extracted from the TLC plate with chloroform-methanol (2:1 v/v) and subjected to oxidation with hydrogen peroxide. The highly fluorescent oxidized derivatives were identified as sulphoxides by their fluorescence characteristics. Amounts of derivatized CPZ and metabolites were measured using derivatized promazine as the internal standard.

Chlorpromazine metabolism IV: quaternization as a key to determination of picomoles of chlorpromazine and other tertiary amine drugs

Reaction of chlorpromazine with 9-bromomethylacridine under appropriate conditions yields a nonfluorescent quaternary ammonium derivative which, on subsequent photolysis, liberates fluorescence. The major component of this fluorescence is 9-methylacridine (86%), while two minor components are 9-acridinecarboxaldehyde (6%) and 9-acridinemethanol (8%). The mechanism of photolysis leading to formation of these products appears to involve homolytic as well as heterolytic cleavages of the quaternary salt. Both the quaternization and the photolysis are stoichiometric. Appropriate isolation of the fluorescence and its quantitative determination constitutes the basis of a new and highly sensitive assay applicable to chlorpromazine and other tertiary amine drugs.