Applications of high-voltage paper electrophoresis for the characterization of drug metabolites

Abstract

1. The application of high-voltage paper electrophoresis (h.v.p.e.) to the identification of drug metabolites in urine and bile has been investigated.

2. The major urinary metabolite of [³H]salbutamol in man had an electrophoretic mobility indicative of a sulphate ester.

3. A metabolite of [¹⁴C]ranitidine present in rat bile was shown to contain an ionized group with a pK_a corresponding to a carboxylic acid.

4. The electrophoretic mobility-pH profile of a metabolite of radiolabelled N-cyano-(dimethylaminomethyl)-2-furanylmethylthio]ethyl] -N-methylguanidine (¹⁴C-AH 18801) excreted in dog urine suggested that oxidation of the tertiary amine group of the compound had occurred.

5. H.v.p.e. provided valuable information on the structure of both phase I and phase II metabolites at a stage when the material was insufficiently pure for identification by other techniques.