[Biotransformation of doxylamine: isolation, identification and synthesis of some metabolites (author's transl)].

After administration of therapeutic doses of doxylamine, the unchanged drug(I) and five degradation products were detected in human urine; their chemical structures are discussed and - to some extent - confirmed by synthesis. The results show that biotransformation of doxylamine in man takes place by the following routes: successive dealkylations at the nitrogen atom, giving N-demethyl-doxylamine(II) and N.N-didemethyl-doxylamine(II); cleavage at the benzhydrylether-function, resulting in the formation of 1-phenyl-1-(2-pyridyl)-ethanol(V), 1-phenyl-1-(2-pyridyl)-ethane(VI) and 1-phenyl-1-(2-pyridyl)-ethene(VII). VI and VII may be artefacts. Identification of an additional degradation product(=IV) was not possible, because the isolated quantities were too small. The analytical properties (hydrolysis!) of the pure substance and free base are thoroughly discussed, as well as the role of Chemical Ionization Mass Spectrometry with various reagent gases for the examination of biological extracts.