抄録
Stability of the deuterium-label in the p-hydroxylation of l-ephedrine [arom.-2H5] was investigated as one of problems on the applicability of this labeled compound to metabolic studies in man. p-Hydroxyephedrine liberated by enzymic hydrolysis from its glucuronide in the 24-hr urine of rats injected deuterated l-ephedrine (97.9 atom% 2H) was purified and oxidized to p-hydroxybenzoic acid. The deuterium content on the aromatic ring of the latter compound was found to be 98.1 atom% 2H by determining accurately by mass spectrometry. This fact indicates that the deuterium-label at meta and ortho positions of the substrate was retained during the p-hydroxylation and that the deuterium-label of the resulting p-hydroxyephedrine was stable during the glucuronide formation and the subsequent enzymic hydrolysis of the glucuronide to its free form.
