A high-performance liquid chromatography method is described which allows for the simultaneous determination of antipyrine, 4-hydroxyantipyrine, norantipyrine and 3-hydroxyantipyrine. Hydrolysis conditions with respect to source of glucuronidase, amount of glucuronidase, pH of incubation and addition of antioxidant to the incubation medium proved to be very critical for norantipyrine and to a lesser extent 4-hydroxyantipyrine. The method is of good sensitivity, specificity, accuracy and reproducibility. Thus, the method is well suited for detailed metabolic studies.

A sensitive and specific method for the simultaneous determination of bromisoval, carbromal, and methaqualone is described. The drugs are adsorbed from serum onto charcoal at pH 11 and eluted from it with organic solvent. The eluate is separated by high-pressure liquid-chromatography on reverse phase (RP 18) column using acetonitrile: water (26 : 74 by volume) as mobile phase. The eluted drugs are detected by uv-absorption at 210 nm. The method is sensitive, specific, precise, and accurate.