Non-human primate species as metabolic models for the human situation: comparative studies on meperidine metabolism.

It is established that nonhuman primates in general provide better animal metabolic models of the human situation than do subprimate species. However, very little is known about interprimate variations in drug metabolism, and therefore meperidine metabolism was studied in the vervet, patas and mona monkeys and the mangabey after intramuscular injection of 5 mg/kg. Urinary metabolites were analyzed by gas-liquid chromatography, and in addition to unchanged meperidine, normeperidine, meperidine-N-oxide, meperidinic and normeperidinic acids (free and conjugated with glucuronic acid) and, in some cases, 4′-hydroxymeperidine were all detected and quantitated. The metabolic profile of meperidine in each species was compared with data from man and rat, which showed that there were considerable interprimate variations in the relative proportions of the metabolites found in its urine. The mangabey appeared to provide a good metabolic model for man, the mona and patas monkeys were less acceptable, and the vervet was unsuitable for this purpose. The metabolism of meperidine in the rat was markedly different from that in man and in the monkey species examined.