Identification of the metabolites of erythro-9-(2-hydroxy-3-nonyl)hypoxanthine from laboratory animals

After administration of erythro-9-(2-hydroxy-3-nonyl)hypoxanthine, eight compounds were isolated from the urine of rats, dogs, and monkeys. All of the drug metabolites were modified on the nonyl side chain. The oxidatively degraded metabolites included an alcohol (9-(2,8-dihydroxy-3-nonyl)hypoxanthine), the corresponding ketone (erythro-9-(2-hydroxy-8-keto-3-nonyl)hypoxanthine), and three carboxylic acids [erythro-6-hydroxy-5-(9- hypoxanthyl ) hepanoic acid, erythro-7-hydroxy-6-(9- hypoxanthyl )octanoic acid, and erythro-8-hydroxy-7-(9- hypoxanthyl )nonanoic acid]. Glucuronide conjugates of the unchanged drug and the alcohol metabolite were also found. The alcohol, ketone, and nonanoic acid metabolites were produced by all three species. Only the rat produced the shorter chain acid derivatives and no glucuronides. The monkey excreted both glucuronides, while dogs formed one glucuronide conjugate, that of the parent drug.