The metabolism of 2-hydroxymethyl-3-methylquinoxaline-di-N-oxide in the chicken, rat, and dog

2-Hydroxymethyl-3-methylquinoxaline-di-N-oxide (GS-7443) is rapidly metabolized in the chicken, rat, and dog to 3-carboxy-2-methylquinoxaline-1-oxide and a conjugate of 3-carboxy-2-methylquinoxaline-di-N-oxide. No appreciable amounts of other metabolites nor unchanged GS-7443 could be detected in the excreta from these animals. There were minor quantitative differences in the relative amounts of the two metabolites; moreover, the conjugating group employed by the chicken is different from that of the dog but the material being conjugated is the same. Although measurable tissue levels of drug-related material were noted in several organs of the chicken 6 day s after drug administration, all chicken tissues examined were cleared of radioactivity within 21 days.