Inosiplex: metabolism and excretion of the dimethylaminoisopropanol and p-acetamidobenzoic acid components in rhesus monkeys.

The principal excretion products derived from radiolabeled N,N-dimethylaminoisopropanol (Dip) and p-acetamidobenzoic acid (PAcBA) components of inosiplex (Isoprinosine) were identified and quantified in urine following single iv and oral administration of the drug in rhesus monkeys. The major metabolite derived from [3H] PAcBA was identified as PAcBA-O-acylglucuronide by 1) positive naphthorescorcinol reaction for glucuronic acid and 2) hydrolysis of the metabolite to PAcBA and glucuronic acid, using either dilute base (but not acid) or beta-glucuronidase. This metabolite accounted for 50% of the administered dose in orally dosed animals and 31% in iv dosed animals. A minor metabolite, which constituted approximately 5% of the excreted 3H from either iv or orally dosed animals, was identified as the hippuric acid conjugate of PAcBA by co-chromatography with a commercial standard. A single metabolite derived from [14C]Dip was identified as Dip-N-oxide by co-chromatography with synthetic material in several chromatographic systems; this metabolite accounted for 17 to 18% of the administered 14C in either the iv or orally dosed animals.