title: A gas-liquid chromatographic method for the determination of naltrexone and beta-naltrexol in human urine.
abstract: A rapid quantitative method was developed to assay in urine naltrexone and its major urinary metabolite, beta-naltrexol. Following solvent extraction and elimination of interfering materials, the weakly basic drug, its metabolite and the internal standard (etorphine) were silylated and analyzed by gas-liquid chromatography. As little as 0.02 mug/ml of naltrexone and beta-naltrexol was detectable using a hydrogen flame ionization detector. Twenty-four-hour urine samples were analyzed from three subjects taking 180 mg naltrexone daily. The major urinary excretion product was beta-naltrexol which accounted for 48.6% of the administered dose. Only 5% of the administered dose excreted in the urine was naltrexone. Beta-naltrexol was excreted 70% as free drug and 30% conjugated while naltrexone was 90% conjugated.
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D005048:Etorphine / Q000652:urine; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009270:Naloxone / Q000031:analogs & derivatives*; D009271:Naltrexone / Q000031:analogs & derivatives / Q000378:metabolism / Q000652:urine*; D012997:Solvents
chemical_list: D012997:Solvents; D009270:Naloxone; D005048:Etorphine; C010410:6 beta-hydroxynaltrexone; D009271:Naltrexone