PT - JOURNAL ARTICLE AU - S Spector TI - Disposition of drugs in man by radioimmunoassay. DP - 1982 Mar 01 TA - Pharmacological Reviews PG - 73--76 VI - 34 IP - 1 4099 - http://pharmrev.aspetjournals.org/content/34/1/73.short 4100 - http://pharmrev.aspetjournals.org/content/34/1/73.full SO - Pharmacol Rev1982 Mar 01; 34 AB - The disposition of morphine and clonidine was investigated by means of radioimmunoassay. After the administration of a single i.v. dose of morphine (10 mg/70 kg) to 10 men who had not received other drugs for two weeks preceding the study, a multiphasic decline in serum concentrations of morphine occurred. Detectable blood concentrations of morphine, or a metabolite, or of both, persisted for up to 96 hours after a single i.v. dose. The radioimmunoassay for clonidine is capable of detecting as little as 10 pg of clonidine. The antibody fails to bind 2,6-dichlorophenylguanidine, a known metabolite of clonidine, while the other metabolite, 4-hydroxyclonidine, was as potent as clonidine in displacing labeled clonidine from the antibody. The disposition of clonidine ion plasma and tissues could be monitored by radioimmunoassay.