TY - JOUR T1 - Disposition of drugs in man by radioimmunoassay. JF - Pharmacological Reviews JO - Pharmacol Rev SP - 73 LP - 76 VL - 34 IS - 1 AU - S Spector Y1 - 1982/03/01 UR - http://pharmrev.aspetjournals.org/content/34/1/73.abstract N2 - 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. ER -