Pharmacological Reviews, Vol 34, 73-76, Copyright © 1982 by American Society for Pharmacology and Experimental Therapeutics
Disposition of drugs in man by radioimmunoassay
S Spector
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.
