Radioimmunoassay for prochlorperazine in human plasma.

A new sensitive, specific, and rapid radioimmunoassay procedure for the determination of plasma concentrations of the antiemetic drug prochlorperazine is described. The assay enables the quantitation of 31 pg of the drug in 200 microliters of plasma with a coefficient of variation of approximately 2%. Except for N-desmethylprochlorperazine, the antiserum did not cross-react with the available metabolites tested. Also there was no cross-reactivity with the tricyclic antidepressants and antianxiety agents commonly co-administered with the drug. The method is suitable for single-dose pharmacokinetic and bioavailability studies. It should be adequate for the therapeutic monitoring of the drug in patients.