title: Radioimmunoassay for DS-4574, an antiallergic agent: development, evaluation, and application to human plasma samples.
abstract: A sensitive radioimmunoassay (RIA) method for DS-4574, an antiallergic drug, in plasma has been developed. As the three major metabolites have a hydroxyl group on the cyclohexyl ring, the triazole ring in the terminal part of molecule was attached to ovalbumin with a spacer of beta-chloropropionic acid succinimido ester to prepare an immunogen. Anti-DS-4574 antisera was obtained in rabbits immunized with the immunogen emulsified in Freund's complete adjuvant. The detection limit of the present RIA method was 1 mg/mL of plasma, which was 100-fold more sensitive than the HPLC method developed previously. Cross-reactivities with three major metabolites were less than 3%. The precision of the assay based on triplicate samples showed intra- and inter-assay coefficients of variations of less than 5% and 4%, respectively. This RIA method was applied to plasma samples of six volunteers who had received a single oral 10 mg dose of DS-4574. Plasma concentrations increased rapidly and reached 60 ng/mL at 0.5 h after administration. The concentration decreased to near the detection limit at 4 h postdose. The present RIA method was shown to possess adequate sensitivity to evaluate pharmacokinetic properties of the drug for clinical study, which was not possible by the HPLC method.
authors.affiliation: Drug Metabolism and Analytical Chemistry Research Center, Daiichi Pharmaceutical Co. Ltd., Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Murayama
authors.forename: M
authors.initials: M
authors.lastname: Nakaoka
authors.forename: H
authors.initials: H
authors.lastname: Nomura
authors.forename: H
authors.initials: H
authors.lastname: Hakusui
mesh_terms: D000328:Adult; D000818:Animals; D000918:Antibody Specificity; D003429:Cross Reactions; D006241:Haptens / Q000276:immunology; D006801:Humans; D020024:Leukotriene Antagonists; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D010047:Ovalbumin / Q000276:immunology; D011743:Pyrimidines / Q000097:blood* / Q000276:immunology / Q000493:pharmacokinetics; D011786:Quality Control; D011817:Rabbits / Q000276:immunology; D011863:Radioimmunoassay; D014230:Triazoles / Q000097:blood* / Q000276:immunology / Q000493:pharmacokinetics
chemical_list: D006241:Haptens; D020024:Leukotriene Antagonists; D011743:Pyrimidines; D014230:Triazoles; C076052:DS 4574; D010047:Ovalbumin