title: Determination of an endothelin receptor antagonist in rat plasma by radioimmunoassay.
abstract: A quantitative method based on radioimmunoassay for the determination of an endothelin receptor antagonist (C(31)H(33)NO(7), I) has been developed and validated. The immunogen was prepared by coupling I to the bovine serum albumin via the N-hydroxysuccinimide ester of I from which the radioligand was also prepared by the reaction with [125I]-iodotyrosine. The method was specific and no immunoactive material other than the parent drug was detectable in mammalian plasma. This direct assay, using 50 microl of rat plasma is sensitive (0.4 ng/ml), without matrix interference, and has sufficient sensitivity, specificity, accuracy and precision for the analysis of dosed rat plasma samples.
authors.affiliation: Department of Drug Metabolism, WP 75A-203, Merck Research Laboratories, West Point, PA 19486, USA. al_yuan@merck.com
authors.forename: S
authors.initials: S
authors.lastname: Yuan
authors.forename: D
authors.initials: D
authors.lastname: Cylc
authors.forename: J Y-K
authors.initials: JY
authors.lastname: Hsieh
authors.forename: B K
authors.initials: BK
authors.lastname: Matuszewski
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D065128:Endothelin Receptor Antagonists; D005260:Female; D008297:Male; D004364:Pharmaceutical Preparations / Q000097:blood* / Q000737:chemistry; D011485:Protein Binding / Q000502:physiology; D011817:Rabbits; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats
chemical_list: D065128:Endothelin Receptor Antagonists; D004364:Pharmaceutical Preparations