title: Determination of the substance P receptor antagonist CP-122,721 in plasma by narrow-bore high-performance liquid chromatography-ionspray tandem mass spectrometry.
abstract: A simple, highly sensitive and specific LC-MS-MS assay was developed for the determination of CP-122,721 (I) in rat and human plasma. I and a structural analog, CP-129,943 (II, internal standard), were extracted from plasma with methyl tert.-butyl ether (MTBE). The dried MTBE extracts were reconstituted and analyzed using a narrow-bore (2.1 mm I.D.) YMC basic HPLC column and a mobile phase of acetonitrile-20 mM ammonium acetate, pH 5 (50:50, v/v). Column effluents were monitored by ionspray tandem mass spectrometry. Multiple reaction monitoring (MRM) using the parent to product ion combinations of m/z 381-->205 and 395-->219 was used to quantitate I and II, respectively. The assay exhibited a linear dynamic range of 0.2-100 ng/ml. Absolute recoveries from plasma were above 80% for both I and II. The precision and accuracy values for the method were within +/-3 and +/-9%, respectively. Sample analysis times were less than 5 min from one injection to the next. The assay has proved to be applicable to the pharmacokinetic study of I in rats.
authors.affiliation: Department of Drug Metabolism, Pfizer Inc., Groton, CT 06340, USA.
authors.forename: A
authors.initials: A
authors.lastname: Kamel
authors.forename: C
authors.initials: C
authors.lastname: Prakash
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D006801:Humans; D013058:Mass Spectrometry; D064729:Neurokinin-1 Receptor Antagonists; D010880:Piperidines / Q000097:blood* / Q000493:pharmacokinetics; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D064729:Neurokinin-1 Receptor Antagonists; D010880:Piperidines; C099414:(2S,3S)-2-phenyl-3-((5-trifluoromethoxy-2-methoxy)benzylamino)piperidine