title: Development of a sensitive liquid chromatography-electrospray ionization mass spectrometry method for the measurement of KW-5139 in rat plasma.
abstract: A sensitive method for the determination of a prokinetic peptide, KW-5139 (Leu(13)-motilin), in rat plasma has been developed utilizing liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS). KW-5139 was separated by reversed-phase HPLC, with a mixture of 75 mM ammonium formate (pH 3.0) and acetonitrile (4:1, v/v), and monitored by single ion recording (SIR)-ESI-MS at m/z 894 ([M+3H](3+)). Simple protein precipitation and the LC-ESI-MS analysis allowed the determination of KW-5139 in rat plasma with the mean precision and accuracy at the lower limit of quantitation (LLOQ, 0.5 ng/mL) of 5.7 and 11.2%, respectively. The method was applied to the monitoring of the plasma time-concentration profile of KW-5139, intravenously administered to rats at a dose of 1 microg/kg.
authors.affiliation: Drug Development Research Laboratories, Pharmaceutical Research Institute, Kyowa Hakko Kogyo Co. Ltd, 1188 Shimotogari Nagaizumi-cho, Shizuoka-ken 411, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: M
authors.initials: M
authors.lastname: Takashima
authors.forename: T
authors.initials: T
authors.lastname: Uchimura
authors.forename: S
authors.initials: S
authors.lastname: Kobayashi
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D005765:Gastrointestinal Agents / Q000097:blood*; D013058:Mass Spectrometry / Q000379:methods*; D009037:Motilin / Q000031:analogs & derivatives* / Q000097:blood; D051381:Rats; D012680:Sensitivity and Specificity
chemical_list: D005765:Gastrointestinal Agents; D009037:Motilin; C013087:13-Leu-motilin