title: A high-performance liquid chromatographic method for determination of the niguldipine analogue DHP-014.
abstract: A simple and reliable reversed-phase high-performance liquid chromatography method was developed and validated for the determination of DHP-014, a niguldipine analogue with potent P-glycoprotein inhibitory and negligible calcium channel blocking properties, in rat plasma. DHP-014 and niguldipine hydrochloride (the internal standard) were extracted from rat plasma by liquid extraction using hexane. DHP-014 was then separated by HPLC on a C18 column and quantified by ultraviolet detection at 238 nm. The mobile phase consisted of acetonitrile-aqueous 5 mM phosphate buffer (65:35, v/v) containing 0.4% (v/v) triethylamine adjusted to pH 7.0. The mean extraction efficiency of DHP-014 was 109.0 +/- 12.9, 97.7 +/- 8.0 and 102.9 +/- 7.5% for DHP-014 concentrations of 10, 50 and 100 nM, respectively (n = 5). The method was linear over the concentration range 2.5-200 nM with a regression coefficient of 0.998. The limit of detection of DHP-014 in rat plasma was 1.0 nM. The intra- and inter-day coefficients of variation for DHP-014 in rat plasma were 4.7-7.9 and 6.9-9.9%, respectively. The intra- and inter-day accuracy was 98.2-99.5 and 97.9-103%, respectively. The bioanalytical technique was used to determine DHP-014 in plasma samples in a pharmacokinetic study of DHP-014 administered to female Sprague-Dawley rats.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Amherst, NY 14260, USA.
authors.forename: Xiao-fei
authors.initials: XF
authors.lastname: Zhou
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Robert A
authors.initials: RA
authors.lastname: Coburn
authors.forename: Marilyn E
authors.initials: ME
authors.lastname: Morris
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004095:Dihydropyridines / Q000097:blood* / Q000493:pharmacokinetics; D005260:Female; D051381:Rats; D017207:Rats, Sprague-Dawley; D012015:Reference Standards; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet
chemical_list: C507547:DHP-014; D004095:Dihydropyridines