title: Development and validation of a gas chromatography-mass spectrometry method for the determination of phenazopyridine in rat plasma: application to the pharmacokinetic study.
abstract: Phenazopyridine hydrochloride is a strong analgesic used in the treatment of urinary tract infections. The aim of the present study was to develop a procedure based on gas chromatography-mass spectrometry (GC-MS) for the analysis of phenazopyridine in rat plasma. The method was set up and adapted for the analysis of small biological samples taken from rats. Biological samples were extracted by liquid-liquid extraction. The extraction agent was ethyl acetate. The samples were separated by GC on a DB-5MS analytical column and determined by a quadrupole mass spectrometer detector operated under selected ion monitoring mode. Excellent linearity was found between 0.01 and 1.00 microg/ml (r = 0.9991, n = 9) for plasma samples. The limit of detection (LOD) was 0.3 ng/ml. Within-day and between-day precisions expressed as the relative standard deviation (RSD) for the method were 1.83-4.91% and 2.12-4.76%, respectively. The recoveries for all samples were >90%. The main pharmacokinetic parameters obtained were T(max) = (0.35+/-0.01) h, C(max) = (0.396+/-0.079) microg/ml, AUC = (0.373+/-0.065) h microg/ml and CL = (94.2+/-5.9) ml/g/h. The results presented here clearly indicate that this proposed method could be applicable to investigate the pharmacokinetic of phenazopyridine in rats after administration. (c)
authors.affiliation: Department of Pharmacy, Affiliated Dongfeng General Hospital, Yunyang Medical College, Shiyan, Hubei, PR China. cqh77@163.com
authors.forename: Qinhua
authors.initials: Q
authors.lastname: Chen
authors.forename: Kaijun
authors.initials: K
authors.lastname: Li
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
mesh_terms: D000779:Anesthetics, Local / Q000097:blood* / Q000493:pharmacokinetics*; D000818:Animals; D019540:Area Under Curve; D002138:Calibration; D003975:Diazepam / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D006207:Half-Life; D008297:Male; D010621:Phenazopyridine / Q000097:blood* / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012015:Reference Standards; D015203:Reproducibility of Results; D012996:Solutions
chemical_list: D000779:Anesthetics, Local; D012996:Solutions; D010621:Phenazopyridine; D003975:Diazepam