title: A rapid, simple, specific liquid chromatographic-electrospray mass spectrometry method for the determination of finasteride in human plasma and its application to pharmacokinetic study.
abstract: A fast, accurate, sensitive, selective and reliable method using reversed-phase high-performance liquid chromatography-mass spectrometry coupling with an electrospray ionization interface was developed and validated for the determination of finasteride in human plasma. After deprotienation with acetonitrile, centrifugation, evaporation to dryness and dissolving in mobile phase, satisfactory separation was achieved on a Hypersil-Keystone C(18) reversed-phase column using a mobile phase consisting of acetonitrile-water (46:54, v/v), 0.1% acetic acid and 0.1% trifluoracetic acid. Carbamazepine (IS) was used as internal standard. This method involved the use of the [M+H](+) ions of finasteride and IS at m/z 373 and 237 with the selective ion monitoring (SIM) mode. The calibration curve was linear in the range of 0.2-120 ng ml(-1). The limit of quantification for finasteride in plasma was 0.2 ng ml(-1) with good accuracy and precision. The intra-assay precision and accuracy were in the range of 2.1-11.2% and -1.3% to 8.5%, respectively. The inter-assay precision and accuracy were in the order of 3.4-12.1% and -1.5% to 11.5%, respectively. The mean sample extract recoveries of the method were higher than 85% and 74% for finasteride and internal standard (IS), respectively. The assay has been successfully used to estimate the pharmacokinetics of finasteride after oral administration of a 5mg tablet of finasteride to 24 healthy volunteers.
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, PR China.
authors.forename: Fang-Qiu
authors.initials: FQ
authors.lastname: Guo
authors.forename: Lan-Fang
authors.initials: LF
authors.lastname: Huang
authors.forename: Kin Ping
authors.initials: KP
authors.lastname: Wong
authors.forename: Yun-Hui
authors.initials: YH
authors.lastname: Dai
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Li
authors.forename: Yi-Zeng
authors.initials: YZ
authors.lastname: Liang
authors.forename: Ke-Long
authors.initials: KL
authors.lastname: Huang
authors.forename: Ke-Jun
authors.initials: KJ
authors.lastname: Zhong
authors.forename: Ming-Jian
authors.initials: MJ
authors.lastname: Wu
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D002220:Carbamazepine / Q000737:chemistry; D002853:Chromatography, Liquid / Q000295:instrumentation / Q000379:methods*; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics*; D018120:Finasteride / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D015394:Molecular Structure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013607:Tablets; D013997:Time Factors
chemical_list: D004791:Enzyme Inhibitors; D013607:Tablets; D002220:Carbamazepine; D018120:Finasteride