title: High-throughput determination of carbocysteine in human plasma by liquid chromatography/tandem mass spectrometry: application to a bioequivalence study of two formulations in healthy volunteers.
abstract: A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method to determine carbocysteine in human plasma was developed and fully validated. After methanol-induced protein precipitation of the plasma samples, carbocysteine was subjected to LC/MS/MS analysis using electrospray ionization (ESI). The MS system was operated in the selected ion monitoring (SRM) mode. Chromatographic separation was performed on a Hypurity C18 column (i.d. 2.1 mm x 50 mm, particle size 5 microm). The method had a chromatographic running time of 2.0 min and linear calibration curves over the concentration ranges of 0.1-20 microg/mL for carbocysteine. The lower limit of quantification (LLOQ) of the method was 0.1 microg/mL for carbocysteine. The intra- and inter-day precision was less than 7% for all quality control samples at concentrations of 0.5, 2.0, and 10.0 microg/mL. These results indicate that the method was efficient with a simple preparation procedure and a very short running time (2.0 min) for carbocysteine compared with methods reported in the literature and had high selectivity, acceptable accuracy, precision and sensitivity. The validated LC/MS/MS method has been successfully used to a bioequivalence study of two tablet formulations of carbocysteine in healthy volunteers.
authors.affiliation: Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, 74 Zhongshan Road II, Guangzhou 510080, China.
authors.forename: Hui-Chang
authors.initials: HC
authors.lastname: Bi
authors.forename: Li-zi
authors.initials: LZ
authors.lastname: Zhao
authors.forename: Guo-ping
authors.initials: GP
authors.lastname: Zhong
authors.forename: Shufeng
authors.initials: S
authors.lastname: Zhou
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Deng
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.forename: Min
authors.initials: M
authors.lastname: Huang
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods*; D002233:Carbocysteine / Q000097:blood*; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D002233:Carbocysteine