title: Ultra-performance hydrophilic interaction LC-MS/MS for the determination of metformin in mouse plasma.
abstract: BACKGROUND
  Ultra-performance (UP) hydrophilic interaction LC (UPHILIC) interfaced with an ESI source and MS/MS was developed for the determination of metformin in mouse plasma samples.
  
  
  METHODS
  Several silica stationary phases under HILIC conditions were adapted to evaluate the retention mechanism profiles of the analyte. The influences of experimental factors such as the compositions of mobile phases on the chromatographic performance and the ionization efficiency of the test compounds in positive ion mode were investigated. The applicability of the proposed UPHILIC-MS/MS approach following a protein precipitation procedure for the quantitative determination of metformin at nanomole levels was examined with respect to assay specificity and linearity.
  
  
  RESULTS
  The analytical results obtained by the described UPHILIC-MS/MS approach were found to be in good agreement with those obtained by an ion-pair UPLC-MS/MS method in terms of assay sample throughput, sensitivity and accuracy.
  
  
  CONCLUSIONS
  The results suggested that it is feasible to convert a reversed-phase UPLC-MS/MS method to a UPHILIC-MS/MS method by simply switching the analytical columns while maintaining the rest of the experimental conditions for polar pharmaceutical analyses with enhanced retention and sensitivity.
authors.affiliation: Schering-Plough Research Institute, 2015 Galloping Hill Road, K-15-3700, Kenilworth, NJ 0703, USA. yunsheng.hsieh@spcorp.com
authors.forename: Yunsheng
authors.initials: Y
authors.lastname: Hsieh
authors.forename: Gerica
authors.initials: G
authors.lastname: Galviz
authors.forename: Joyce J
authors.initials: JJ
authors.lastname: Hwa
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D056148:Chromatography, Reverse-Phase / Q000379:methods*; D008687:Metformin / Q000097:blood*; D051379:Mice; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D008687:Metformin