title: LC-tandem mass spectrometry method for the simultaneous determination of metformin and sitagliptin in human plasma after ion-pair solid phase extraction.
abstract: A reversed-phase liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) method was established for simultaneous determination of two oral hypoglycemic drugs metformin (MET) and sitagliptin (STG) in human plasma. The analytes were extracted from 50μL human plasma by ion-pair solid phase extraction using sodium lauryl sulphate on Phenomenex Strata-X (30mg/1mL) cartridges. The chromatographic separation was accomplished on XSelect HSS CN (150×4.6mm, 5μm) column using mobile phase consisting of methanol-8.0mM ammonium formate in water, pH 4.5 (80:20, v/v) under isocratic condition. Tandem MS detection was performed on a triple quadrupole spectrometer equipped with an electrospray ionization source, operated in the positive mode. Multiple reaction monitoring (MRM) was used to quantify the analytes following transitions, m/z 130.1→60.1 and m/z 408.3→235.1 for MET and STG respectively. The method displayed acceptable linearity in the concentration range of 4.00-3200ng/mL for MET and 1.00-800ng/mL for STG. The intra-batch and inter-batch precisions were ≤5.1% and accuracy ranged from 96.5 to 103.3% for both the drugs. The mean recovery of MET and STG obtained from spiked plasma samples was 82.5% and 90.4% respectively with minimal matrix interference. Both the drugs were found to be stable under all mandatory storage conditions. The validated method was successfully applied to a clinical pharmacokinetic study for a fixed-dose tablet formulation containing 500mg MET and 50mg STG in 16 healthy volunteers.
authors.affiliation: Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad- 380009, India.
authors.forename: Priyanka A
authors.initials: PA
authors.lastname: Shah
authors.affiliation: Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad- 380009, India.
authors.forename: Jaivik V
authors.initials: JV
authors.lastname: Shah
authors.affiliation: Department of Chemistry, St. Xavier's College, Navrangpura, Ahmedabad- 380009, India.
authors.forename: Mallika
authors.initials: M
authors.lastname: Sanyal
authors.affiliation: Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad- 380009, India. Electronic address: pranav_shrivastav@yahoo.com.
authors.forename: Pranav S
authors.initials: PS
authors.lastname: Shrivastav
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D006801:Humans; D007004:Hypoglycemic Agents / Q000032:analysis / Q000097:blood*; D008687:Metformin / Q000032:analysis / Q000097:blood*; D000068900:Sitagliptin Phosphate / Q000032:analysis / Q000097:blood*; D052616:Solid Phase Extraction / Q000379:methods*; D013810:Therapeutic Equivalency
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin; D000068900:Sitagliptin Phosphate
keywords: Bioequivalence study; Human plasma; Ion-pair solid phase extraction; LC–MS/MS; Metformin; Sitagliptin