title: Quantitative determination of metformin, glyburide and its metabolites in plasma and urine of pregnant patients by LC-MS/MS.
abstract: This report describes the development and validation of an LC-MS/MS method for the quantitative determination of glyburide (GLB), its five metabolites (M1, M2a, M2b, M3 and M4) and metformin (MET) in plasma and urine of pregnant patients under treatment with a combination of the two medications. The extraction recovery of the analytes from plasma samples was 87-99%, and that from urine samples was 85-95%. The differences in retention times among the analytes and the wide range of the concentrations of the medications and their metabolites in plasma and urine patient samples required the development of three LC methods. The lower limit of quantitation (LLOQ) of the analytes in plasma samples was as follows: GLB, 1.02 ng/mL; its five metabolites, 0.100-0.113 ng/mL; and MET, 4.95 ng/mL. The LLOQ in urine samples was 0.0594 ng/mL for GLB, 0.984-1.02 ng/mL for its five metabolites and 30.0 µg/mL for MET. The relative deviation of this method was <14% for intra-day and inter-day assays in plasma and urine samples, and the accuracy was 86-114% in plasma, and 94-105% in urine. The method described in this report was successfully utilized for determining the concentrations of the two medications in patient plasma and urine.
authors.affiliation: Maternal-Fetal Pharmacology and Bio-development Laboratories, Department of Obstetrics and Gynecology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX, 77555-0587, USA.
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Wang
authors.forename: Daria I
authors.initials: DI
authors.lastname: Vernikovskaya
authors.forename: Valentina M
authors.initials: VM
authors.lastname: Fokina
authors.forename: Tatiana N
authors.initials: TN
authors.lastname: Nanovskaya
authors.forename: Gary D V
authors.initials: GD
authors.lastname: Hankins
authors.forename: Mahmoud S
authors.initials: MS
authors.lastname: Ahmed
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D016640:Diabetes, Gestational / Q000097:blood / Q000188:drug therapy*; D005260:Female; D005905:Glyburide / Q000097:blood* / Q000627:therapeutic use / Q000652:urine*; D006801:Humans; D007004:Hypoglycemic Agents / Q000097:blood* / Q000627:therapeutic use / Q000652:urine*; D008687:Metformin / Q000097:blood* / Q000627:therapeutic use / Q000652:urine*; D011247:Pregnancy; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin; D005905:Glyburide
keywords: LC-MS/MS; gestational diabetes mellitus; glyburide; metabolites; metformin