Simultaneous Determination Of Metformin And Glibenclamide In Human Urine By The On-line Coupling Of Solid-phase Extraction And Capillary Electrophoresis

Metformin(MET)and Glibenclamide(GLB)are oral hypoglycemic drugs prescribed most commonly for the treatment of type 2 diabetes.The co-administration of MET and GLB provides better glycemic control than the monotherapy with either of them.However,a series of side effects can be caused such as hypoglycemia and lactic acidosis in an improper dosage.Therefore,it is important to monitor their concentrations in body fluids.Such monitoring is also necessary for pharmacokinetics and bioequivalence studies.Owing to the greater differences in terms of the intrinsic polarity,simultaneously determination of them will face greater difficulties.The previous studies shown that the concentrations of MET and GLB in body fluid after administration of its therapeutic doses are typically at the levels of nanograms per milliliter,it will be another challenge to determine the two drugs.A new method for the simultaneous determination of MET and GLB in human urine has been developed on a homemade online SPE-CE-UV setup.In comparison with the other systems reported previously,the present online system offers the merits of high automation and ease of operation.In addition,it can exactly transfer a distinct volumetric part of SPE elution to CE under the control of a computer with the delay time set at the best value.The sensitivity of the method was improved by ion pair solid phase extraction(IPSPE),which overcomes the difficulty of simultaneous enrichment of two drugs.The influence of experimental parameters on enrichment and separation was investigated in this study.After optimizing the operating conditions of the system,the proposed method was evaluated.The preconcentration factors and plate numbers obtained on the system are separately comparable to those obtained using the independent SPE and CE parts,indicating that the method doesn’t degrade the SPE and CE efficiencies.The obtained results for the urine samples spiked with MET and GLB at three concentrations(50μg/mL,200μg/mL,300μg/mL)levels are 92.3-101.9%,2.4-4.6%(RSD,%,n = 5)for recovery and precision,respectively.The detection limits are 3.4 μg/L and 2.5 μg/L for MET and GLB,respectively.The above experimental results demonstrate that the proposed method is accurate,reproducible,sensitive and applicable for the analysis of MET and GLB in urine.