ABSTRACT
Objective: To investigate the physicochemical equivalence of four brands of commercially available glibenclamidetablets in Nigeria and to develop a validation method using HPLC for the quantitative determination of glibenclamide and its sulfonamide impurity present in thesetablets.Methods: Uniformity of weight, friability tests, hardness/crushing strength, dissolution,anddisintegration tests were carried out on tablets/drug samples of each brand. Theirfunctional groups were determined and compared with pure glibenclamide sample (reference standard) using Fourier Original Research Article Transform Infrared Spectroscopy (FTIR) between a range of 4000cm-1to 400cm-1. High-Performance Liquid Chromatography (HPLC) was used to determine the percentage of glibenclamide and its sulfonamide impurity present in each tablet brand. Results: From the physicochemical evaluation of the four brands ofglibenclamide tablets tested, the brands passed all the British Pharmacopeia specifications,but they all failed the hardness/crushing strength tests and one of the brands failed the assay test requirement for drug content. The developed HPLC method had apercentage recovery between the acceptable limit of 95-105% with percentage relative standard deviation (%RSD) of < 3% while the precision of the method was 0.102%and 0.383% for glibenclamide and its sulfonamide impurity, respectively. The Limit of Detection (LOD)and Limit of Quantification (LOQ)of the developed analytical method for the four brands were 0.075μg/ml and 0.227μg/ml for glibenclamide while that of sulfonamide impurity were0.114μg/ml and 0.345μg/ml,respectively.In addition, the percentage impurity of sulfonamide in all the brands was less than the acceptable limit of 1%.Conclusion: Theresultsfrom thephysicochemical evaluation of the glibenclamide brands justified the need forconstant monitoring of marketed drug products. The results obtained from theHPLC quantification methoddeveloped for this study show that our data is reproducible based on the linearity, precision, and accuracyof data generated forglibenclamide and its sulfonamide impurity inthe four brands of glibenclamide tablets prescribed to DM patients in Nigeria, which were judged to besatisfactoryat the time of this study