Derivative Spectrophotometric and Isocratic High Performance Liquid Chromatographic Methods for Simultaneous Determination of Repaglinide and Metformin Hydrochloride in Pharmaceutical Preparations

Abstract

In this study, a derivative spectrophotometric method and one HPLC method were developed and validated for analysis of anti-diabetic drugs, repaglinide (RPG) and metformine hydrochloride (MTF) in tablets. The spectrophotometric methods were based on zero-crossing first-derivative and fourth-derivative spectrophotometric method for simultaneous analysis of RPG (308 nm) and MTF (267 nm), respectively. Linear relationship between the absorbance at λ max and the drug concentration was found to be in the ranges of 5.0 - 50.0 μg · mL -1 for both RPG and MTF. The quantification limits for RPG and MTF were found to be 0.568 and 1.156 μg · mL -1 , respectively. The detection limits were 0.170 and 0.347 μg · mL -1 for RPG and MTF, respectively. The second method is a rapid stability-indicating isocratic HPLC method developed for the determination of RPG and MTF. A linear response was observed within the concentration range of 5.0 - 50.0 μg · mL -1 for both RPG and MTF. The quantification limits for RPG and MTF were found to be 1.821 and 1.653 μg · mL -1 , respectively. The detection limits were 0.601 and 0.545 μg · mL -1 for RPG and MTF, respectively. The proposed methods were successfully applied to the tablet analysis with good accuracy and precision.