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 λmax 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.