Development of Simple, Facile Spectrophotometric Method for Determination of Metformin Hydrochloride in Aqueous Medium

Metformin hydrochloride, anti-hyperglycemic drug, is one of the most widely used medications for treatment of diabetes worldwide. However, the recent reports confirmed the presence of metformin in waste water treatment plants and aqueous bodies and the drug is listed as pharmaceutical pollutant. The present study reports the development of simple, rapid and selective spectrophotometric method for the detection and determination of metformin in pure and tablet dosage form aqueous medium.The method is devised on the basis of complexation of metformin with Cu2+ ions in basic medium and recording the absorbance at 647.5 nm. The various parameters such as concentrations of Cu2+ ions, ammonia and metformin affecting the complexation process and corresponding to region of highest sensitivity were optimized. The method was also optimized on the basis of time study and pH of metformin solution. Metal: Ligand ratio of the formed complex was determined from the Job’s method of continuous variation and is found to be 1:2. The detection limit and correlation coefficient(r) of the devised method are 5-25 μg/mL and 0.9922 μg/mL respectively. The method was also validated for determination of drug Glycomet GP-1 tablets with accuracy +-0.003. Further, Solid Cu2+-Metformin complex was also
synthesized and characterized by FTIR and NMR spectroscopic data. The complexation method offers the accurate, rapid, selective and economical, determination of anti-diabetic drug in aqueous medium and can be employed for estimation of metformin in wastewaters/effluents.