Innovative Analytical Method Development and Validation for Metformin Using Simulated Salivary Fluid: A Preformulation Approach

The current study aims to evaluate and assess the physiochemical characteristics of metformin hydrochloride, which is commonly used to treat type II diabetes. This study also focuses on the method development and validation of metformin hydrochloride by the UV-spectrophotometric method. The validation procedure adhered to the protocols specified by the ICH guidelines. The spectroscopic studies were done using simulated phosphate salivary fluid as a solvent, which mimics the physiological fluid in the human oral cavity. The drug was evaluated for its organoleptic assessment, solubility, pH, FTIR spectroscopy, partition coefficient, melting point, moisture content, and flow properties. The preformulation characteristics were thoroughly assessed and evaluated with the ranges specified in the monograph, and it was found to be within the limits. The absorption maxima for the drug using a simulated salivary fluid of pH 6.8 were found to be 233 nm, and the calibration curve for the metformin exhibited a linearity range of 1–9 μg/mL (r² = 0.998). The recovery studies were done at three different concentration levels and were found to be in the range of 97–98.8%. This study evaluates how the developed method meets its criteria for specificity, linearity, and accuracy, within the predefined acceptance limits. Thus, a simple, accurate, and economical method is developed and validated along with the preformulation characteristics, which expands its utility in the formulation of the drug.