Stability indicating UV spectrophotometric methods for the determination of nateglinide in pharmaceuticals

Two methods which are simple, rapid and cost-effective are presented for determination of NTG in bulk and tablets using uv-spectrophotometry. Methods are based on measurement of absorbance of drug solution either in 0.1M NaOH at 210 nm (NaOH method) or in 0.1 M HCl at 270nm (HCl method). Beer’s law is obeyed over concentration ranges of 3-54 and 4-72 μg/mL for NaOH method and HCl method, respectively; and corresponding molar absorptivity values are 4.09 ×103 and 3.04 ×103 L/mol/cm. Calculated Sandell sensitivities are 0.0776 and 0.0995 μgcm-2 with NaOH and HCl as diluents, respectively. Limits of detection (LOD) and quantification (LOQ), calculated according to the ICH guidelines are: 0.91 and 2.73μg/mL (NaOH method) and 0.72 and 2.16 μg/mL (HCl method). Intra-day and inter-day accuracy and precision, determined by replicate analyses at three concentration levels, were ≤2% (%RE) and ≤1.63% (%RSD), respectively. Method robustness was assessed by making small changes in the measurement wavelength whereas the ruggedness was tested by inter-analysts and inter-cuvettes variations. Validated methods were applied to the determination of active ingredient in tablets. Drug was subjected to forced degradation via acid and alkali hydrolysis, oxidation, thermolysis and photolysis.