Quantitative determination of Epalrestat by RP-HPLC method

Epalrestat an aldose reductase inhibitor is used in the treatment of diabetic peripheral neuropathy. A simple, sensitive, precise and accurate RP-HPLC method for determination of epalrestat both as a bulk drug and in pharmaceutical formulation has been developed and validated as per the International Conference on Harmonization (ICH) guidelines. Chromatographic separation was achieved using Qualisil C8 column, detection at 294 nm and mixture of methanol: (0.01 mol L^-1) potassium dihydrogen phosphate (75:25 v/v), pH adjusted to 4.5 with ortho-phosphoric acid as mobile phase. A typical retention time for eparlestat was 6.64 ± 0.02 min. Linearity was observed in concentration range of 2 – 12 μg.mL^-1 with coefficient correlation (r^2 = 0.999). The % RSD value for intra-day and inter-day precision was found to be in the range of 0.32 - 0.79 % and 0.12 -1.32 %. The mean % recovery was found to be in the range of 99.47 - 100.30 %. The low values of LOD (0.15 μg) and LOQ (0.46 μg) indicate high sensitivity of the method. The % RSD value for robustness and ruggedness studies was found to be less than 2 %. The amount of drug estimated was found to be in good agreement with label claim. The developed method can routinely be used for analysis ofepalrestat in pharmaceutical formulations.