Simultaneous estimation of gabapentin and methylcobalamin in bulk and pharmaceutical dosage form by RP-HPLC

A simple, selective, linear, precise, and accurate RP-HPLC method was developed and validated for the simultaneous estimation of Gabapentin & Methylcobalamin from bulk and formulation. Chromatographic separation was achieved Isocratically on an Inertsil C18 column (150x4.6, 5µ particle size) using a mobile phase Buffer: Acetonitrile in the ratio of 60:40 v/v. The flow rate was 1.0 ml/min, effluents were detected at 264 nm and 10µl of sample was injected. Retention time of Gabapentin & Methylcobalamin was found to be 2.7 and 4.13 min respectively. Linearity of the method was in the concentration range of 25-150 µg for Gabapentin & 0.125-0.750 µg for Methylcobalamin. Percent recoveries obtained for both the drugs were 100.00%. The percentage RSD for precision of the method was found to be less than 2%. The method was validated according to the ICH guidelines. The method developed was successfully applied for the analysis of simultaneous estimation of Gabapentin & Methylcobalamin tablets and was fairly good in comparison with other methods. Keywords: Gabapentin, Methylcobalamin, HPLC.