Analytical Method Development and Validation for the Simultaneous Estimation of Gabapentin and Nortriptyline by RP-HPLC method

Abstract

In RP-HPLC method, the conditions were optimized to obtain an adequate separation of eluted compounds. Initially, various mobile phase compositions were tried, to separate title ingredients. Mobile phase and flow rate selection was based on peak parameters (height, tailing, theoretical plates, capacity or symmetry factor), run time and resolution. The mobile phase containing mixture of Phophate buffer solution: Methanol (65:35v/v, pH 4) with a flow rate of 1.0 ml/min is quite robust. The optimum wavelength for detection was 260 nm at which better detector response for both the drugs was obtained. The retention times for Gabapentin and Nortriptyline was found to be 2.113 min and 3.560 min, respectively. To ascertain its effectiveness, system suitability tests were carried out on freshly prepared stock solutions. The calibration was linear in concentration range of 5 to 25μg/ ml and 20 to 100μg/ml, with regression 0.9979 and 0.9999, Gabapentin and Nortriptyline respectively. The low values of % R.S.D indicate the method is precise and accurate. The mean recoveries were found above 99.3 % for both the drugs.