Validated Stability Indicating RP-HPLC DAD Method for Simultaneous Determination of Amitriptyline Hydrochloride and Pregabalin in Presence of Stress degradation products in tablet dosage form

High Performance liquid chromatography (HPLC) is an integral analytical tool in assessing drug product stability. HPLC methods should be able to separate, detect, and quantify the various drug-related degradants that can form on storage or manufacturing, plus detect any drug-related impurities that may be introduced during synthesis. A simple, economic, selective, precise, accurate and stability indicating RP-HPLC (Reversed phase–HPLC) method was developed and validated for analysis of Amitriptyline Hydrochloride (AMI) and Pregabalin (PGB) in the formulation. Reversed-phase chromatography was performed on a C18 column with buffer (potassium dihydrogen phosphate) pH 4.0 and acetonitrile, (40:60 %v/v), as mobile phase at a flow rate of 1 mL/min. The detection was performed at 230 nm (nanometer) and sharp peaks were obtained for PGB and AMI at retention time of 4.4 and 9.6 min, respectively. The detection limits were found to be 3.00 µg/mL and 0.59 µg/mL and quantification limits were found to be 9.11 µg/mL and 1.79µg/ml for Pregabalin and amitriptyline hydrochloride, respectively. The method was validated for accuracy, precision, reproducibility, specificity, robustness and detection and quantification limits, in accordance with ICH (international council of hormonization) guideline. Stress study was performed on Pregabalin and amitriptyline hydrochloride and it was found that these degraded sufficiently in all applied chemical and physical conditions. Thus, the developed RP-HPLC method was found to be suitable for the determination of both the drugs as well as stability samples of tablets containing various excipients.