The present study was designed to conduct forced degradation study and validate a RP-HPLC method which is capable of estimating the content and release of Levodopa, Carbidopa and Entacapone simultaneously in combined dosage form.
Methods: The developed RP-HPLC method was challenged for all method validation parameters as guided by ICH: Q2(R1) like specificity, linearity, range, accuracy, precision, robustness, system suitability. For determining whether the analytical method is stability indicating, the analytes were exposed under various stress conditions like light, heat, oxidation, hydrolysis to conduct forced degradation study.
Results: The method was found linear in a range of 32 -320, 8 -80 and 32 -320 µg/ml with correlation coefficient of 0.9999, 0.9999 and 0.9995 respectively for Levodopa, Carbidopa and Entacapone. LOD and LOQ of Levodopa, Carbidopa and Entacapone was found to be 2.10, 1.34 & 9.56 µg/ml and 6.35, 4.05 & 28.96 µg/ml respectively. Method precision was found to be within the % RSD ≤ 1. Average accuracy of the method was found to be 100.33, 99.79, 100.12% for Levodopa, Carbidopa and Entacapone respectively. The method was shown to be selective and robust. The method was successfully validated to be stability indicating. Finally, the method was successfully applied for simultaneous estimation of content and release of Levodopa, Carbidopa and Entacapone in commercial available brand of combined dosage form.
Conclusion: The method is found to be simple, economical, specific, precise, accurate, sensitive, robust, rapid & stability indicating and can be transferred to laboratory for routine analysis of the combined dosage form.