Author : Jignesh Shah, Vrunjan Shah, Deepika Koul, Aryan Gupta, Akash Goswami, Amit Patel, Dharmesh Shah, Kaushik Shah
Dissolution profiles of carbamazepine innovator formulation were evaluated and matched with the test formulation in multiple dissolution medium at various pH. Innovator formulation – Tegretol LP 400 was selected as a reference product. Different batches of innovator and test formulation of 400mg were selected for experiments. During development, the test formulation was formulated with respect to the dissolution profile of Tegretol LP 400 in defined medium – water. After achieving the matched dissolution profile in main medium - water, same test formulation was matched with innovator formulation in various pH medium. The similarity factor (f2) for test and reference product was obtained more than 50 for medium - water, acetate buffer pH 4.5 and phosphate buffer 6.8. During acidic medium at pH 1.2, the innovator formulation represented the typical behavior in dissolution and due to that high variability was observed in the results of intra-run. Same behavior of drug release was also observed for the repeated experiments as well as for other batch of innovator and even in the final test formulation. Hence, to prevent the high variability, surfactant was used for the dissolution in pH 1.2 medium. After various optimization experiments, the minimum optimum concentration of surfactant was achieved and the results of %RSD was found within acceptance criteria for all the formulations. The similarity factor (f2) of 12 units of test and reference product was found above 50. The results were also accepted for the other batch of innovator formulation and during the repetitive experiments.