FORMULATION AND EVALUATION OF MODIFIED RELEASE TRI-LAYERED TABLET USING A FIXED DOSE COMBINATION OF METFORMIN HCL AND VILDAGLIPTIN

The aim of present investigation is to formulate the tri-layered tablet of an Anti-Hyperglycaemic drug comprising Metformin HCl as sustained release layer and Vildagliptin as an immediate release layer in a fixed dose combination along with a fast dissolving intermediate layer or barrier layer in between the two layers just like a sandwich. Vildagliptin is well-known for its instability in presence of Metformin HCl. Hence, Vildagliptin degrades in formulation of single unit dosage form. The in vitro release layer of Metformin HCl was prepared using combination of sustained release polymer HPMC K100M & HPMC K4M and binder used in formulation is Povidone K90 which was prolonged up to 10 - 12 hours. The In-vitro release of Vildagliptin is rapid from tablet and showed highest drug release of more than 90% in 30 Minutes. Final formulation was tested for accelerated stability study. Intermediate barrier layer was optimised using Lactose Monohydrate and Microcrystalline cellulose as a diluents and Croscarmellose sodium as a disintegrant. The disintegration time of tablet into two halves for final formulation was 51 seconds. Combination of lactose monohydrate and microcrystalline cellulose as well as thickness of the intermediate layer was found important to achieve quick disintegration.