Formulation and In vitro Evaluation of Immediate Release Bilayer Tablets of Telmisartan and Amlodipine Besylate

The main objective of this combination therapy is to develop a stable formulation of antihypertensive drugs of telmisartan and amlodipine besylate as an immediate release bilayer tablet and evaluate their precompression and post-compression parameters. The FT-IR studies were also conducted and were found to have no interaction between drug and the excipients. The formulation of the developed work was initiated with wet granulation method for both the drugs. Microcrystalline cellulose pH102 and dibasic calcium phosphate were used as diluents. Starch paste was used as the binder. The croscarmellose sodium (CCS) was used as the super disintegrant. Magnesium stearate used as lubricant. The prepared granules were compressed by a double-rotary compression machine. In vitro dissolution was carried out using USP dissolution apparatus type 2 (paddle) by using HPLC method. The optimized formulation F-7 had 98.13% of drug release for telmisartan layer and 96.38% drug release for amlodipine besylate layer. The stability studies for optimized batch were carried out at 30 and 60 days and were found to be stable. The results suggest the feasibility of developing bilayer tablets with two drugs telmisartan and amlodipine besylate for the convenience of patients with severe hypertension, especially when monotherapy fails to control the blood pressure.