Formulation and in vitro evaluation of bilayer tablets of nebivolol hydrochloride and nateglinide for the treatment of diabetes and hypertension.

Diabetes mellitus (DM) and hypertension are two common diseases that often coexist. The most common cause of death in the diabetic patient is heart disease. In the present investigation we combine Nebivolol and Nateglinide for better patient compliance. IR layer was formulated using various superdisintegrants like Crospovidone, Croscarmellose sodium, and sodium starch glycolate and SR layer was formulated using polymers and gums like HPMC E15, ethyl cellulose, Gaur gum, and Xanthan gum. The disintegration and dissolution study of both layers showed that inclusion of surfactant (sodium lauryl sulphate) to the tablet formulation (IR) and dissolution medium (SR) enhanced the release of drugs from both layers. Kinetic studies of optimized IR layer (NBL8) and SR layer (N9) showed good linearity with regression coefficient of 0.9714 (Higuchi model) and 0.9931 (zero order kinetics), respectively. The above results reveal that the optimized IR layer of Nebivolol (NBL8) and SR layer of Nateglinide (N9) might be suitable for the treatment of diabetes and hypertension by sequential release of the two drugs in a bilayer tablet. IR-immediate release, SR-sustain release, NBL8-Nebivolol 8, N9-Nateglinide 9.