Objective: The current study involves the fabrication of oral bilayer matrix designs of a combination of two drugs, metoprolol succinate and atorvastatin calcium, the optimization of their in vitro release and characterization using the design expert software. Metoprolol succinate, a β1- selective adrenergic receptor blocking agent, is used in the management of hypertension has a half-life of approximately 4–5 h; thus, there is the need to use extended-release formulation for prolonged action. Atorvastatin is a hydroxymethylglutaryl-coenzyme A reductase inhibitor, an antilipidemic, used to lower blood cholesterol. The rationale for this fixed-dose combination is to coadminister two drugs acting by different mechanisms of action together, reduce dosing frequency, and increase patient compliance.Methods: A 32 factorial design was selected to analyze the effect of critical factors, polymer concentration of Kollidon sustained release (SR), and Eudragit RS and their interaction on the in vitro release of the SR part containing metoprolol succinate. The drug release at 2 h (Q2), 8 h (Q8), and 20 h (Q20) was taken as responses. The blends of both layers were prepared, evaluated for precompression characteristics, and compressed by direct compression. The compressed bilayer tablets were evaluated for their hardness, weight variation, friability, content uniformity, diameter, and in vitro release.Result and Conclusion: The release profile indicates Higuchi’s kinetics. Contour and surface response plots show significant interaction among the formulation variables. Formulation MS06 containing 70 mg Kollidon SR and 10 mg Eurdragit RS was found to be the optimized formulation, controlling the drug release for a 24 h period.

Objective: The current study aims at fabrication of an oral bilayer matrix tablet of bosentan monohydrate and sildenafil citrate; the optimisation of their in vitro release and characterization, thereby reducing the side effects associated with bosentan, reducing dosing frequency and increasing patient compliance in the management of pulmonary arterial hypertension. Methods: Methocel K4M Premium DC2, a directly compressible HPMC grade was used as the sustained release polymer. Pregelatinised starch is used as a diluent and release modifier and sodium lauryl sulphate (SLS) as a solubiliser. The blends of both layers were prepared, evaluated for precompression characteristics and compressed by direct compression. The compressed bilayer tablets were evaluated for their hardness, weight variation, friability, content uniformity and swelling index. The principle objective was to assess the influence of the above variables on in vitro drug release of Bosentan using a 23 factorial design. Responses are measured as drug release at 2h (Q2), 6h (Q6) and 10h (Q10). Results: HPMC and pregelatinized starch form a synergistic gel thereby controlling drug release of bosentan for a 12 hour period. Batch BS09 consisting of 40 mg HPMC, 30 mg Pregeletinized starch and 5 mg SLS showed adequate controlled release for a 12 h period. Immediate release layer of sildenafil citrate showed optimum drug release of 102.96% within 30 min. Conclusion: Bilayer tablet of bosentan and sildenafil is an ideal combination for patients failing monotherapy in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) means high blood pressure in the lungs caused by obstruction in the small arteries of the lungs.The current study involves the fabrication of oral matrix sustained release tablet of bosentan monohydrate, a dual endothelin receptor antagonist, the optimisation of its in vitro release and characterisation. Methocel K4M PremiumDC2, a directly compressible HPMC grade, has been used as the sustained release polymer. Pregelatinised starch is used as a diluent and release modifier and sodium lauryl sulphate as a solubiliser. The influence of the above variables on drug release is measured using a 23 factorial design using design expert software. Surface response plots show significant interaction among the formulation variables, thus aiding in optimization of bilayer tablet.