Preparation and evaluation of mixture of eudragit and ethylcellulose microparticles loaded with ranolazine for controlled release.

To minimize the unwanted toxic effects of anti-anginal ranolazine by kinetic control of drug release, it was entrapped into gastro-resistant, biodegradable eudragit (EU) and ethyl cellulose (EC) binary blend using phase separation method. Ten formulations were prepared using different polymer blend ratios and solvent. The prepared microparticles were characterized for micromeritic properties, polymer drug compatibility by Fourier Transform Infrared Spectroscopy (FT-IR) and Differential Scannibg Calorimetry (DSC), and surface morphology by Scanning Electron Micrography (SEM). The yield of microparticles was up to 90% and more than 98% of the isolated microparticles are having volume mean diameter of 285 μm. The obtained angle of repose, percentage Carr's index and tapped density values were within the limits indicating good flow properties. The surface morphology revealed that particles were free-flowing, spherical, with minute pores and invert dents on the surface. The prepared microparticles were evaluated for percentage yield, encapsulation efficiency and in vitro release studies. FT-IR and DSC studies showed no chemical interaction between the drug and used polymers The in vitro drug release studies were carried out using pH 1.2 acid buffer and pH 7.4 phosphate buffer. EU acts as an excellent pH-dependent binder and helps to release the drug in the intestine. The drug release kinetics followed different transport mechanisms. Increasing the weight fractions of EU and decreased EC helps to control the drug release from the particles. From the differential (f(1)) and similarity factor (f(2)), Formulation F5 was the formulation most similar to the commercially available oral formulation as reference standard. The drug release performance was greatly affected by the materials used in microparticle preparations, which allow absorption in the intestinal tract.