Formulation and Evaluation of Mucoadhesive Microspheres of Valsartan

The objective of the present study is to reduce dosing frequency and improve patient compliance by designing and systematically evaluating mucoadhesive microspheres of valsartan. Frequent administration and variable low bioavailability (20-25%) after oral administration are problems of conventional dosage forms of valsartan. This can be attenuated by designing it in form of mucoadhesive microspheres which would prolong the residence time at the absorption site to facilitate intimate contact with absorption surface and thereby improve and enhance bioavailability.Valsartan microspheres were formulated by Emulsion Solvent Evaporation technique using polymers i.e. Xanthum Gum, Tragacanth, Carbopol 940 and HPMC K4M. All the formulations (F1-F12) were subjected to Percentage yield, Entrapment efficiency, Particle size analysis, Loose surface crystallography, Swelling index, Mucoadhesion test, In-vitro drug release studies and Scanning electron microscopy. FTIR data indicates that there was no drug interaction between drug and polymers used. Scanning electron microscopy indicated that microspheres (289±2.28μm-399±3.12μm) were spherical in shape and drug remained dispersed in polymer matrix. Among all formulations, the formulation F12 displayed better result whose Percentage yield (98.6%), Entrapment efficiency (88.9±0.17%), Swelling index (78.8±1.84mg) and In-vitro drug release was found to be 95±0.24% after 12 hours. The formulation F12 is following zero-order kinetics with non-fickian diffusion mechanism. Based on all the above evaluation parameters it was concluded that the formulation F12 was found to be the best formulation among all the formulations and can be used in the treatment of Hypertension.