Formulation and Evaluation of Multiparticulate Drug Delivery System of Valsartan

The objective of the present study was to prepare valsartan pellets and to coat with pH-responsive polymers for chronomodulated delivery. The pellets containing valsartan, Avicel and lactose were prepared by extruder spheronizer using different binders HPMC E-5 and PVP K-30. The optimized pellets were coated with different weight ratios of pH-responsive polymers Eudragit^® S100 or RS. The pellets were evaluated for physical properties namely, surface appearance, size analysis, content uniformity, micromeritic properties, friability, infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, Feret diameter, aspect ratio, stability study and in vitro release studies. Based on in vitro release studies and SEM analysis, pellets containing 2.5% PVP K-30 were found to be optimized for coating. The drug was compatible when mixed with excipients, which was confirmed by IR spectroscopy and differential scanning calorimetry. Pellets showed good micromeritic properties. Further, in vitro release study of coated pellets revealed optimum lag-time (6±0.25 h) before drug release and Eudragit^® S100 with 25% weight gain was optimized. There was no significant change in the drug content and release profile of the pellets stored under accelerated conditions. Thus the multiparticulate delivery system of valsartan found to be suitable as potential chronomodulated drug delivery system to treat early morning surge in hypertensive patients.