Spherically agglomerated solid dispersions of valsartan to improve solubility, dissolution rate and micromeritic properties

Abstract

The objective of the present work was to enhance the solubility and dissolution rate of valsartan (VAL) a poorly water soluble antihypertensive, by spherically agglomerated solid dispersions using methanol, water and dichloromethane as good solvent, poor solvent and bridging liquid, respectively. The hydrophilic polymers like polyvinyl pyrrolidone, Hydroxypropyl β-cyclodextrin, Hydroxypropyl methylcellulose were used in agglomeration process. The pure drug (VAL) and its agglomerates with different polymers were characterize by differential scanning calorimetry (DSC), X-ray diffraction (XRD), IR spectroscopic studies and scanning electron microscopy (SEM). The DSC results indicated that decrease in melting enthalpy related to disorder in the crystalline content. XRD studies also showed changes in crystallanity, IR spectroscopy revealed that there were no chemical changes in the recrystallized agglomerates. The spherically agglomerated solid dispersions with different polymers exhibited marked increase in solubility, dissolution rate and micromeritic properties (bulk density, flow property, compactability) compared with VAL. The SEM studies showed that the agglomerates posseeses a good spherical shape. Keywords: Valsartan; Spherical agglomeration; Solid dispersion; Solubility; Dissolution rate; Micromeritic properties.