Most of the new chemical entity suffers from low bioavailability due to their low aqueous solubility and dissolution. Many approaches have been used like micronization, solubilization, complexation with polymer, salt formation, use of prodrug, addition of surfactant, solid dispersions, etc. But all these methods suffer from limitations like size reduction by micronization, form surface charges which show poor flow property.1) Amorphous system exhibits significant solubility benefits, due to excess thermodynamic properties and lower energetic barrier than its crystalline form.2) The major reason for limited solubility benefit from amorphous system is their devitrification, on exposure to primary aqueous dissolution medium. This limited solubility can be overcome by further increases in solubility by preparing solid dispersions (SD) with polymer having high glass transition temperature (Tg) value like hydroxypropyl methylcellulose (HPMC), polyvinyl pyrrolidone (PVP).3) SD increases the solubility by slowing devitrification, and increased wettability due to hydrophilic nature.4) Solid dispersion is useful method to disperse drugs in the molecular state in a carrier matrix. 5,6) Various methods have been reported for preparation of solid dispersion like physical mixture, kneading method, spray drying, solvent wetting, and modified solvent evaporation method. 7) Most of these methods are amenable only to research laboratory set up, with the exception of spray drying, which can be scaledup industrially. 8) Solid dispersions by spray drying technique has been reported for wide variety of poorly aqueous soluble drug like glibenclamide, 9) curcumin, 10) albendazole, 11) tolbutamide, 12) loperamide. [4,4]non-1-en-4-one antagonizes angiotensin II by blocking AT 1 receptors is indicated for treatment of hypertension.14) It belongs to class II drug according to biopharmaceutical classification system (BCS) i.e. low solubility and high permeability. According to BCS drug substance is considered to be highly soluble when highest dose of drug dissolve in less than 250 ml of water. It is considered to be highly permeable when the extent of absorption in human is more than 90% of an administered dose. Although it has excellent oral bioavailability (60-80%), but theoretically IBS exhibits solubility limited bioavailability and it would be advantageous to increase the solubility of such molecule.15) Solubility of IBS was found to be increased after complexation with polymer like b-cyclodextrin. 16)In this study solid dispersions of IBS were prepared by spray drying technique using low viscosity grade of HPMC E5 LV having the high Tg value in order to enhance its solubility, dissolution rate and bioavailability. Spray drying technique has advantages like generation of amorphous system and formation of solid dispersions simultaneously. The physical properties of the prepared solid dispersions were characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), powder X-ray diffractometry (PXRD), Fourier ...