Oral bioavailability of irbesartan (IBS) is only 60% due to its poor aqueous solubility and dissolution rate. The present research work was aimed for improvement of dissolution of IBS by melt dispersion technique which is supposed to improve oral bioavailability. Solid dispersions of IBS were prepared using polymeric additives (polyvinylpyrrolidone, copovidone, polyethylene glycol and poloxamer) in different ratios. Quantitative solubility of selected formulations were evaluated after a trial of physical solubility study of all the formulations. Formulation A [IBS/PVP (1:1) + poloxamer 10%] and formulation B [IBS/PVP (1:2) + poloxamer 5%] were taken for micronization by jet milling (Cadmach, Ahmedabad, india). Formulation A and B have been characterised by instrumental study such as particle size analysis (Sympatech particle size laser analyser, GmbH, Germany); XRD (Mettler Toledo, USA); DSC (Mettler Toledo, USA). Formulation A and B have been tableted (each tablet contains 150mg IBS) using Micro Crystalline Cellulose (MCC 102), as major filler by direct compression applying 100-120 N pressure. Solubility of A and B have been improved to 4.6 (.0055mg/ml) times and 3.8 (0.046mg/ml) times respectively compared to pure drug (0.012mg/mL). IBS dissolution of tablet A has been improved to 71.76% in SGF (0.1N HCl). Micronized particle size of A (X90:103μ) and B (X90:69μ), and amorphization of drug in Solid dispersions (decreased intensity of XRD and is appearance of endothermic peak of crystalline drug) have brought about improved dissolution.
