STUDY ON DISSOLUTION IMPROVEMENT OF ALLOPURINOL BY CO-GRINDING AND FUSION METHOD USING SOLID DISPERSION TECHNIQUE

Abstract

Allopurinol is a commonly used drug in the treatment of chronic gout or hyperuricaemia associated with treatment of diuretic conditions. One of the major problems with the drug is that it is practically insoluble in water, which results in poor bioavailability after oral administration. In the present study, solid dispersions of allopurinol (allo) were prepared by co-grinding method and melting methods to increase its water solubility. Hydrophilic carriers such as polyvinylpyrrolidone, polyethylene glycol 6000 were used in the ratio of 1:1, 1:2 and 1:4 (drug to carrier ratio). The aqueous solubility of allopurinol was favored by the presence of both polymers. These new formulations were characterized in the liquid state by phase solubility studies and in the solid state by UV spectroscopy. Solid state characterizations indicated that allopurinol was present as an amorphous material and entrapped in polymer matrix. In contrast to the very slow dissolution rate of pure allopurinol, the dispersion of the drug in the polymers considerably enhanced the dissolution rate. Solid dispersion prepared with Kollicoat IR showed highest improvement in wettability and dissolution rate of allopurinol. Therefore, the present study showed that kollicoat IR has a significant solubilizing effect on allopurinol

KEYWORDS: Allopurinol, polyethylene glycol 6000, solid dispersions, closed melting method, dissolution enhancement.