Pravastatin sodium (5 g) was dissolved in a 1:1 mixture of ethanol:water (5 ml). The pH was raised to 8.5 by addition of 2M sodium hydroxide in water (1.2 ml) and the solution was heated to 50° C. Acetonitrile (90 ml) was added to the mixture and then the mixture was stirred at elevated temperature for one hour. The mixture was allowed to cool to 20-25° C. (“ambient temperature”), was held at ambient temperature for two hours and then cooled to 5° C. and maintained at 5° C. for 12 hours, whereupon pravastatin sodium crystallized. The crystals were then isolated by filtration and washed with acetonitrile (2×10 ml) and dried under vacuum at 50° C. X-ray diffraction analysis revealed the presence of Form A. Pravastatin Form A was obtained in 92% yield.
