after 4 days of stirring at ambient temperature the solids were isolated by vacuum filtration using a buchner funnel fitted with a paper filter 2 whatman the solids were rinsed with acetonitrile 75 ml and placed in a 25 u00b0 c oven under nitrogen to dry for two days to afford atorvastatin olamine the piperazine salt of atorvastatin was synthesized by preparing a stock solution of the free acid of atorvastatin u s pat no 5 273 995 in isopropyl alcohol 2 577 g in 50 ml of ipa a solution of piperazine was prepared by dissolving 14 4 mg 1 0 equivalents in isopropyl alcohol 1 ml the stock solution of atorvastatin free acid 1 85 ml was added to the counterion solution with stirring after 7 days of stirring at ambient temperature the solids were isolated by vacuum filtration using a 0 45 u03bcm nylon 66 membrane filter the solids were rinsed with isopropyl alcohol and air dried at ambient conditions to afford atorvastatin piperazine the sodium salt of atorvastatin was synthesized by preparing a stock solution of the free acid of atorvastatin u s pat no 5 273 995 in acetonitrile 0 634 g in 25 ml of acn a solution was prepared by dissolving 2 67 mg of sodium hydroxide 1 0 equivalents in 0 5 ml of acetonitrile and 0 05 ml of water the stock solution of atorvastatin free acid 1 55 ml was added to the counterion solution.