monohydrate 25 g 0 094 mol and aqueous ethanol the mixture was heated to boiling with stirring the aqueous ethanolic sodium hydroxide was added dropwise to the suspension of alendronic acid monohydrate in aqueous ethanol for 3 hours at reflux with vigorously stirring then the mixture was stirred at reflux for additional 15 hours the mixture was cooled to room temperature with stirring the solid was filtered washed with absolute ethanol then with absolute ethyl ether and dried overnight in a vacuum oven 10 15 mm hg 40 50 u00b0 c to give 26 2 g of alendronate sodium having crystalline form g a suspension of alendronate sodium trihydrate 1 0 g 3 08 mmol in aqueous ethanol 10 ml of ethanol 1 9 ml of water was boiled at reflux with stirring for 15 hrs after cooling to ambient temperature the solid was filtered washed with absolute ethanol and ether and dried overnight in a vacuum oven 10 15 mm hg ambient temperature to give 0 9 g of alendronate sodium containing crystal form g absolute ethanol 50 ml and water 6 7 ml 20 u00d7 0 019 mol were mixed sodium hydroxide 0 76 g assay 99 0 019 mol was dissolved in 8 5 ml of this aqueous ethanol the remaining aqueous ethanol was used to prepare a suspension of alendronic acid monohydrate a 250 ml flask was fitted with a mechanical stirrer a thermometer a dropping funnel and a reflux condenser the flask was charged with alendronic acid monohydrate 5 g 0 019 mol and aqueous ethanol the aqueous ethanolic sodium hydroxide was.