反应详情

Pantoprazole sodium Form II can be prepared by forming a solution of pantoprazole and excess sodium hydroxide in acetone and crystallizing Form II from the solution. Preferably, pantoprazole is added as the free base, though the sodium salt may be used. Excess sodium hydroxide is conveniently added as a concentrated aqueous NaOH solution. Sodium hydroxide should be added in an amount of from about 1 to about 2 molar equivalents with respect to pantoprazole. In a particularly preferred procedure, pantoprazole is dissolved in about 3-6 volumes of acetone. The solution is cooled to about 0° C. Then, the concentrated NaOH solution is added. Crystallization of the novel form of pantoprazole sodium is substantially complete within about 1-5 hours. The crystals can then be separated from the acetone by conventional means, such as by filtering or decanting and they may be washed, preferably with acetone.