Process for purifying pravastatin sodium from a fermentation broth

A process for purifying pravastatin sodium comprising the steps of: a. clarifying a fermentation broth containing pravastatin sodium to obtain a clear solution; and adjusting the clear solution to be basic having pH value ranging from pH 10.about.13; b. adsorbing the pravastatin sodium with non-ionic resin; eluting the pravastatin sodium by water-soluble organic solvent; and forming a concentrate of pravastatin sodium; c. treating the concentrate with water-soluble anti-solvent or inorganic salt to form a precipitate of pravastatin sodium; and d. recrystallizing the precipitate for making pravastatin sodium crystal with high purity and high yield.

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We claim:

1. A process for stably purifying pravastatin sodium comprising the steps of: a. clarifying a fermentation broth containing pravastatin sodium by a step selected from centrifugation andfiltration to obtain a clear solution containing the pravastatin sodium; and adjusting the clear solution to be basic having pH value ranging from pH 10.about.13; b. adsorbing the pravastatin sodium with non-ionic resin which is then washed with water; eluting the pravastatin sodium as adsorbed on the resin by water-soluble organic solvent, which is selected from: methanol, acetone and a mixture of methanol and acetone, to obtain pravastatin sodium fraction; and concentrating the fraction to bepravastatin sodium concentrate; c. treating the concentrate to form a precipitate of pravastatin sodium; and d. recrystallizing the precipitate for making pravastatin sodium crystal with high purity and high yield.

2. A process according to claim 1, wherein the treating of said concentrate for forming a precipitate of pravastatin sodium in step (c) comprising the addition of water-soluble anti-solvent into said concentrate.

3. A process according to claim 2, wherein said water-soluble anti-solvent selected from: ethanol, n-propanol, isopropanol, acetone and the mixture thereof.

4. A process according to claim 1, wherein the treating of said concentrate for forming a precipitate of pravastatin sodium in step (c) comprising the addition of inorganic salt for salting out the pravastatin sodium precipitate.

5. A process according to claim 4, wherein said inorganic salt is selected form: ammonium sulfate, ammonium chloride, sodium sulfate, sodium chloride and potassium chloride.