Stable Pharmaceutical Compositions Containing Pravastatin

Abstract

Stabilized pharmaceutical preparations containing a drug which is sensitive to a low pH environment, such as pravastatin are disclosed in which pravastatin degradations is prevented with a buffering agent. The basic excipient enhances storage stability.

1 - 22 . (canceled) 
   
   
       23 . A stable pravastatin sodium tablet comprising:
 pravastatin sodium granules and a tablet filler wherein the granules exhibit a pH less than 9 as determined by dissolving the tablet in 900 ml of deionized water and are prepared by granulating a mixture comprising pravastatin sodium and a granulation filler with a granulating solution comprising water and a buffering agent and wherein the tablet retains 90 to 110 percent of an original pravastatin assay value after storage for 3 months at about 40° C. and 75% relative humidity;   and comprises 2-6 weight percent based upon the total weight of the tablet of buffering agent.   
   
   
       24 . The pravastatin tablet of  claim 23  wherein the buffering agent is sodium phosphate dibasic. 
   
   
       25 . The pravastatin tablet of  claim 23  wherein the buffering agent is tromethamine. 
   
   
       26 . The pravastatin tablet as defined in  claim 23  wherein the pH of the granules is less than 8.5. 
   
   
       27 . The pravastatin tablet as defined in  claim 24  wherein the pH of the granules is less than 8.0. 
   
   
       28 . The pharmaceutical composition as defined in  claim 23  wherein the pH of the granules is about 8 and does not exceed 9. 
   
   
       29 . The pravastatin tablet as defined in  claim 23  wherein the pH of the tablet is less than 9.0. 
   
   
       30 . The pravastatin tablet as defined in  claim 24  wherein the pH of the tablet is less than 8.5. 
   
   
       31 . The pharmaceutical composition as defined in  claim 23  wherein the pH of the tablet is about 8 and does not exceed 9.