| 摘要 |
An improved procedure for the purification of warfarin acid. Sodium, potassium and lithium warfarin salts and the corresponding clathrates are prepared in high, pharmacopeial grade purity and good yields from the pure warfarin acid and the respective metal salt bases in suitable media. The process for preparing pure warfarin acid from crude warfarin acid starts by suspending the crude acid in a water immiscible solvent, extracting the acid into an aqueous solution of dilute base, separating the resulting aqueous phase and diluting it with a lower alkyl alcohol. The aqueous solution is filtered before being diluted with the lower alkyl alcohol. The solution is acidified to a pH of about 2 to 5 using a suitable acid, such as hydrochloric, sulfuric or phosphoric acid. The resulting suspension is stirred at a temperature of from about to 20 DEG C to about 60 DEG C, cooling the suspension below room temperature, filtering the pure warfarin acid and drying. |
