| abstract |
Hydrates of acid addition bis salts of anthranilic acid derivatives are prepared by the following method: (A) combining an anthranilic acid derivative, a pharmaceutically acceptable organic solvent, excess water and a strong pharmaceutically acceptable strong acid in any order to form a mixture; (B) warming the mixture until a clear solution is formed; (C) filtering the solution while warm to obtain a filtrate, and (d) recovering the hydrate as defined above from the filtrate. The hydrate has a specific number of moles of water of crystallization and has good storage stability and solubility characteristics over the hydrates of such acid addition bis salts prepared by conventional methods. |