| abstract |
A method for producing a drug substance of crystalline pitavastatin calcium excellent in stability, is presented. In the production of a compound (pitavastatin calcium) represented by the formula ( 1 ): n n n n n n n n n n The water content is adjusted to a level of from 5 to 15%, and the crystal form is controlled to be crystal form A, thereby to obtain a drug substance excellent in stability. |