| 摘要 |
1426266 Cephradine dihydrate E R SQUIBB & SONS Inc 4 May 1973 [1 June 1972] 21368/73 Heading C2C The novel compound cephradine dihydrate (being the dihydrate of the known cephalosporin compound cephradine, which is 7-(D-α- amino - 1,4 - cyclohexadien - 1 - ylacetamido) desacetoxycephalosporanic acid) is prepared by neutralizing an acid addition salt of base salt of cephradine in aqueous solution or suspension at a temperature of 0‹ to 25‹ C. By the word "neutralizing" is meant bringing to the point at which the acid or base moiety of the acid addition or base salt is exactly neutralized by the added base or acid respectively, this point being about pH 5À5 rather than the conventional pH 7 of a strong acid/strong base interaction. The dihydrate, which is isolated by crystallization (preferably after seeding), has a characteristic X-ray diffraction pattern (using a copper K-αradiation source), and differs from known cephradine in its crystalline form, water-solubility and behaviour on vacuum drying at elevated temperature which converts the dihydrate irreversibly into the conventional form of cephradine. The novel cephradine dihydrate may be made up into antibiotically active pharmaceutical compositions with a pharmaceutically acceptable diluent or carrier. |
