An improvement in the process of preparing ceftazidime pentahydrate from ceftazidime dihydrobromide which comprises commingling a secondary-amine-type ion-exchange resin such as Amberlite LA-2 in a water-immiscible organic solvent with an aqueous solution of the dihydrobromide stirring the mixture while maintaining a pH at or below about 6.0 and isolating ceftazidime pentahydrate from the aqueous layer.This process provides significantly higher yields of the pentahydrate than previously could be...

X-6529 Ceftazidime pentahydrate is formulated with a pharmaceutically-acceptable base and amorphous lactose to provide stabilized pharmaceutically-acceptable formulations.

Ceftazidime pentahydrate is obtained in purified crystalline form in a process comprising acidification of an aqueous solution of ceftazidime to about the optimum pH for nucleation of between about 4.0 and about 4.7 and maintenance at the optimum pH during crystallization. The crystalline product obtained exhibits enhanced stability toward polymer formation when stressed.

X-6453 Crystalline (6R,7R)-7-(Z)-2-(2-tritylamino-thiazol-4-yl)-2-(2-t-butyloxycarbonylprop-2-oxyimino)-acetamido!-3-(1-pyridiniummethyl)-3-cephem-4-carboxylic acid dihydrobromide salt, intermediate to the antibiotic ceftazidime, is provided.

Ceftazidime bishydrobromide crystalline monohydrates, useful for preparing crystalline ceftazidime pentahydrate, are provided.

7-(R)-Amino-3-(l-pyridiniummethyl)-ceph-3-em-4-carboxylate monohydrochloride monohydrate compound is useful as an intermediate in the synthesis of ceftazidime.