Temperature stable crystalline di(1-methyl-2-pyrralidinone) and di(N- formylpyrrolidine) adducts of cephalosporin derivatives

摘要

Crystalline adducts of 7-[(Z)-2-methoxyimino-2-(2-aminothiazol- 4-yl) acetamido-3-[(1-methyl-1-pyrro lidinium)methyl]-3-cephem-4- carboxylate selected from the group consisting of the di(1-methyl-2- pyrrolidinone) adduct and the di(N-formyl pyrrolidine) adduct and salt complexes thereof have been found to be stable at even high temperatures. The crystalline adducts are prepared by forming an admixture of adducting agents, zwitterions and seed adduct crystals and inducing crystallization followed by isolating the crystals. A process for preparing adduct salt complexes is also disclosed. Crystalline zwitterion can be formed by slurrying the adducts in a solvent which removes the adducting agents.