Cefixime crystallization methods

The present invention belongs to the field of medical technology, it relates to a method of crystallization of cefixime. The method comprising: cefixime salt solution or a mixture of water and an organic solvent and water, at a temperature of 0 ~ 40 ℃, addition of the acid, the solution was adjusted to pH 3.0 to 3.5, while stirring, and with on-line pH meter monitoring system pH, as cefixime crystals precipitated, the pH of the system begins to rise, this time through the continuous dropwise addition of acid and acid dropping control, so that the system has a stable pH in the range of 3.0 to 3.5, so that the crystal has been cefixime pH = 3.0 to 3.5 to precipitate a narrow range; until when the pH of the system does not fluctuate up without acid added dropwise in 3.0-3.5 stable for at least 30 min, stop acid was added, with stirring, then filtered, washed, and dried, to give cephem cefixime crystals. Large crystals according to the method of cefixime bulk density obtained by the present invention, good stability, particularly suitable for formulation into capsules.