Study On The Crystallization Process Of Cefminox Sodium

Cefminox sodium contains seven crystal waters and is an antibiotics with dual antibacterial mechanism,which has the advantages of high efficiency,wide spectrum and small side effects.In recent years,cefminox sodium accounts for an increasing proportion in the domestic antibiotics market.In order to solve the problems of small particle size,low yield and big difference between batches of cefminox sodium produced in China,the crystallization process of cefminox sodium was systematically studied and an optimized crystallization process was developed in this paper.The obtained results can provid basic data for its industrial production.The crystal microstructure of cefminox sodium was characterized by X-ray powder diffraction.Using Materials Studio(M.S.)software,the cell parameters of cefminox sodium were calculated from scratch,in which the microstructurral features of cefminox sodium,such as crystal system and space group,were determined.The non-isothermal dehydration process of cefminox sodium was studied by thermal analysis technique.The thermal analysis data were correlated by differential equation and integral equation,respectively.The dehydration mechanism function of cefminox sodium hydrate can be described by Jander equation(n = 2),and the non-isothermal dehydration kinetics model of cefminox sodium hydrate was established.Dynamic laser method was used to determine the solubility of cefminox sodium in water,methanol,ethanol and acetone at different temperatures,and Apelblat equation was used to fit the experimental data.The solubility of cefminox sodium in different binary mixed solvents,such as water-acetone and water-ethanol,was measured at different temperatures.The solubility data were fitted by Apelblat equation and CNIBS/Redlich-Kister equation,and the model parameters were obtained.The thermodynamic properties of cefminox sodium during dissolution such as the standard Entropy,Enthalpy and Gibbs free energy were also studied.According to the thermodynamic properties of crystallization of cefminox sodium,the anti-solvent crystallization scheme of cefminox sodium was determined.The single factor method was introduced to investigate the effects of different operating parameters on the recrystallization of cefminox sodium.Based on the resluts of the crystal structure,dehydration kinetics and crystallization thermodynamics of cefminox sodium,the optimized operation schedule of the crystallization process was obtained.The cefminox sodium crystal with the average particle size of 186 ?m was obtained by using the optimal crystallization process.Morerover,the yield of cefminox sodium crystal can reach 87.29%.