Crystallization method for preparing amorphous esomeprazole magnesium salt

The invention relates to a crystallization method for preparing amorphous esomeprazole magnesium salt and belongs to the technical field of discovery and preparation of a medicine crystal form. The method comprises the following four steps: (1) mixing esomeprazole sodium salt, a water absorbent and ethanol at a suitable temperature according to a certain mass volume ratio; (2) adding ethanol solution of MgCl2*6H2O into the system to perform the reaction to obtain esomeprazole magnesium salt; (3) filtering to remove inorganic salt impurities and after concentrating filtrate, dropwise adding a proper quantity of dissolving agent acetonitrile; (4) washing the obtained precipitates by acetonitrile and carrying out vacuum drying to obtain the target product. By detection of analysis methods such as X-ray powder diffraction (PXRD), differential scanning calorimetry (DSC), infrared spectroscopy (IR) and the like, the target product is the amorphous esomeprazole magnesium salt and does not comprise other impurity crystal forms. Compared with an existing preparation method, the crystallization method has the advantages that the obtained product has higher crystal form purity, clarity and yield.