New crystal form of (R)-Lansoprazole sodium and preparation method thereof

The invention discloses a new crystal form A of a (R)-Lansoprazole sodium dimethylacetamide solvate and a preparation method thereof. The powder X-ray diffraction spectrum has the feature diffraction peak in the position where the diffraction angle 2Theta is 5.9, 7.6, 12.2, 12.7, 16.6, 18.4, 20.5, 25.8, 26.8 and 31.4 degrees. The preparation method for the new crystal form A comprises the following steps: adding the (R)-Lansoprazole sodium to a mixed solvent of the dimethylacetamide and water, adding the suitable amount of a viscosity modifier and an antioxidant, adding a poor solvent after dissolving and clarifying, and slowly crystallizing to obtain the new crystal form A. The new crystal form A of the (R)-Lansoprazole sodium dimethylacetamide solvate has the advantages of moderate crystal granularity, good mobility, difficult aggregation and degradation, and good stability, and is suitable for the hot-melting extrusion process. The preparation process of the new crystal form A is simple, the cost is low, the yield is high, the solvent is safe and non-toxic, and the new crystal form A is suitable for the industrial production.