Refining process of granisetron

The invention provides a refining process of granisetron, and relates to the technical field of medicines. According to the process, a final product is obtained through decoloration, hot filtration, devitrification, filtration, drying and crushing in a gradient cooling and heat preservation combined recrystallization form by using an ethanol/water green and economical solvent system, hot filtration is performed through a preheating pipeline, and the pressure is controlled, so that the solution is heated more uniformly, the recrystallization effect is better, and the purity of the product is improved. The purity of the granisetron can reach 99.9%, and the granisetron preparation method has great popularization value. 本发明提供了一种格拉司琼的精制工艺，涉及医药技术领域。该工艺，通过乙醇/水这种绿色经济型的溶剂体系，以梯度降温与保温相结合的重结晶形式，经过脱色、热过滤、析晶、过滤、干燥、粉碎得到最终产品，并且通过预热管道进行热过滤，并控制压力，使溶液受热更均匀，重结晶的效果更好，得到了一种纯度可达99.9％的格拉司琼，具有极大的推广价值。