| 摘要 |
Provided is a crystallization method for reducing the level of impurities in calcipotriene in which a solution of a starting calcipotriene in a first process solvent, for example THF, is combined with second process solvent, for example methyl formate, and, after cooling, calcipotriene is isolated. The method can include a slurry step for reducing the level of residual first process solvent.
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