THE PROCESS FOR PREPARING TAMIBAROTENE II TYPE CRYSTAL

摘要

The process for preparing tamibarotene II type crystal of a single heat-absorptive peak near 233 oC in differential scanning thermal analysis. The process comprises the following steps: using low carbon organic acids (preferred acetic acid or formic acid or their combination) or low carbon organic acids water solution to crystallize random crystal or amorphous tamibarotene solid to obtain pure tamibarotene II crystal. The method does not need high temperature transition process of more than 180 oC which is easy to cause degradation.