Crystalline and pure modafinil, and process of preparing the same

摘要

Described is a process for preparing modafinil, whereby it may be isolated in high purity by a single crystallization. The process produces modafinil free of sulphone products of over-oxidation and other by-products. Further provided is crystalline Forms II-VI of modafinil and processes for preparing them. Each of the forms is differentiated by a unique powder X-ray diffraction pattern. Pharmaceutical compositions containing modafinil Forms II-IV and VI are also described.