Insight into the conformational polymorph transformation of a block-buster multiple sclerosis drug fingolimod hydrochloride (FTY 720)

- Three polymorphic forms of the immunomodulatory drug, fingolimod hydrochloride (FTY 720), are highly temperature dependent.
- The reversible single-crystal to single-crystal transformations were studied using different analytical techniques (XRD, DSC, and Raman).
- Form I is stable at ambient condition, while II and III could change to I when appropriate temperature applied.