Polymorph control of 5-fluorouracil during a ball milling process

Polymorph control of 5-fluorouracil (5-FU) was achieved by ball milling. Form II was synthesized through one-step neat grinding of raw 5-FU (RFU), and Form III (a new polymorph) was obtained by neat grinding RFU twice. Forms II and III of 5-FU were prepared separately through ball milling with different amounts of ethanol as an additive at the same period without influencing each other.