1-[(2,6-Difluorophenyl)methyl]-1H-1,2,3-triazole-4-carboxamide, i.e. Rufinamide, is an anticonvulsant used in combination with other antiepileptic drugs in the treatment of a rare form of epilepsy, named Lennox-Gastaut syndrome.
Rufinamide, having formula (I), is known from EP 199262.

The chemical name 1-[(2,6-difluorophenyl)methyl]-1H-1,2,3-triazole-4carboxamide and the term Rufinamide are herein used interchangably, both in the disclosure and in the claims of the present application.
Various crystalline modifications of Rufinamide are known, for example the crystalline forms A and A′ are known from WO 98/56772, the forms B and C are known from EP 994863, and the forms α and β from US 2011/0034523.
WO98/56772 teaches that the polymorphic Form A, which is the more stable, can be obtained by precipitation from different solvents or mixtures thereof, for example water, methanol, ethanol or a methanol/formic acid mixture, in which the product 1-[(2,6-difluorophenyl)methyl]-1H-1,2,3-triazole-4-carboxamide is poorly soluble.
WO 98/56772 discloses the preparation of the crystalline Form C of Rufinamide through rapid crystallization from acetic acid, in which Rufinamide is moderately soluble, typically by cooling the solution over about 8 minutes, with a yield of about 67%.
As known, the synthesis processes commonly used to manufacture Rufinamide provide it in admixture with varying amounts of impurities, such as the ester of formula (II) and the acid of formula (III)

wherein R is an alkyl group, typically C1-C6 alkyl.
There is therefore the need for a process for the purification of Rufinamide, which provides an API (finished product) with high purity level and is industrially applicable.