Patent ID: 7132549

Claim:
A process for preparing anhydrous eletriptan hemisulphate form I polymorph characterized by a powder X-ray diffraction pattern obtained using copper K-alpha 1 radiation (λ=0.15406 nm) which shows main peaks at 9.28, 10.38, 11.37, 12.40, 16.84, 17.46, 17.53, 17.78, 17.98, 19.48, 20.70, 21.29, 21.45, 22.21, 22.64, 23.08, 25.20 and 25.79, comprising the steps of (a) slurrying any other form of eletriptan hemisulphate in a solvent of the formula CH 3 COOR, wherein R is a C 1 –C 6 alkyl group; (b) adjusting the water content of the slurry, if necessary, to 3% volume/volume or less; (c) heating the slurry; (d) concentrating the reaction mixture by azeotropic distillation, if necessary, until the water content of the reaction mixture has fallen to below 1% volume/volume; and (e) recovering the product.