Thermodynamically stable form of (R)-3- (4-fluorophenyl) sulphonylamino -1,2,3,4- tetrahydro -9H-carbazole -9-propanoic acid (ramatroban)

摘要

The present invention relates to a thermodynamically stable modification of the active compound ramatroban, of which the formula is (R)-3-[[(4-fluorophenyl) sulphonyl] amino]-1,2,3,4-tetra-hydro-9H-carbazole-9-propanoic acid. The thermodynamically stable form is prepared either by melting of the metastable form and subsequent recrystallization or by seeding a solution of the metastable active compound with a seed crystal of the thermodynamically stable form. The thermodynamically stable active compound can be used in the control of diseases.