Crystalline polymorphs of methanesulfonic acid addition salts of Imatinib

A process for the preparation of the α-crystal form of the methanesulfonic acid addition salt of 4-(4-methylpiperazin-1-ylmethyl)-N-[4-methyl-3-[4-pyridin-3-yl)pyrimidin-2-ylamino]phenyl]benzamide comprising:

• a) carrying out an acid addition reaction using not more than 0.99 equivalents of methanesulfonic acid per 1 equivalent of 4-(4-methylpiperazin-1-ylmethyl)-N-[4-methyl-3-[(4-pyridin-3-yl)pyrimidin-2-ylamino)phenyl]benzamide, in a solvent selected from the group consisting of C2-C6 aliphatic alcohols and the mixtures thereof, optionally with the addition of a C1-C4 aliphatic alcohol;
• b) optionally adding a solvent selected from the group consisting of esters formed from a C1-C4 aliphatic alcohol and formic acid, acetic acid, or propionic acid;
• c) optionally inoculating the reaction mixture with the α-crystal form;
• d) stirring the reaction mixture for the time necessary for crystallization of the α-crystal form;
• and
• e) isolating the α-crystal form from the reaction mixture,
• wherein said α-crystal form of the methanesulfonic acid addition salt of 4-(4-methylpiperazin-1-ylmethyl)-N-[4-methyl-3-[(4-pyridin-3-yl)pyrimidin-2-ylamino)phenyl]benzamide isolated from the reaction mixture shows an X-ray powder diffraction pattern that is characterized by having peaks at 2θ angles of approximately:
• 4.9;
• 18.6;
• 19.1;
• 23.2 and 28.6°.