Patent ID: 7435832

Claim:
A method of preparing an anhydrous crystal of a malic acid salt of N-[2-(diethylamino)ethyl]-5-[(5-fluoro-1,2-dihydro-2-oxo-3H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide of Crystal Form I having a characteristic X-ray diffraction data pattern in accordance with FIG. 1 , the method comprising: combining malic acid; N-[2-(diethylamino)ethyl]-5-[(5-fluoro-1,2-dihydro-2-oxo-3H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide; and a solvent; and inducing the salt to crystallize under crystallization conditions comprising one or more factors comprising: a difference between the initial and final temperatures of the crystallization solution of at most about 100° C.; a rate of cooling of at most about 50° C. per hour; no seeding; a supersaturation ratio of at most about 10; no precipitant; and/or combinations thereof.