Patent ID: 8203019

Claim:
A method of producing a compound (−)-halofenate in a crystalline solid form A characterized by at least one of: a) an infra red spectrum substantially in accordance with FIG. 3 ; b) a Raman spectrum substantially in accordance with FIG. 5 ; c) an X-ray powder diffraction pattern substantially in accordance with FIG. 1 ; and d) a DSC scan substantially in accordance with FIG. 7 ; the method comprising at least one of: (i) heating (−)-halofenate in at least one solvent selected from the group consisting of heptane, 2-propanol, and combinations thereof; crystallizing at a temperature of from about 50° C. to −10° C. and drying until the crystals contain less than 0.05% solvent; (ii) drying a crystal of solid form B of (−)-halofenate; (iii) drying a crystal of solid form C of (−)-halofenate; (iv) heating (−)-halofenate in at least one solvent selected from the group consisting of heptane, 2-propanol, and combinations thereof; crystallizing in the presence of a crystal of a solid form of (−)-halofenate at a temperature of from about 50° C. to −10° C. and drying until the crystals contain less than 0.05% solvent; and (v) crystallizing (−)-halofenate from at least one solvent selected from the group consisting of acetonitrile, benzene, cyclohexanol, t-butyl methyl ether, methanol, methyl ethyl ketone, toluene, tetrahydrofuran and combinations thereof and drying.