Patent ID: 7365224

Claim:
Isolated orthorhombic crystalline 4-[6-acetyl-3-[3-(4-acetyl-3-hydroxy-2-propylphenylthio)propoxy]-2-propyl- phenoxy]butyric acid, prepared by the method of: dissolving 4-[6-acetyl-3-[3 -(4-acetyl-3-hydroxy-2-propylphenylthio)propoxy]-2-propyl-phenoxy]butyric acid in ethanol, adding water and cooling the resulting mixture first to about 10-15° C. and second to about 5-10° C., adding more water, agitating the resulting mixture at about 5-10° C., and isolating the orthorhombic crystals of 4-[6-acetyl-3-[3-(4-acetyl-3-hydroxy-2-propylphenylthio)propoxy]-2-propyl-phenoxy]butyric acid, wherein the isolated orthorhombic crystals of 4-[6-acetyl-3-[3-(4-acetyl-3-hydroxy-2-propylphenylthio)propoxy]-2-propyl-phenoxy]butyric acid are substantially free of monoclinic crystalline forms as evidenced by powder x-ray diffraction analysis showing the absence of doublet peaks between about 11.5 and 16 (2-Theta scale).