Patent ID: 7314639

Claim:
A method of preparing a crystal of 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-carbamoyl]benzoic acid, wherein the method comprises recrystallizing a starting crystal of 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-carbamoyl]benzoic acid from a mixture of water and ethanol and affords a crystal of 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-carbamoyl]benzoic acid which has a single endothermic peak approximately at 233° C. in differential scanning calorimetry and is suitable for use in a medicament.