Provided is a crystalline form of N-[1-(2-methoxyethyl)-piperidin-4-yl]-2-[2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-1-yl]-N-(4&rsquo-trifluoromethylbiphenyl-4-ylmethyl)acetamide (rilapladib). The compound is a Lp-PLA2 inhibitor.The compound may be useful in the treatment of Alzheimer&rsquos disease.