Disclosed are crystalline oxalate salts of biphenyl-2-ylcarbamic acid 1-(2-{ [4-(4-{ [(R)-2-hydroxy-2-(8-hydroxy-2-oxo-1,2-dihydroquinolin-5-yl)ethylamino]-methyl} phenylcarbamoyl)butyl]methylcarbamoyl} ethyl)piperidin-4-yl ester wherein the crystalline oxalate salt is selected from: (a) an isopropanol solvate characterized by a powder x-ray diffraction pattern comprising diffraction peaks at 2theta values of 11.66±0.20, 15.75±0.20, 19.55±0.20, 23.00±0.20 and 23.45±0.20 and (b) a hydrate characterized by a powder x-ray diffraction pattern comprising diffraction peaks at 2theta values of 15.32±0.20, 16.90±0.20, 19.25±0.20 and 23.73±0.20. Also disclosed are compositions containing the crystalline oxalate salt and use of the salt to treat a pulmonary disorder and to processes for preparing the crystalline oxalate salt.
