The invention provides crystalline (2S)-3-[(3S,4S)-3-[(1R)-1-hydroxyethyl]-4-(4-methoxy-3-{[1-(5-methylpyridin-2-yl)azetidin-3-yl]oxy}phenyl)-3-methylpyrrolidin-1-yl]-3-oxopropane-1,2-diol, and pharmaceutical compositions thereof. The invention further provides methods of using this compound to treat overactive bladder.本發明提供(2S)-3-[(3S,4S)-3-[(1R)-1-羥乙基]-4-(4-甲氧基-3-{[1-(5-甲基吡啶-2-基)氮雜環丁-3-基]氧基}苯基)-3-甲基吡咯啶-1-基]-3-氧代丙烷-1,2-二醇結晶型,及其醫藥組合物。本發明進一步提供使用此化合物來治療膀胱過動症之方法。