An objective of this invention is to provide a process for easily producing a crystal of compound (I) in industrial scale and a stable lyophilized composition of compound (I). The present invention provides a lyophilized composition in which the compound (I) is crystal and excellent in stability by lyophilizing an aqueous solution containing compound (I) and inorganic salts such as sodium chloride. In addition, even the lyophilized process is not conduct, a crystal of compound (I) can also be obtained from the aqueous solution.本發明之目的在於提供一種於工業規模上可簡便地製造化合物(I)之結晶的方法、及化合物(I)之安定的凍結乾燥組成物。本發明發現藉由將含有化合物(I)與氯化鈉等無機鹽之水溶液進行凍結乾燥，可得化合物(I)為結晶且保存安定性優異的凍結乾燥組成物，又，即使不進行凍結乾燥，亦可由該水溶液得到化合物(I)之結晶。
