Methods of preparing (+)-1,4-dihydro-7-[(3S,4S)-3-methoxy-4-(methylamino)-1-pyrrolidinyl]-4-oxo-1-(2-thiazolyl)-1,8-naphthyridine-3-carboxylic acid are disclosed. Also provided are pharmaceutical compositions comprising (+)-1,4-dihydro-7-[(3S,4S)-3-methoxy-4-(methylamino)-1-pyrrolidinyl]-4-oxo-1-(2-thiazolyl)-1,8-naphthyridine-3-carboxylic acid, and methods of treatment using such compositions.本發明揭示一種製備(+)-1,4-二氫-7-[(3S,4S)-3-甲氧基-4-(甲胺基)-1-吡咯啶基]-4-酮基-1-(2-噻唑基)-1,8-萘啶-3-羧酸之方法。本發明亦提供一種包含(+)-1,4-二氫-7-[(3S,4S)-3-甲氧基-4-(甲胺基)-1-吡咯啶基]-4-酮基-1-(2-噻唑基)-1,8-萘啶-3-羧酸之醫藥組合物及使用該等組合物之治療方法。