(2S)-[4-(Carboxymethyl)thiazol-2-ylthio]-N-{[4-(3,4-dichlorobenzyl)morpholin-2-yl]methyl}acetamide hydrobromide and a crystal thereof, which resist easy weight change caused by vapor sorption as compared to a free form, and are superior as drug substances of pharmaceutical products, and a production intermediate therefor are provided.
