Uniform evaluation method and optical purity of toshiru Acid supuratasuto crystal being uniform, stability offer of crystal and its manufacturing method. In the manner which evaluates the uniformity of toshiru Acid supuratasuto crystal, uniform evaluation method of the toshiru Acid supuratasuto crystal which features that (a) it dissolves the tonnage of the 3% or less in toshiru Acid supuratasuto crystal including the solvent, it takes the portion of suspension supernatant it is obtained and the process which measures optical purity, (b) next, it dissolves the entire quantity in remaining suspensoid including the solvent, takes the portion of that solution and it consists of the process which measures optical purity, aforementioned process (a) with process (b) it contrasts optical purity, and the toshiru Acid which is superior in uniformity and thermal stabilitysupuratasuto crystal and its manufacturing method.トシル酸スプラタスト結晶の均一性の評価方法並びに光学純度が均一で安定な結晶及びその製法の提供。トシル酸スプラタスト結晶の均一性を評価する方法において、(a)トシル酸スプラタスト結晶に溶媒を加えてその3%以下の量を溶解し、得られる懸濁上清の一部を取り光学純度を測定する工程、(b)次に、残りの懸濁液に溶媒を加えて全量を溶解し、その溶液の一部を取り光学純度を測定する工程からなり、前記工程(a)と工程(b)の光学純度を対比することを特徴とするトシル酸スプラタスト結晶の均一性の評価方法、並びに均一性及び熱安定性に優れるトシル酸スプラタスト結晶及びその製法。
