Crystal forms of SK-3530

The objective of this work was to investigate the existence of polymorphs of SK-3530 and the transformation of crystal forms. Two crystal forms of SK-3530 have been isolated by recrystallization and characterized by differential scanning calorimetry, powder X-ray diffractometry and thermogravimetric analysis. The differential scanning calorimetry and powder X-ray diffractometry patterns of two crystal forms were different respectively. After storage of 1 month at 0% RH (silica gel, 20°C), 52% RH (saturated solution of Na 2 Cr 2 O 7 ·2H 2 O/20°C) and 95% RH (saturated solution of Na 2 HPO 4 /20°C), Form 2 was not transformed to Form 1 and two forms were shown to have a good physical stability at room temperature for 1 month. In the dissolution studies in pH 6.8 buffer at 37 ± 0.5°C, the dissolution rate of Form 2 was significantly higher than that of Form 1 under 30 min.