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 degrees C), 52% RH (saturated solution of Na2Cr2O7 center dot 2H(2)O/20 degrees C) and 95% RH (saturated solution of Na2HPO4/20 degrees 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 degrees C, the dissolution rate of Form 2 was significantly higher than that of Form 1 under 30 min.