Physicochemical and crystal structure analysis of pranlukast pseudo-polymorphs II: Solvate and cocrystal.

Pranlukast (PRS) is a leukotriene receptor antagonist for the treatment of bronchial asthma. In this study, six new solvates and one new cocrystal of PRS were characterized by PXRD, TG-DTA, DSC, vapor sorption analysis and the dissolution test. In addition, the crystal structures were determined by single crystal X-ray structure analysis. PRS was found to be a rare example of a promiscuous multicomponent crystal former. The crystal packing patterns of these crystals can be categorized into the sheet-like and channel-like patterns. The ethanol solvate (PRS/ethanol) and urea cocrystal (PRS/urea) were more stable than the others under humid conditions. PRS/ethanol showed an improved dissolution profile compared to PRS HH and PRS/urea.