Two Cocrystal Polymorphs of Palmatine Chloride with Racemic Hesperetin

Two polymorphic cocrystals of palmatine chloride with racemic hesperetin (Form I and Form II) have been prepared and investigated systematically. Crystal structure analysis reveals that reliable O-H···Cl– hydrogen-bonding interactions exist in both cocrystal polymorphs. However, similar O-H···Cl– hydrogen-bonding interactions resulted in completely different supramolecular arrangements. Cocrystal Forms I and II are non-hygroscopic and show high stability against temperature, humidity, and light. The cocrystal formation greatly lowers the solubility of palmatine chloride, while the solubility of hesperetin has been improved. Sustained release of palmatine chloride and enhanced release of hesperetin from two cocrystal polymorphs in pure water were achieved.