Process-induced phase transformation of berberine chloride hydrates.

Berberine is a natural quaternary ammonium alkaloid used clinically in the chloride salt form for the treatment of diarrhea in many Asian countries. Although the hydrate formation of berberine chloride (BCl) is well documented, the associated mechanism and implications in pharmaceutical formulation have not been studied in detail. In this study, pure BCl dihydrate and BCl tetrahydrate were recrystallized from water and their phase transformation behaviors under defined conditions were investigated.