Title: Water of Crystallization of Berberine Chloride
Abstract: Presence of anhydrous form and three hydrates of berberine chloride was confirmed by thermogravimetric analysis, differential thermal analysis, and X-ray diffractometry. The anhydrous form and monohydrate were very hygroscopic, and easily transformed to dihydrate at 12% relative humidity. Dihydrate was relatively hygroscopic and transformed to tetrahydrate at a high relative humidity. Tetrahydrate was transformed to dihydrate at 40-70°, to monohydrate at 80°, and to anhydrous form at above 90°. It was found that under ordinary storage condition, anhydrous form and monohydrate could not exist because of their remarkable hygroscopicity, and dihydrate and tetrahydrate were the stable phase. Commercial berberine chloride was a mixture of dihydrate and tetrahydrate.