Polymorphism of Thiamine Hydrochloride. II. Crystal Structure of Thiamine Hydrochloride Hemihydrate and Its Stability

Abstract

The content of water of crystallization in the phase II modification of thiamine hydrochloride has not previously been definitely determined. This is widely thought to be an anhydrous form, since it does not show any weight change on drying at 105° for 2hr. The present work describes the crystal structure of the phase II modification of thiamine hydrochloride crystals. It was found to be a hemihydrate and to be stable under normal conditions both in the solid state and in suspension in a saturated solution.