Characterization and Structure Analysis of Thiamine Hydrochloride Methanol Solvate

Abstract

Thiamine hydrochloride (THCl) forms a monomethanolate (MM) upon exposure of crystalline thiamine phases (thiamine hydrochloride hemihydrate/HH, nonstoichiometric hydrate/NSH, and anhydrate/AH) to anhydrous methanol (solvent and vapor). Desolvation of MM at 50-80°C resulted in the formation of a poorly crystalline intermediate which crystallized to AH at elevated temperatures (g150°C). When exposed to water vapor (11-75% RH, RT), MM transformed to HH (NSH was detected at e40% RH), while exposure to polar solvent vapor resulted in direct formation of AH. MM was stable in the presence of nonpolar (benzene and hexane) solvent vapor. Crystal structure analysis revealed a near identical H-bonding network in the two solvate (MM, and NSH with 1 mol water/mol THCl) lattices. The structure of MM as well as the solvent properties were identified as the key factors influencing both the kinetics of desolvation of MM and the nature of the product phase.

A Novel Shadowgraphic Inline Measurement Technique for Image-Based Crystal Size Distribution Analysis

“…However, this monohydrate is metastable at ambient conditions and converts fast into the thermodynamic stable thiamin hydrochloride hemihydrate. Hence, the solid-liquid equilibrium of the pseudo-monohydrate is difficult to measure, and therefore barely investigated [65,66]. Fortunately, data of the less-soluble thiamine hydrochloride hemihydrate in some binary solvents are reported, and therefore the experimental design was based on data of a binary water/ethanol mixture [67].…”

Polymorphism and Solvatomorphism 2010

“…124 Thiamine hydrochloride has been found to form a 1:1 methanol solvatomorph that could be desolvated to eventually form a stable anhydrate form. 125 However, when the methanol solvatomorph was exposed to water vapor, formation of a hemihydrate was observed.…”

Measurement of Solubility of Thiamine Hydrochloride Hemihydrate in Three Binary Solvents and Mixing Properties of Solutions

“…Once formed, the dehydration is initiated only when heated to 120 °C. 10,11 Because the crucial role of thiamine hydrochloride in the industry, it is necessary to find a suitable solvent for its separation and subsequent recrystallization to achieve the industrial scale synthesis with high purity. However, despite the fact that people have investigated much about the transformation among the five forms of thiamine hydrochloride, only a few have attempted to discuss its purification methods to obtain products with high yield and high purity.…”

“…67-03-08, Figure ) plays an important role in digestive system, nerve conduction and normal heart activity. − It is mainly used in animal feed and nutrient supplements in feed industries, medicines, cosmetics, other industries, and so on. , Up to now, there exist five solid-state forms of thiamine hydrochloride reported in the literature. − According to the literature, thiamine hydrochloride hemihydrate (HH) is the most stable form in contact with water. Once formed, the dehydration is initiated only when heated to 120 °C. , …”