title: Study of the pseudo-crystalline transformation from form i to form II of thiamine hydrochloride (vitamin B(1)).
abstract: The purpose of the current study was to evaluate the rate of the pseudo-crystalline transformation of thiamine hydrochloride form I to form II depending on the temperature and humidity. Changes in the appearance and weight of form I crystals were observed under humidified conditions using a water vapor sorption system equipped with a CCD camera. The form I crystals and tablets were stored under various temperature and humidity conditions (the saturation salt desiccator method), and the pseudo-crystalline transformation was observed using X-ray powder diffractometry with our laboratory equipment for drug substances and using synchrotron X-ray powder diffractometry for tablets. It was confirmed that the activation energy in the pseudo-crystalline transformation rate from form I to form II was dependent on humidity, and the calculated values were 121-155 kJ/mol at 70-90% relative humidity. Moreover, when thiamine hydrochloride was formulated as tablets, it was confirmed that the transformation rate was slower compared with the drug substances alone. The pseudo-crystalline transformation rate therefore declined after formulation in tablet form, perhaps due to the shielding effects of thiamine hydrochloride crystal from contact with water molecules by excipients, compaction, etc.
authors.affiliation: Department I, Medicinal Chemistry Research Laboratory I, Research Division, Mitsubishi Tanabe Pharma Corporation, Yokohama, Kanagawa, Japan. Masuda.Katsuhiko@mk.mt-pharma.co.jp
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Masuda
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ishige
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yamada
authors.forename: Kotaro
authors.initials: K
authors.lastname: Fujii
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Uekusa
authors.forename: Keiko
authors.initials: K
authors.lastname: Miura
authors.forename: Etsuo
authors.initials: E
authors.lastname: Yonemochi
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Terada
mesh_terms: D003460:Crystallization; D006813:Humidity; D013607:Tablets / Q000737:chemistry; D013696:Temperature; D013831:Thiamine / Q000737:chemistry*; D014741:Video Recording; D014961:X-Ray Diffraction
chemical_list: D013607:Tablets; D013831:Thiamine