title: Study of complex formation of carbamazepine with thiourea.
abstract: The aim of this study, we evaluated a complex between thiourea (TU) and carbamazepine (CBZ) of a poorly soluble drug by using powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy, X-ray crystallography and the solubility test. PXRD of TU/CBZ=2/1, 1/1, and 1/2 prepared by solvent evaporation (EVP) revealed characteristic diffraction peaks at 2θ = 6.7°, 8.8°, 13.5°, and 20.4°, therefore molecular interaction between TU and CBZ presumably occurred. Results of the FT-IR spectroscopy, asymmetric and symmetric NH stretching vibration of TU were shifted to high region by TU/CBZ = 2/1, 1/1, and 1/2 EVP. TU/CBZ = 2/1 and 1/1 EVP had absorption derived from TU. It was considered that complex were formed by TU/CBZ = 1/2. X-Ray crystallography of TU and CBZ revealed a crystal structure with one TU molecule arranged near two CBZ molecules. Molecules of the same type overlap in this layer. When doing a solubility test by using CBZ and samples of EVP, physical mixture and crystals in TU/CBZ = 1/2 to confirm the solubility in water of TU/CBZ complex, there is no difference with the CBZ. It considered that the structure of a complex differs from the tunnel structure of inclusion complexes that has been previously reported contribute to result it.
authors.affiliation: Department of Drug Safety Management, Faculty of Pharmaceutical Sciences, Josai University.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Inoue
authors.forename: Sayuri
authors.initials: S
authors.lastname: Sato
authors.forename: Chisa
authors.initials: C
authors.lastname: Yamamoto
authors.forename: Mikio
authors.initials: M
authors.lastname: Yamasaki
authors.forename: Ikuo
authors.initials: I
authors.lastname: Kanamoto
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000737:chemistry*; D002220:Carbamazepine / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008958:Models, Molecular; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013890:Thiourea / Q000737:chemistry*
chemical_list: D018712:Analgesics, Non-Narcotic; D002220:Carbamazepine; D013890:Thiourea