title: Two solid forms of tauroursodeoxycholic acid and the effects of milling and storage temperature on solid-state transformations.
abstract: Two phase-pure solid forms of tauroursodeoxycholic acid (TUDCA) were prepared and characterized by thermal analysis, vibrational spectroscopy, X-ray diffraction, solid-state nuclear magnetic resonance, and morphological analysis. All solid forms can be produced from solvents and also can be obtained by mechanically and non-mechanically activated polymorph conversion. Near-infrared (NIR) spectroscopy, in combination with chemometrical techniques, was used for the quantitative monitoring of the polymorph conversion of TUDCA in milling process and at different storage temperatures. The NIR spectra in the range of 7139-5488 cm(-1) were considered for multivariate analysis. Results demonstrated that the NIR multivariate chemometric model can predict the percentage of crystal and amorphous TUDCA with the correlation coefficient of 0.9998, root mean square error of calibration of 0.740%, root mean square error of prediction of 0.698%, and root mean square error of cross-validation of 1.49%. In the milling process of crystal TUDCA (Form I), a direct transformation from crystal to glass was observed in 4h. Moreover, the impact of different storage temperatures on the stability of amorphous TUDCA was investigated, and the rate of polymorph transformation was found to be accelerated with increasing temperature.
authors.affiliation: College of Chemical Engineering, Sichuan University, Chengdu 610065, China.
authors.forename: Kailin
authors.initials: K
authors.lastname: Xu
authors.affiliation: College of Chemical Engineering, Sichuan University, Chengdu 610065, China.
authors.forename: Shoujun
authors.initials: S
authors.lastname: Zheng
authors.affiliation: Analytical & Testing Center, Sichuan University, Chengdu 610064, China.
authors.forename: Yuanming
authors.initials: Y
authors.lastname: Zhai
authors.affiliation: College of Chemical Engineering, Sichuan University, Chengdu 610065, China.
authors.forename: Liuqi
authors.initials: L
authors.lastname: Guo
authors.affiliation: College of Chemical Engineering, Sichuan University, Chengdu 610065, China.
authors.forename: Peixiao
authors.initials: P
authors.lastname: Tang
authors.affiliation: College of Chemical Engineering, Sichuan University, Chengdu 610065, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Yan
authors.affiliation: College of Chemical Engineering, Sichuan University, Chengdu 610065, China.
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.affiliation: College of Chemical Engineering, Sichuan University, Chengdu 610065, China. Electronic address: lihuilab@sina.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
mesh_terms: D002152:Calorimetry, Differential Scanning; D004339:Drug Compounding; D004355:Drug Stability; D004356:Drug Storage; D009682:Magnetic Resonance Spectroscopy; D033362:Powder Diffraction; D019265:Spectroscopy, Near-Infrared; D013655:Taurochenodeoxycholic Acid / Q000737:chemistry*; D013696:Temperature; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D013655:Taurochenodeoxycholic Acid; C031655:ursodoxicoltaurine
keywords: Amorphous; Milling; Polymorphism; Solid-state transformations; Tauroursodeoxycholic acid