title: Heating-induced phase transition of bupropion hydrobromide polymorphs.
abstract: Crystal phase transition and isothermal crystallization kinetics of bupropion hydrobromide is studied by thermal analysis, X-ray powder diffractometry, and scanning electron microscopy. As well known, bupropion hydrobromide has two stable polymorphic forms, form I and form II, during the production. Here it is found that form II will convert into form I with thermal treatment. Avrami exponent n is evaluated to be around 2.0 in the range 170°C-190°C, which indicates that the phase transition is a process of one-dimensional nucleation growth. This viewpoint is also confirmed by microscope morphology study. In addition, phase-transition active energy is calculated to be 239.4 kJ/mol, which means that a high energy barrier needs to be overcome to start up the phase transition.
authors.affiliation: Engineering Research Center for Eco-Dyeing and Finishing of Textiles, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China. zgq@zstu.edu.cn
authors.forename: Guoqing
authors.initials: G
authors.lastname: Zhang
authors.forename: Liping
authors.initials: L
authors.lastname: Gao
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Zhang
authors.forename: Lina
authors.initials: L
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Shao
mesh_terms: D001965:Bromides / Q000737:chemistry*; D016642:Bupropion / Q000031:analogs & derivatives / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D003460:Crystallization; D018360:Crystallography, X-Ray; D018765:Dopamine Uptake Inhibitors / Q000737:chemistry*; D006358:Hot Temperature; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D044367:Phase Transition; D033362:Powder Diffraction; D013678:Technology, Pharmaceutical / Q000379:methods
chemical_list: D001965:Bromides; D018765:Dopamine Uptake Inhibitors; D016642:Bupropion