In situ monitoring of stirring effects on polymorphic transformations during cooling crystallization of carbamazepine
Sypek, Katarzyna Joanna and Burns, Iain and Florence, Alastair and Sefcik, Jan (2012) In situ monitoring of stirring effects on polymorphic transformations during cooling crystallization of carbamazepine. Crystal Growth and Design, 12 (10). pp. 4821-4828. ISSN 1528-7483 (https://doi.org/10.1021/cg3005689)
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The influence of experimental conditions on polymorphic outcome and transformations during cooling crystallization of carbamazepine (CBZ) from anhydrous ethanol has been investigated. Stirring was found to be the most important controlling factor for the initial polymorphic outcome in solutions prepared using commercial CBZ powder. For quiescent conditions, a few large crystals of the metastable trigonal α form (II) initially appeared, undergoing subsequent slow transformation into the stable P-monoclinic β form (III). Under sufficiently vigorous stirring, the induction times observed were clearly defined by the onset of turbidity, which was due to formation of a large number of small form III prismatic crystals. In experiments with solutions prepared by using recrystallized CBZ, significantly shorter induction times were observed under stirring conditions: a large number of small form II needle-shaped crystals initially formed at the onset of turbidity and then relatively rapidly transformed to small crystals of form III. This indicates a possible effect of impurities in the commercial CBZ powder inhibiting rapid nucleation of form II under stirring conditions. In situ monitoring of CBZ polymorphic outcome was performed using custom-built experimental setup for simultaneous measurement of intensity of transmitted and scattered light. Distinct pathways in two-variable intensity plots were observed for formation of each respective polymorph under stirring conditions. The same monitoring technique should be readily applicable to other systems.
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Item type: Article ID code: 41857 Dates: DateEvent2012Published12 September 2012Published OnlineSubjects: Technology > Chemical engineering
Medicine > Pharmacy and materia medicaDepartment: Faculty of Engineering > Chemical and Process Engineering
Technology and Innovation Centre > Continuous Manufacturing and Crystallisation (CMAC)
Faculty of Science > Strathclyde Institute of Pharmacy and Biomedical Sciences
Technology and Innovation Centre > BionanotechnologyDepositing user: Pure Administrator Date deposited: 31 Oct 2012 17:00 Last modified: 14 Apr 2024 00:25 Related URLs: URI: https://strathprints.strath.ac.uk/id/eprint/41857