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Preparation and transformation of true nifedipine polymorphs: investigated with differential scanning calorimetry and X-Ray diffraction pattern fitting methods

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dc.contributor.author Grooff, Driekus
dc.contributor.author Liebenberg, Wilna
dc.contributor.author De Villiers, Melgardt M.
dc.date.accessioned 2012-10-29T08:10:46Z
dc.date.available 2012-10-29T08:10:46Z
dc.date.issued 2011
dc.identifier.citation Grooff, D. et al. 2011. Preparation and transformation of true nifedipine polymorphs: investigated with differential scanning calorimetry and X-Ray diffraction pattern fitting methods. Journal of Pharmaceutical Sciences,100(5):1944-1957. [http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291520-6017/] en_US
dc.identifier.issn 0022-3549
dc.identifier.issn 1520-6017 (Online)
dc.identifier.uri http://hdl.handle.net/10394/7658
dc.description.abstract The amorphous → metastable and metastable → stable crystalline phase transitions of nifedipine and their relationship with polymorph composition during storage at controlled temperature/humidity conditions were investigated. Metastable form C was produced from both differential scanning calorimetry (DSC) thermal treatment and storage [22 °C/0% and 75% relative humidity (RH)] of the amorphous form. Amorphous conversion rate accelerated with storage temperature up to 40 °C, but a further 8 °C increase to 48 °C (3 °C above the glass transition) resulted in a more than 12-fold decrease in amorphous conversion rate. DSC and X-Ray diffraction (XRD) analysis revealed a faster amorphous conversion rate relative to the metastable crystal transformation with 75% RH having a greater accelerative effect on the former. Relative phase quantification from XRD pattern fitting included the use of integrated peak intensities of the crystalline phases, Rietveld and the Rietveld-based partial or no known crystal structures method. Kinetic analysis with Johnson-Mehl-Avrami equation indicated that the accelerated amorphous conversion in 75% RH was associated with a 10-fold increase in rate constant with dimensional growth little affected. The smaller rate increase for metastable crystal conversion was associated with an increased dimensional growth while the rate constant was little affected. en_US
dc.description.uri http://dx.doi.org/10.1002/jps.22419
dc.language.iso en en_US
dc.publisher Wiley en_US
dc.subject Nifedipine en_US
dc.subject physical stability en_US
dc.subject polymorphism en_US
dc.subject amorphous en_US
dc.subject kinetics en_US
dc.subject transformation en_US
dc.title Preparation and transformation of true nifedipine polymorphs: investigated with differential scanning calorimetry and X-Ray diffraction pattern fitting methods en_US
dc.type Article en_US


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