Thermally Induced Phenomena in Amorphous Nifedipine: The Correlation Between the Structural Relaxation and Crystal Growth Kinetics
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F25%3A39923087" target="_blank" >RIV/00216275:25310/25:39923087 - isvavai.cz</a>
Result on the web
<a href="https://doi.org/10.3390/molecules30010175" target="_blank" >https://doi.org/10.3390/molecules30010175</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.3390/molecules30010175" target="_blank" >10.3390/molecules30010175</a>
Alternative languages
Result language
angličtina
Original language name
Thermally Induced Phenomena in Amorphous Nifedipine: The Correlation Between the Structural Relaxation and Crystal Growth Kinetics
Original language description
The particle size-dependent processes of structural relaxation and crystal growth in amorphous nifedipine were studied by means of non-isothermal differential scanning calorimetry (DSC) and Raman microscopy. The enthalpy relaxation was described in terms of the Tool-Narayanaswamy-Moynihan model, with the relaxation motions exhibiting the activation energy of 279 kJ.mol(-1) for the temperature shift, but with a significantly higher value of similar to 500 kJ.mol(-1) being obtained for the rapid transition from the glassy to the undercooled liquid state (the latter is in agreement with the activation energy of the viscous flow). This may suggest different types of relaxation kinetics manifesting during slow and rapid heating, with only a certain portion of the relaxation motions occurring that are dependent on the parameters of a given temperature range and time frame. The DSC-recorded crystallization was found to be complex, consisting of four sub-processes: primary crystal growth of alpha(p) and beta(p) polymorphs, enantiotropic beta(p) -> beta(p)' transformation, and beta(p)/beta(p)' -> alpha(p) recrystallization. Overall, nifedipine was found to be prone to the rapid glass-crystal growth that occurs below the glass transition temperature; a tendency of low-temperature degradation of the amorphous phase markedly increased with decreasing particle size (the main reason being the increased number of surface and bulk micro-cracks and mechanically induced defects). The activation energies of the DSC-monitored crystallization processes varied in the 100-125 kJ.mol(-1) range, which is in agreement with the microscopically measured activation energies of crystal growth. Considering the potential correlations between the structural relaxation and crystal growth processes interpreted within the Transition Zone Theory, a certain threshold in the complexity and magnitude of the cooperating regions (as determined from the structural relaxation) may exist, which can lead to a slow-down of the crystal growth if exceeded.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10400 - Chemical sciences
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Molecules
ISSN
1420-3049
e-ISSN
1420-3049
Volume of the periodical
30
Issue of the periodical within the volume
1
Country of publishing house
CH - SWITZERLAND
Number of pages
26
Pages from-to
175
UT code for WoS article
001395051100001
EID of the result in the Scopus database
2-s2.0-85214523409