Kinetics of Phase Transitions in Amorphous Carbamazepine: From Sub-Tg Structural Relaxation to High-Temperature Decomposition

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F25%3A39923100" target="_blank" >RIV/00216275:25310/25:39923100 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.3390/ijms26136136" target="_blank" >https://doi.org/10.3390/ijms26136136</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3390/ijms26136136" target="_blank" >10.3390/ijms26136136</a>

Result language

angličtina

Original language name

Kinetics of Phase Transitions in Amorphous Carbamazepine: From Sub-Tg Structural Relaxation to High-Temperature Decomposition

Original language description

Thermokinetic characterization of amorphous carbamazepine was performed utilizing non-isothermal differential scanning calorimetry (DSC) and thermogravimetry (TGA). Structural relaxation of the amorphous matrix was described in terms of the Tool-Narayanaswamy-Moynihan model with the following parameters: Delta h* approximate to 200-300 kJ center dot mol(-1), beta = 0.57, x = 0.44. The crystallization of the amorphous phase was modeled using complex Sestak-Berggren kinetics, which incorporates temperature-dependent activation energy and degree of autocatalysis. The activation energy of the crystal growth was determined to be &gt;320 kJ center dot mol(-1) at the glass transition temperature (T-g). Owing to such a high value, the amorphous carbamazepine is stable at T-g, allowing for extensive processing of the amorphous phase (e.g., self-healing of the quench-induced mechanical defects or internal stress). A discussion was conducted regarding the converse relation between the activation energies of relaxation and crystal growth, which is possibly responsible for the absence of sub-T-g crystal growth modes. The high-temperature thermal decomposition of carbamazepine proceeds via multistep kinetics, identically in both an inert and an oxidizing atmosphere. A complex reaction mechanism, consisting of a series of consecutive and competing reactions, was proposed to explain the second decomposition step, which exhibited a temporary mass increase. Whereas a negligible degree of carbamazepine degradation was predicted for the temperature characteristic of the pharmaceutical hot-melt extrusion (similar to 150 degrees C), the degradation risk during the pharmaceutical 3D printing was calculated to be considerably higher (1-2% mass loss at temperatures 190-200 degrees C).

Czech name

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Czech description

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Type

J_imp - 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

Project

—

Continuities

S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

International Journal of Molecular Sciences

ISSN

1661-6596

e-ISSN

1422-0067

Volume of the periodical

26

Issue of the periodical within the volume

13

Country of publishing house

CH - SWITZERLAND

Number of pages

25

Pages from-to

6136

UT code for WoS article

001527270600001

EID of the result in the Scopus database

2-s2.0-105010456287