Determination of the glass transition temperature of cyclodextrin polymers

•Two cyclodextrin polymers were found to be amorphous.•The glass transitions were located above the thermal degradation.•The glass transitions were estimated by mixing cyclodextrin polymers with plasticizers.•Homogeneous mixtures were obtained by co-milling and a melt-quenching. The aim of this work...

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Bibliographic Details
Published in:Carbohydrate polymers 2016-09, Vol.148, p.172-180
Main Authors: Tabary, Nicolas, Garcia-Fernandez, Maria Jose, Danède, Florence, Descamps, Marc, Martel, Bernard, Willart, Jean-François
Format: Article
Language:English
Subjects:
Amorphous state
Calorimetry, Differential Scanning
Cellulose - chemistry
Chemistry, Pharmaceutical
Cyclodextrins - chemistry
Delayed-Action Preparations - chemistry
DSC
Glass transition
Plasticization
Transition Temperature
X-Ray Diffraction
β-cyclodextrin polymers
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Summary:•Two cyclodextrin polymers were found to be amorphous.•The glass transitions were located above the thermal degradation.•The glass transitions were estimated by mixing cyclodextrin polymers with plasticizers.•Homogeneous mixtures were obtained by co-milling and a melt-quenching. The aim of this work was to determine the main physical characteristics of β-cyclodextrin polymers, well known for improving complexation capacities and providing enhanced and sustained release of a large panel of drugs. Two polymers were investigated: a polymer of β-cyclodextrin (polyβ-CD) and a polymer of partially methylated (DS=0.57) β-cyclodextrin (polyMe-β-CD). The physical characterizations were performed by powder X-ray diffraction and differential scanning calorimetry. The results indicate that these polymers are amorphous and that their glass transition is located above the thermal degradation point of the materials preventing their direct observation and thus their full characterization. We could however estimate the virtual glass transition temperatures by mixing the polymers with different plasticizers (trehalose and mannitol) which decreases Tg sufficiently to make the glass transition observable. Extrapolation to zero plasticizer concentration then yield the following Tg values: Tg (polyMe-β-CD)=317°C±5°C and Tg (polyβ-CD)=418°C±6°C.
ISSN:0144-8617
1879-1344
DOI:10.1016/j.carbpol.2016.04.032