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Title: Characterization of the copolymer poly(ethyleneglycol-g-vinylalcohol) as a potential carrier in the formulation of solid dispersions
Authors: Guns, Sandra
Kayaert, Pieterjan
Martens, Johan
Van Humbeeck, Jan
Mathot, Vincent
Pijpers, Thijs
Zhuravlev, Evgeni
Schick, Christophe
Van den Mooter, Guy # ×
Issue Date: Feb-2010
Publisher: Wissenschaftliche Verlagsgesellschaft
Series Title: European Journal of Pharmaceutics and Biopharmaceutics vol:74 issue:2 pages:239-247
Abstract: In order to fully exploit the graft copolymer poly(ethyleneglycol-g-vinylalcohol) (EG/VA) in the formulation of solid dispersions, a characterization of its phase behavior before, during and after spray-drying and hot-melt extrusion is performed. Solid state characterization was performed using MDSC and XRPD.
The effect of heating/cooling rate on the degree of crystallinity was studied using HPer DSC and ultra-fast
chip calorimetry. EG/VA consists of two semi-crystalline fractions, one corresponding to the polyethyleneglycol
(PEG) fraction (Tg = -57°C, Tm = 15°C) and one corresponding to the polyvinylalcohol (PVA)
fraction (Tg = 45°C, Tm = 212°C). XRPD analysis confirmed its semi-crystallinity, and EG/VA showed Bragg
reflections comparable to those of PVA. Spray-drying at a temperature lower than 170°C resulted in amorphization of the PVA fraction, while after hot-melt extrusion at different temperatures, the crystallinity of this fraction increases. In both cases, the PEG fraction is not influenced. Plasticization of the amorphous domains of the PEG or PVA fraction of the copolymer was dependent on the type and concentration of plasticizer, suggesting that also other small organic molecules like drugs may not homogeneously mix with both amorphous domains. A controlled cooling rate of 3000°C/s was necessary to make the copolymer completely amorphous.
ISSN: 0939-6411
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Drug Delivery and Disposition
Centre for Surface Chemistry and Catalysis
Physical Metallurgy and Materials Engineering Section (-)
× corresponding author
# (joint) last author

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