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Sugar-polymer hydrogen bond interactions in lyophilized amorphous mixtures
1School of Pharmacy, University of Wisconsin-Madison, 53706, USA.
Journal of Pharmaceutical Sciences
|April 3, 1999
Summary
This study shows sucrose forms stronger hydrogen bonds with poly(vinylpyrrolidone) (PVP) than other sugars in amorphous solid solutions. This interaction influences the material's glass transition temperature (Tg).
Area of Science:
- Materials Science
- Polymer Chemistry
- Physical Chemistry
Background:
- Amorphous solid solutions are crucial in pharmaceuticals and food science.
- Understanding molecular interactions, like hydrogen bonding, is key to controlling material properties.
- Poly(vinylpyrrolidone) (PVP) is a model polymer used to study these interactions.
Purpose of the Study:
- To investigate hydrogen bonding between various glass-forming sugars and PVP in lyophilized amorphous solid solutions.
- To correlate hydrogen bonding extent with the glass transition temperature (Tg) of the sugar-PVP mixtures.
Main Methods:
- Preparation of binary amorphous solid solutions using lyophilization.
- Differential scanning calorimetry (DSC) to measure glass transition temperatures (Tg).
- Fourier Transform Raman (FT-Raman) spectroscopy to monitor hydrogen bonding interactions.
Main Results:
- Sucrose exhibited stronger hydrogen bonding with PVP compared to other disaccharides (trehalose) and trisaccharides (raffinose).
- Maltodextrins showed reduced hydrogen bonding with PVP relative to lower molecular weight sugars.
- A significant inverse correlation was observed between the extent of hydrogen bonding and the sugar's Tg.
Conclusions:
- Hydrogen bonding plays a critical role in the thermodynamics of mixing in amorphous solid systems.
- The strength of sugar-PVP hydrogen bonds influences the overall stability and Tg of the amorphous solid solutions.
- Sucrose's strong interactions suggest potential for enhanced stabilization in formulations.