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Characterization of frozen glucose solutions
L S Taylor1, P York, A C Williams
1Postgraduate Studies in Pharmaceutical Technology, School of Pharmacy, University of Bradford, West Yorkshire, United Kingdom.
Pharmaceutical Development and Technology
|April 29, 1998
Summary
Freezing nonequilibrated glucose solutions preserves anomer forms, impacting freeze-dried product properties. This study reveals how freezing affects glucose anomers and formulation stability.
Area of Science:
- Pharmaceutical Sciences
- Physical Chemistry
- Spectroscopy
Background:
- Reducing sugars are utilized as additives in freeze-dried formulations.
- Understanding the physical state of sugars post-freezing is crucial for formulation stability.
Purpose of the Study:
- To investigate the impact of freezing on nonequilibrated glucose solutions.
- To analyze the anomeric state of glucose after freezing using FT-Raman spectroscopy.
Main Methods:
- Preparation of glucose solutions from alpha- or beta-crystalline forms.
- Freezing solutions at varying times post-dissolution.
- Analysis using FT-Raman spectroscopy to identify anomers.
Main Results:
- Solutions frozen immediately retained the anomeric signature of the parent crystalline form.
- Pre-freezing equilibration (24 hours) resulted in the presence of both anomers.
- Frozen nonequilibrated solutions exhibited distinct properties, with beta-glucose solutions showing a lower glass transition temperature.
Conclusions:
- Freezing effectively halts glucose anomer interconversion in nonequilibrated solutions.
- The anomeric composition of frozen glucose solutions influences their physical properties.
- Variations in freeze-dried formulation properties may arise from freezing nonequilibrated reducing sugar solutions.