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Effects of phase separating systems on lyophilized hemoglobin
M C Heller1, J F Carpenter, T W Randolph
1Department of Chemical Engineering, University of Colorado, Boulder 80309-0424, USA.
Journal of Pharmaceutical Sciences
|December 1, 1996
Summary
Polymer systems protect proteins during freezing via preferential exclusion, but phase separation during lyophilization can harm protein stability. Freezing and drying protection mechanisms differ.
Area of Science:
- Biochemistry
- Polymer Science
- Biophysical Chemistry
Background:
- Polymer liquid-liquid two-phase systems are valuable for studying protein stabilization mechanisms.
- Understanding protein behavior during freezing and freeze-drying is crucial for biopharmaceutical development.
Purpose of the Study:
- To investigate protein structural integrity during freezing and lyophilization within polymer two-phase systems.
- To elucidate the distinct mechanisms of protein protection during freezing versus lyophilization.
Main Methods:
- Utilized Fourier transform infrared spectroscopy to monitor the structural integrity of recombinant hemoglobin.
- Employed polyethylene glycol (PEG)-dextran systems to create biphasic environments for protein analysis.
Main Results:
- Proteins in different phases of the PEG-dextran system showed similar protection against freezing stresses.
- Significant differences in polymer-induced protein protection were observed during lyophilization.
- Evidence suggests that phase separation during lyophilization can negatively impact protein structural stability.
Conclusions:
- Protein protection during freezing in polymer systems is primarily mediated by preferential exclusion.
- The mechanisms safeguarding proteins during freezing and lyophilization are fundamentally distinct.
- In-situ phase separation during freeze-drying poses a risk to protein structural integrity.