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Spray-drying of trypsin - surface characterisation and activity preservation
A Millqvist-Fureby1, M Malmsten, B Bergenståhl
1Institute for Surface Chemistry, P.O. Box 5607, SE-114 86, Stockholm, Sweden. anna.fureby@surfchem.kth.se
International Journal of Pharmaceutics
|October 16, 1999
Summary
Spray-drying trypsin with carbohydrates showed high enzyme activity (≥82%). Trypsin concentrated on particle surfaces, with activity loss linked to surface adsorption and other factors.
Area of Science:
- Biochemistry
- Materials Science
- Chemical Engineering
Background:
- Enzyme stability during drying is crucial for applications.
- Spray-drying is a common method for enzyme powder production.
- Understanding protein-excipient interactions is key to preserving enzyme activity.
Purpose of the Study:
- To investigate the impact of spray-drying on trypsin activity.
- To analyze the interaction between trypsin and powder particle surfaces.
- To explore methods for controlling trypsin surface concentration during spray-drying.
Main Methods:
- Spray-drying of trypsin with various carbohydrates (lactose, sucrose, mannitol, alpha-cyclodextrin, dextrin).
- Quantification of trypsin surface coverage on powder particles.
- Assessment of residual trypsin activity in dried powders.
- Evaluation of surfactant effects on surface protein concentration.
Main Results:
- Trypsin was significantly enriched at the surface of spray-dried particles (10-65% coverage).
- Surface coverage was dependent on the initial trypsin concentration.
- Adding surfactants reduced trypsin surface concentration.
- Residual trypsin activity was generally high (≥82%), with losses partly attributed to surface inactivation.
Conclusions:
- Spray-drying leads to significant trypsin adsorption at the air-liquid interface, which persists post-drying.
- Surfactants can modulate trypsin surface concentration.
- While surface inactivation contributes to activity loss, other mechanisms are involved, particularly with mannitol and sucrose.