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Rheological characterization of polymeric solutions used in spray drying process
Tiago Porfirio1, Francisco J Galindo-Rosales2, Laura Campo-Deaño3
1Hovione Farmaciência SA, Estrada do Paço do Lumiar, 1649-038 Lisbon, Portugal; LAETA, IDMEC, Mechanical Engineering Department, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal.
This study characterizes polymers like HPMC and Eudragit for spray drying. Understanding their rheology, including viscosity and elasticity, aids in optimizing amorphous solid dispersion formulation and process development.
Area of Science:
- Materials Science
- Chemical Engineering
- Pharmaceutics
Background:
- Amorphous solid dispersions (ASDs) enhance drug solubility and bioavailability.
- Spray drying is a key technique for ASD formulation.
- Rheological properties of polymers are critical for successful spray drying.
Purpose of the Study:
- To rheologically characterize common polymers used in spray-dried ASDs.
- To understand the fluid behavior of polymer solutions under different flow conditions.
- To provide data supporting spray drying process optimization.
Main Methods:
- Rheological characterization of polymer solutions (copovidone, HPMC, HPMCAS, Eudragit L100).
- Measurement of surface tension, shear viscosity, and relaxation time.
- Assessment of fluid behavior under shear and extensional flow.
Main Results:
- HPMC and HPMCAS solutions showed shear-thinning behavior.
- Eudragit L100 solutions behaved as Boger fluids (constant viscosity, viscoelastic).
- Copovidone exhibited Newtonian fluid behavior without elasticity.
- Polymer solutions displayed viscoelasticity and concentration-dependent relaxation times under extensional flow.
Conclusions:
- The rheological data provides fundamental insights into polymer solution behavior during spray drying.
- Understanding these properties can improve atomization modeling.
- This characterization supports and accelerates the development of spray drying processes for ASDs.
