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How twin-screw extrusion works
Twin-screw extrusion (TSE) applies thermal and mechanical energy to transform crystalline APIs into amorphous forms. The process involves feeding the API with a carrier like mesoporous silica into a rotating twin-screw barrel, which then heats, shears, and disperses the material into a stable amorphous state. This solvent-free method allows for continuous production with scalable parameters.
The role of mesoporous silica
Developed through a collaboration with W.R. Grace & Co., mesoporous silica provides a high-surface-area carrier that stabilizes APIs in their amorphous form. The API is mechanically embedded within the silica's pores, reducing the risk of recrystallization and enhancing physical stability. This process is compatible with thermal extrusion, enabling solvent-free processing even for heat-sensitive compounds when run at optimized conditions.
What is SME and why does it matter?
This graph illustrates how Specific Mechanical Energy (SME) reduces API crystallinity to 44% at 25°C, enhancing amorphization and solubility—even before heat application. Source: Richter et al. (2024), Pharmaceutics, 16, 1368.
Specific mechanical energy (SME) is a measure of the mechanical input delivered to the formulation during extrusion. It reflects the combination of torque, screw speed, and material throughput. SME is directly correlated with the degree of amorphization: more energy typically increases the amount of transformation from crystalline to amorphous.
- Higher SME often leads to higher amorphous content
- Tuning of SME can be based on API and excipient properties
- Effective energy input can be measured and adjusted via process analytics
Inside the extrusion line
The TSE line includes multiple heating zones, torque measurement capabilities, screw elements for mixing and conveying, and modular feeders. These elements allow precise control over temperature, shear, and residence time.
Supporting your success from lab to line, Thermo Fisher Scientific offers scalable technology, expert guidance, and comprehensive resources to support dry amorphization
Ready to Analyze and Scale? You’ve seen how twin-screw extrusion works. Next, learn how to confirm amorphization and analyze formulation stability in Module 3.
For Research Use Only. Not for use in diagnostic procedures.