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09:39
Characterizing Dissipative Elastic Metamaterials Produced by Additive Manufacturing
Published on: June 28, 2024
Rheological modeling and torque-based processability prediction for celecoxib/PVPVA hot-melt extruded amorphous solid
Paula Kaufelde1, Rita Maria Soares1, Oxana Brante1
1Riga Stradins University, Latvia.
Summary
Melt viscosity predicts hot-melt extrusion torque for amorphous solid dispersions (ASDs). This viscosity-to-torque framework guides formulation selection and process optimization, ensuring drug stability and processability.
Area of Science:
- Pharmaceutical Sciences
- Materials Science
- Chemical Engineering
Background:
- Predicting amorphous solid dispersion (ASD) processability during hot-melt extrusion (HME) is crucial for pharmaceutical development.
- Understanding the relationship between material properties and process parameters is key to successful HME formulation.
Purpose of the Study:
- To demonstrate that melt apparent viscosity data from rotational rheology, combined with constitutive modeling, can predict in-process extruder torque for ASDs.
- To guide formulation and process selection for HME using a viscosity-to-torque framework.
Main Methods:
- Quantified composition- and temperature-dependent melt rheology of celecoxib-PVPVA 64 ASDs at various drug-to-polymer ratios (30/70, 50/50, 70/30 w/w) between 130-160°C.
- Fitted steady-shear viscosity data to Cross and Carreau models and extrapolated to process-relevant shear rates.
- Converted extrapolated viscosities to torque using shear stress relationships and applied empirical calibration for HME conditions.
Main Results:
- Polymer-rich formulations (30/70) exhibited higher viscosity and torque demand, while drug-rich systems (70/30) showed lower viscosity due to plasticization, impacting the amorphous processing window.
- The Cross model provided superior viscosity fits and torque predictions compared to the Carreau model.
- Transparent filaments confirmed amorphization for 30/70 and 50/50 formulations; 70/30 showed heterogeneity. The 30:70 formulation at 150°C offered the best balance of properties.
Conclusions:
- The viscosity-to-torque framework provides a material-sparing approach to anticipate HME processability for ASDs.
- This method aids in defining composition- and temperature-dependent processing windows, optimizing formulation and process selection.
- The study identified the 30:70 celecoxib-PVPVA ASD at 150°C as the optimal condition for VCM preparation, balancing dispersion, amorphization, and processability.
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