Selection of Solid-State Plasticizers as Processing Aids for Hot-Melt Extrusion.

Area of Science:

• Pharmaceutical Science
• Materials Science
• Chemical Engineering

Background:

• Hot-melt extrusion (HME) is a key pharmaceutical manufacturing process requiring optimized processing aids.
• Selection of appropriate plasticizers is crucial for enhancing the processability and final product properties in HME.

Purpose of the Study:

• To identify and evaluate solid-state plasticizers for the hot-melt extrusion (HME) process.
• To assess the effectiveness of selected plasticizers as processing aids in binary and ternary systems.

Main Methods:

• Utilized solubility parameters, thermal analysis (DSC, TGA), and rheological evaluation to assess plasticizer performance.
• Investigated binary (polymer:plasticizer) and ternary (API:polymer:plasticizer) systems using Indomethacin and Eudragit® E PO as models.
• Developed an empirical model correlating physical mixture rheology to HME process outcomes.

Main Results:

• Stearic acid, glyceryl behenate, and polyethylene glycol 8000 were identified as suitable solid-state plasticizers based on solubility parameters.
• Thermal and rheological assessments confirmed miscibility predictions and provided insights into plasticization efficiency.
• The developed model successfully correlated rheological properties with HME process performance.

Conclusions:

• Solid-state plasticizers like stearic acid, glyceryl behenate, and PEG 8000 can significantly improve HME processability.
• Understanding the thermal and rheological behavior of mixtures is vital for selecting optimal plasticizers and processing conditions.
• This study provides a framework for selecting solid plasticizers and optimizing HME processes for pharmaceutical applications.