The Use of Binary Polymeric Networks in Stabilizing Polyethylene Oxide Solid Dispersions

Area of Science:

• Materials Science
• Polymer Chemistry
• Pharmaceutical Technology

Background:

• Amorphous solid dispersions are crucial for enhancing drug solubility and bioavailability.
• Polyethylene oxide (PEO) is a common polymer used in drug formulations but can exhibit poor physical stability.
• Stabilizing amorphous PEO is essential for maintaining drug efficacy in solid dispersion systems.

Purpose of the Study:

• To evaluate Eudragit S100 as a high Tg polymer for stabilizing amorphous polyethylene oxide (PEO).
• To investigate the miscibility and inter-polymer interactions between PEO and Eudragit S100.
• To assess the stability of celecoxib (CX) in PEO/Eudragit S100 amorphous solid dispersions.

Main Methods:

• Hot-melt extrusion was used to prepare PEO/Eudragit S100 blends and CX/PEO/S100 ternary mixtures.
• Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) assessed polymer miscibility.
• Powder X-ray diffractometry (PXRD) confirmed the amorphous state of celecoxib.
• Fourier transform infrared (FTIR) spectroscopy investigated inter-polymer interactions.

Main Results:

• PEO and Eudragit S100 showed good miscibility, particularly at a 50:50 wt/wt ratio.
• Celecoxib was successfully amorphized in the ternary mixtures, indicated by the absence of crystalline peaks.
• The 50:50 PEO/S100 formulation exhibited the highest stability under accelerated storage conditions (40°C/75% RH).
• Anti-plasticization was observed, with a single Tg increasing with higher Eudragit S100 content.

Conclusions:

• Eudragit S100 effectively stabilizes amorphous polyethylene oxide (PEO) in solid dispersions.
• Hydrogen bonding between Eudragit S100 and PEO is the primary mechanism for stabilizing the amorphous celecoxib (CX) system.
• The 50:50 PEO/S100 ratio provides optimal physical stability for amorphous drug formulations.