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Microstructure of an immiscible polymer blend and its stabilization effect on amorphous solid dispersions
Ziyi Yang1, Kathrin Nollenberger, Jessica Albers
1School of Pharmacy, University of East Anglia, Norwich, Norfolk, U.K., NR4 7TJ.
Molecular Pharmaceutics
|May 15, 2013
Summary
Utilizing immiscible polymer blends enhances drug stabilization and solubility for amorphous molecular dispersions. This phase separation approach protects poorly soluble drugs from recrystallization, improving drug release and formulation stability.
Area of Science:
- Materials Science
- Pharmaceutical Technology
- Polymer Chemistry
Background:
- Amorphous molecular dispersions are crucial for poorly soluble drugs.
- Stabilization and solubilization of these dispersions remain formulation challenges.
- Polymer blends offer potential for improved drug delivery systems.
Purpose of the Study:
- To investigate the use of immiscible polymer blend phase separation for stabilizing amorphous drug dispersions.
- To optimize drug loading and stabilization of poorly soluble drugs using this approach.
- To evaluate the performance of polymer blend formulations compared to binary systems.
Main Methods:
- Hot melt extrusion to load felodipine into a EUDRAGIT E PO-PVP-VA polymer blend.
- Characterization using modulated differential scanning calorimetry (mDSC), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and atomic force microscopy (AFM).
- Assessment of drug release, and stabilization against temperature, humidity, and mechanical stress.
Main Results:
- Polymer blend formulations exhibited superior drug release compared to binary systems.
- Enhanced stabilization against stressed temperature, humidity, and mechanical milling was observed.
- Phase-separated microstructure with hydrophilic domains hosting molecularly dispersed drug, protected by hydrophobic domains, was identified.
Conclusions:
- Immiscible polymer blend phase separation is an effective strategy for stabilizing amorphous molecular dispersions.
- The unique microstructure prevents drug recrystallization, improving stability and drug release.
- This formulation approach holds promise for enhancing the delivery of poorly soluble drugs.
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