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Degradable polyphosphazene/poly(alpha-hydroxyester) blends: degradation studies
Archel M A Ambrosio1, Harry R Allcock, Dhirendra S Katti
1Department of Chemical Engineering, Center for Advanced Biomaterials and Tissue Engineering, Drexel University, Philadelphia, PA 19104, USA.
Biomaterials
|April 2, 2002
Summary
A novel polyphosphazene/poly(alpha-hydroxyester) blend offers improved biomaterial performance by neutralizing acidic degradation products, unlike traditional polymers like poly(lactide-co-glycolide) (PLAGA). This blend shows potential for safer, long-term implantable medical devices.
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Biomedical Engineering
Background:
- Polymers of lactic acid and glycolic acid are widely used in biomedical applications but release acidic byproducts.
- These acidic degradation products raise concerns for long-term implantable devices.
Purpose of the Study:
- To design and evaluate a novel biodegradable polyphosphazene/poly(alpha-hydroxyester) blend.
- To assess if the blend mitigates the acidic degradation issues associated with poly(alpha-hydroxyesters).
Main Methods:
- Prepared a blend of poly(lactide-co-glycolide) (50:50 PLAGA) and poly[(50% ethyl glycinato)(50% p-methylphenoxy) phosphazene] (PPHOS-EG50).
- Degraded circular matrices of the blend and parent polymers in non-buffered solutions (pH 7.4).
- Quantified degradation by measuring mass loss, molecular weight changes, and acid released, using neutralizing base to maintain neutral pH.
Main Results:
- The PLAGA-PPHOS-EG50 blend required significantly less neutralizing base to maintain a neutral pH compared to PLAGA alone.
- The blend exhibited an intermediate degradation rate between the parent polymers.
- Polyphosphazene degradation products effectively neutralized the acidic products from PLAGA.
Conclusions:
- The PLAGA-PPHOS-EG50 blend demonstrates reduced acidity during degradation.
- This blend offers a potential improvement over existing poly(alpha-hydroxyester) biomaterials for long-term applications.
- The findings suggest a viable new option for biodegradable implantable devices.