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In vitro and in vivo degradation studies for development of a biodegradable patch based on poly(3-hydroxybutyrate)
Thomas Freier1, Carmen Kunze, Claudia Nischan
1Institute for Biomedical Engineering, University of Rostock, Germany. thomas.freier@chemie.uni-rostock.de
Biomaterials
|June 13, 2002
Summary
This study investigated resorbable gastrointestinal patches made from poly(3-hydroxybutyrate) (PHB). PHB blends demonstrated suitable degradation for bowel defect repair in rats, showing complete resorption within 26 weeks.
Area of Science:
- Biomaterials Science
- Gastroenterology
- Polymer Chemistry
Background:
- Developing resorbable materials for gastrointestinal (GI) patches is crucial for effective bowel defect repair.
- Poly(3-hydroxybutyrate) (PHB) and poly(L-lactide) (PLLA) are candidate polymers for such applications.
- Understanding polymer degradation kinetics in the GI environment is essential for material selection.
Purpose of the Study:
- To evaluate the in vitro degradation of poly(3-hydroxybutyrate) (PHB) films and modified PHB formulations.
- To assess the influence of blending, additives, and enzymatic activity on PHB degradation rates.
- To determine the in vivo performance of a selected PHB-based patch for bowel defect repair in rats.
Main Methods:
- Solution-cast films of PHB, modified PHB, and PLLA were subjected to in vitro degradation studies in buffer solutions (pH 7.4, 37°C).
- Molecular weight changes were monitored over one year.
- In vitro enzymatic degradation tests were performed using pancreatin.
- A PHB/atactic PHB blend patch was fabricated and implanted in Wistar rats to repair bowel defects.
Main Results:
- Pure PHB molecular weight halved after one year; blending with atactic PHB accelerated degradation.
- Hydrophobic plasticizers decelerated PHB degradation, while water-soluble additives slightly accelerated it.
- Pancreatin significantly accelerated PHB degradation (threefold compared to hydrolysis), while PLLA remained largely unaffected.
- In vivo, PHB/atactic PHB patches showed material remnants in only one of four rats after 26 weeks, with successful closure of bowel defects.
Conclusions:
- PHB-based materials, particularly PHB/atactic PHB blends, exhibit tunable degradation profiles suitable for gastrointestinal applications.
- The selected PHB patch demonstrated adequate resistance to intestinal secretions and complete in vivo resorption within 26 weeks.
- PHB-based patches are a promising resorbable option for repairing gastrointestinal defects.