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Constant-rate drug release from novel anionic gel beads with transient composite structure
1Faculty of Pharmacy, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Ontario, Canada.
Journal of Pharmaceutical Sciences
|September 1, 1993
Summary
A novel anionic composite bead system offers prolonged, constant-rate drug release. This system utilizes a transient membrane-matrix structure for sustained drug delivery, avoiding prolonged release tailing.
Area of Science:
- Polymer science and materials engineering
- Pharmaceutical sciences and drug delivery
Background:
- Developing advanced drug delivery systems is crucial for improving therapeutic efficacy and patient compliance.
- Constant-rate drug release is highly desirable for maintaining therapeutic drug concentrations and minimizing side effects.
- Existing membrane-matrix systems often suffer from prolonged drug release tailing, complicating dosage regimens.
Purpose of the Study:
- To develop a novel anionic composite bead system for prolonged constant-rate drug release.
- To investigate the drug-polymer complex formation and its impact on drug loading.
- To characterize the transient membrane-matrix structure and its role in controlling drug release kinetics.
Main Methods:
- Suspension polymerization of poly(methyl methacrylate-co-methacrylic acid) (PMMA/MAA) to create composite beads.
- Fabrication of beads with a PMMA/MAA surface layer and a PMMA/MANa core.
- High drug loading of oxprenolol HCl and analysis of drug-polymer complex formation.
- In vitro drug release studies to evaluate release profiles and kinetics.
Main Results:
- Achieved high drug loading (>20%) of oxprenolol HCl with a low loading solution concentration (0.5%), suggesting ionic salt complex formation.
- Observed an initial burst release followed by an extended constant-rate release region.
- Demonstrated that the transiently ionizing PMMA/MAA surface layer acts as a rate-controlling membrane for an extended period.
- The system avoids prolonged drug release tailing, a common issue with permanent membrane-matrix systems.
Conclusions:
- The developed anionic composite bead system effectively achieves high drug loading and prolonged constant-rate drug release.
- The transient nature of the rate-controlling surface layer is key to sustained release and avoiding release tailing.
- This system represents a significant advancement in drug delivery, offering potential for improved therapeutic outcomes.