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Updated: Jul 7, 2026
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Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles
Published on: August 28, 2015
In vitro controlled drug release from loaded microspheres--dose regulation through formulation
Laura Jane Waters1, Evangelos Pavlakis
1Division of Pharmacy and Pharmaceutical Sciences, University of Huddersfield, Queensgate, Huddersfield, UK.
Summary
Controlled ibuprofen release was achieved using specific microsphere formulations and buffer solutions. The buffer anion appears to stabilize the ibuprofen-microsphere matrix, influencing drug release rates in vitro.
Area of Science:
- Pharmaceutical Sciences
- Drug Delivery Systems
- Materials Science
Background:
- Microspheres offer potential for controlled drug release.
- Understanding factors influencing drug release kinetics is crucial for formulation development.
Purpose of the Study:
- To investigate the impact of microsphere composition and dissolution buffer media on ibuprofen release profiles.
- To determine if controlled drug release from ibuprofen-loaded microspheres is achievable.
Main Methods:
- Ibuprofen was encapsulated in fatty acid microspheres (80-125 µm diameter, 3:1 excipient to ibuprofen ratio).
- Drug release was assessed for stearic acid and cetostearyl alcohol microspheres compared to free ibuprofen.
- Release profiles were evaluated in five different buffer media (sodium phosphate, potassium phosphate, citric acid and phosphate mix, MOPS, tris).
Main Results:
- Cetostearyl alcohol microspheres significantly retarded ibuprofen release compared to stearic acid microspheres and free ibuprofen.
- Significant differences in ibuprofen release rates and extents were observed across the tested buffer media.
- These buffer-dependent release differences were independent of pH, temperature, buffer concentration, and cation type.
Conclusions:
- Both microsphere formulation and dissolution buffer choice significantly influence in vitro ibuprofen release.
- Controlled drug release is achievable by selecting appropriate microsphere types and buffer solutions.
- Buffer anions are hypothesized to stabilize the ibuprofen-microsphere matrix, thereby controlling drug release.
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