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Diclofenac salts, part 6: release from lipid microspheres
Adamo Fini1, Cristina Cavallari2, Antonio M Rabasco Alvarez3
1Department SMETEC, University of Bologna, Bologna 40127, Italy.
Journal of Pharmaceutical Sciences
|April 28, 2011
Summary
Diclofenac release from lipidic solid dispersions is significantly influenced by its chemical form and formulation. Drug release mechanisms shift from diffusion-controlled to diffusion/erosion-controlled with the addition of stearic acid.
Area of Science:
- Pharmaceutical Sciences
- Materials Science
Background:
- Diclofenac is a widely used non-steroidal anti-inflammatory drug (NSAID).
- Lipidic solid dispersions offer potential for controlled drug release applications.
- Understanding drug-carrier interactions is crucial for optimizing drug delivery systems.
Purpose of the Study:
- To investigate diclofenac release from lipidic solid dispersions.
- To evaluate the impact of different diclofenac chemical forms and lipid carriers on drug release.
- To explore the role of stearic acid in modifying drug release profiles.
Main Methods:
- Preparation of lipidic solid dispersions containing diclofenac (acid, sodium salt, pyrrolidine ethanol salt) with Compritol 888 ATO or Carnauba wax, with or without stearic acid.
- Microsphere fabrication using ultrasound-assisted atomization.
- Characterization using scanning electron microscopy, differential scanning calorimetry, and hot stage microscopy.
- In vitro drug release studies at varying pH levels.
Main Results:
- Formulation composition and diclofenac chemical form significantly affected drug release.
- Drug solubility in lipid mixtures followed the order: pyrrolidine ethanol salt > acid > sodium salt.
- System morphology ranged from matrix to microcapsule based on drug-carrier miscibility.
- Drug release was diffusion-controlled in pure lipid systems and diffusion/erosion-controlled in systems with stearic acid at pH 7.4.
Conclusions:
- The chemical form of diclofenac and formulation excipients critically determine drug release kinetics from lipidic solid dispersions.
- Stearic acid incorporation alters the release mechanism, suggesting a role in modulating drug diffusion and matrix erosion.
- These findings provide insights for designing advanced diclofenac delivery systems with tailored release profiles.
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