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Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers
Published on: October 17, 2013
Design and process parameter evaluation of bilayer capsule systems for targeted ileal drug delivery
Elisa Millet1, Sofie S T Vandenbroucke2, Joseph P O'Shea3
1Capsugel France SAS, Colmar, France.
Summary
This study developed a novel bilayer capsule for targeted drug delivery to the distal small intestine. Optimized formulations demonstrated delayed release in the ileum, offering a promising platform for site-specific oral therapies.
Area of Science:
- Pharmaceutical Sciences
- Materials Science
- Drug Delivery
Background:
- Targeted drug delivery to the distal small intestine is challenging due to its dynamic nature.
- Developing effective drug delivery systems for the terminal ileum requires precise control over release kinetics.
Purpose of the Study:
- To engineer a bilayer capsule system for site-specific drug release in the terminal ileum.
- To investigate the impact of formulation and processing parameters on capsule performance.
Main Methods:
- Developed bilayer capsules with hydroxypropyl methylcellulose (HPMC) and pullulan inner layer, and ethylcellulose/sodium alginate outer layer.
- Systematically varied alginate concentration and curing conditions (temperature, RH).
- Characterized capsule morphology (SEM), surface properties, and functional performance (disintegration, dissolution) across simulated gastrointestinal pH.
Main Results:
- Alginate concentration influenced outer layer morphology and permeability; curing conditions affected film cohesion and porosity.
- Optimal formulations (4-6% alginate, cured at 70°C/40% RH) showed minimal water ingress in acidic conditions and delayed release at pH 7.4.
- Compared to reference capsules, developed systems exhibited a delayed release profile suitable for distal ileum targeting.
Conclusions:
- Capsule microstructure and performance are critically dependent on formulation and process parameters.
- The developed bilayer capsule system presents a robust platform for site-specific oral drug delivery to the distal small intestine.
- This approach offers potential for enhanced therapeutic efficacy through targeted drug release in the ileum.
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