Drug diffusion and release from a bioerodible spherical capsule.

Area of Science:

• Biomedical Engineering
• Materials Science
• Pharmaceutical Sciences

Background:

• Controlled drug release is crucial for effective medical treatments.
• Bioerodible polymer capsules offer potential for optimized drug delivery.
• Modeling drug release from shrinking capsules is complex due to moving boundaries.

Purpose of the Study:

• To develop a theoretical model for drug release from a linearly eroding spherical capsule.
• To provide a closed-form solution for drug concentration and delivery characteristics.
• To understand the interplay between erosion and diffusion in drug delivery systems.

Main Methods:

• A mathematical transformation was employed to convert the moving boundary problem into a fixed boundary problem.
• A closed-form solution was derived for drug concentration distribution.
• The model was analyzed to understand the impact of diffusion coefficient and erosion rate.

Main Results:

• A single non-dimensional parameter governs drug release for uniform initial distribution.
• Drug release is determined by the balance between capsule erosion and drug diffusion.
• The theoretical model quantifies the influence of erosion rate and diffusion on drug delivery.

Conclusions:

• This work enhances the theoretical understanding of drug diffusion in bioerodible systems.
• The model accounts for practical erosion phenomena in drug delivery design.
• Findings can aid in the optimization of spherical polymer capsule-based drug delivery systems.