Slow release from a coated sphere with a slightly deformed coating

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Chemical Engineering

Background:

• Controlled drug delivery systems rely on precise coating formulations.
• Coating film integrity is crucial for predictable drug release kinetics.
• Particle shape deviations can alter drug diffusion and release patterns.

Purpose of the Study:

• To theoretically investigate the impact of slight coating film deformation on drug concentration distribution.
• To analyze how coating shape deformation affects slow drug release characteristics from coated particles.
• To quantify the influence of deformation parameters on drug release profiles.

Main Methods:

• A perturbation technique was used to simplify the deformed spherical problem.
• The problem was transformed into a series of concentric spherical problems.
• Governing equations were solved analytically with a restricted deformation shape function.

Main Results:

• Slight coating deformation has a secondary effect on average drug release rates.
• Significant effects on concentration profiles and release rates are observed with larger deformations.
• Low drug diffusivity in the coating film amplifies the impact of shape deformation.

Conclusions:

• Coating shape deformation is a secondary factor for average release rates with slight deformations.
• Non-slight deformations significantly influence drug release, particularly with low drug diffusivity.
• Understanding deformation effects is critical for optimizing drug delivery system performance.