Drug delivery from microcapsules: How can we estimate the release time?

Area of Science:

• Pharmaceutics and Biomedical Science
• Chemical Engineering
• Materials Science

Background:

• Accurate prediction of drug release kinetics is crucial for developing effective drug delivery systems.
• Composite spherical microcapsules are widely used for controlled drug release applications.
• Understanding the factors influencing drug depletion time is essential for optimizing therapeutic outcomes.

Purpose of the Study:

• To develop and validate two novel methods for estimating drug release time from multi-layer composite spherical microcapsules.
• To utilize temporal moments of drug concentration for efficient prediction of drug depletion.
• To provide computationally inexpensive tools for quantifying release performance in microcapsule drug delivery.

Main Methods:

• Development of a multi-layer diffusion model for drug release from composite spherical microcapsules.
• Application of two distinct approaches based on temporal moments (zeroth, first, and higher-order) of drug concentration.
• Exact computation of temporal moments without requiring the full transient solution of the diffusion model.

Main Results:

• The first approach provides a simple algebraic approximation of release time using zeroth and first temporal moments.
• The second approach offers an asymptotic estimate of release time dependent on higher-order temporal moments.
• Both methods were validated through several test cases, demonstrating their utility and computational efficiency.

Conclusions:

• The proposed methods offer a computationally cheap and effective means to estimate drug release time from composite microcapsules.
• Temporal moments provide valuable insights into the timescale of drug release processes.
• These approaches can aid in the design and optimization of microcapsule-based drug delivery systems.