Modeling of diffusion with partitioning in stratum corneum using a finite element model

Area of Science:

• Dermatology
• Biophysics
• Computational modeling

Background:

• Understanding chemical transport in the skin is crucial for transdermal drug delivery and risk assessment.
• The stratum corneum (SC), skin's outer layer, presents a complex composite structure affecting chemical diffusion.
• Accurate modeling of diffusion and partitioning is needed for predicting chemical behavior in the skin.

Purpose of the Study:

• To develop and validate a finite element method model for chemical diffusion and partitioning in the stratum corneum.
• To investigate the influence of the partition coefficient on diffusion in simplified and realistic SC geometries.
• To provide a flexible computational tool for analyzing transdermal penetration and disposition.

Main Methods:

• Utilized a finite element method (FEM) with thermal analysis capabilities to model 2D diffusion in the SC.
• Incorporated different diffusivity values for SC components and partition coefficients at interfaces.
• Validated the FEM model against analytical solutions for flux, concentration profiles, and time lag.

Main Results:

• The FEM model successfully simulated diffusion with partitioning in both simplified 'brick and mortar' and irregular SC geometries.
• Model results were validated against analytical solutions, demonstrating accuracy in predicting diffusion parameters.
• The study explored the impact of partition coefficients on diffusion dynamics in SC models.

Conclusions:

• The finite element method provides a flexible and accurate approach for modeling chemical diffusion and partitioning in the stratum corneum.
• This modeling technique can be applied to diverse SC structures, including irregular geometries derived from imaging.
• The validated model serves as a valuable tool for research in transdermal delivery and chemical risk assessment.