Lateral Transport During Membrane Permeation in Diffusion Cell: In Silico Study on Edge Effect and Membrane Blocking

Area of Science:

• Pharmacokinetics and Drug Delivery
• Biomaterials Science
• Transport Phenomena

Background:

• Membrane transport studies using diffusion cells often assume one-dimensional flux.
• Lateral diffusion within the membrane can lead to edge effects and influence permeation.
• Understanding these non-ideal transport phenomena is crucial for accurate permeability assessments.

Purpose of the Study:

• To investigate the impact of lateral transport on permeation across two-layer membranes in diffusion cells.
• To analyze the effects of edge conditions and partial membrane blocking on flux.
• To evaluate the significance of lateral diffusion in gingiva and skin permeation models.

Main Methods:

• Utilized COMSOL Multiphysics for time-dependent and steady-state transport simulations.
• Modeled permeation across a two-layer membrane system.
• Simulated scenarios including edge effects and partial membrane blockage.

Main Results:

• Edge effects were found to increase steady-state flux by up to 35% in specific configurations (thick membrane, small opening).
• The magnitude of the edge effect diminished with decreased membrane thickness and top-layer permeability.
• Lateral diffusion significantly reduced the impact of membrane blocking, mitigating flux reduction by over 50% when the object was in the receptor.

Conclusions:

• Lateral transport phenomena, including edge effects and lateral diffusion, are significant in diffusion cell studies.
• These effects can alter measured permeation rates and should be considered in the design and interpretation of membrane transport experiments.
• Accounting for lateral transport is essential for accurate modeling of drug permeation through biological barriers like skin and gingiva.