Diffusion of uncharged solutes through human nail plate

Area of Science:

• Pharmacokinetics and Biomechanics
• Materials Science and Engineering

Background:

• Understanding solute diffusion in the human nail plate is crucial for effective transungual drug delivery.
• Current models for diffusion in dense keratin matrices do not fully capture nail plate's complex microstructure.

Purpose of the Study:

• To compare passive diffusion data in hydrated human nail plates with predictions from two established theories.
• To identify limitations in existing theories and experimental approaches for nail plate diffusion.

Main Methods:

• Collection of passive diffusion data for uncharged solutes in hydrated human nail plate.
• Comparison of experimental data with theoretical predictions for diffusion in dense keratin matrices.

Main Results:

• Quantitative agreement between experimental nail permeability data and theoretical predictions was poor.
• Limitations were identified in both experimental methodologies and theoretical extrapolation procedures.

Conclusions:

• The microstructure of the human nail plate is more complex than current models assume, potentially influenced by residual lipids.
• Further rigorous experimentation and theoretical analysis are needed to improve models of nail plate mass transport and transungual drug delivery.
• Hydrated nail plate may serve as a model for stratum corneum, advancing skin permeability research.