What is the Origin of Stratum Corneum Permeability?

This term is fundamental to dermatological and pharmaceutical science, rooted in the application of Fick's laws of diffusion to biological membranes. Early research focused intensely on quantifying the permeability coefficient for various molecules to accurately predict their systemic uptake. The stratum corneum is universally recognized as the principal rate-limiting barrier for the majority of non-invasive drug delivery systems.

What is the Mechanism of Stratum Corneum Permeability?

Permeability is fundamentally governed by the highly ordered structural organization of the intercellular lipid matrix and the specific physicochemical properties of the diffusing drug molecule, including its molecular weight and overall lipophilicity. Any damage, disruption, or temporary fluidization of the lipid lamellae increases permeability, while factors like skin hydration can also substantially modulate the barrier function. Pharmaceutical interventions are designed to safely and reversibly increase this permeability to facilitate therapeutic flux.

Stratum Corneum Permeability ∞ Area

Stratum Corneum Permeability

Meaning

The intrinsic capacity of the skin’s outermost layer, the stratum corneum, to permit or restrict the passage of chemical substances across its structure. This permeability is the most significant physiological determinant of the rate and extent of transdermal drug absorption and is inversely proportional to the layer’s effectiveness as a protective barrier. Clinically, variations in stratum corneum permeability significantly impact the necessary dosing and formulation requirements for transdermal hormonal therapies.