The Combined Diffusion and Adsorption Concept for Prediction of Nanoparticles Transport through Dermal Layers Based on Experiments in Membranes.

The non-invasive introduction of active substances into the human body is a top challenge for researchers in medicine, pharmacology, and cosmetology. Development of nanotechnology and possibilities of creating more and more complex drug carriers on a nanoscale give a more realistic prospect of meeting this challenge. However, in the absence of sufficient knowledge of the mechanisms of such systems' transport through the human skin structure, it is necessary to look deeper into these issues. There are several models describing nanoparticles transport through the skin, but they are mainly based on diffusion process analysis. In this work, a model was proposed to predict nanoparticles transport through the skin, based on the combined diffusion and adsorption concept. This approach was based on experimental studies of silver and copper nanoparticles' diffusion process through different filtration membrane layers. Dependence of the degree of adsorption on the surface parameter was described using modified Langmuir equation. Then, these considerations were related to the structure of the stratum corneum, which made it possible to predict the changes in the mass of penetrating nanoparticles as a function of transport path length. A discussion of the presented model, depending on such parameters as nanoparticle size, skin cell thickness, or viscosity of the "intercellular cement", was also performed.