Computer Simulation of Skin Permeability of Hydrophobic and Hydrophilic Chemicals – Influence of Follicular Pathway

Modeling the Percutaneous Absorption of Solvent-deposited Solids Over a Wide Dose Range

“…The dermal absorption model employed builds on a simpler model recently developed by our group to simulate the skin permeability of hydrophobic and hydrophilic chemicals 4 and called therein Model 2. Model 2 is a one-dimensional, transient diffusion/evaporation code built on the gPROMS platform incorporating a vehicle layer, three skin layers and a follicular diffusion pathway.…”

“…Its steady state properties have been thoroughly explored. 3,4 In this section we describe elaborations on Model 2 designed to yield more accurate simulations of transient diffusion associated with solvent-deposited solids. The revised model (Model 3) has the following new features:…”

“…The base of the infundibulum is impermeable in the present simulations, but a fraction of "open" follicles can be included in the model. 4 The dashed red rectangle identifies the ORS region.…”

“…Most recently we have incorporated a polar pathway for hydrophilic permeants into the model and moved it to a process engineering platform, gPROMS Ò . 3,4 In the present analysis we extend the model to accurately simulate a solvent deposition process in which a solid precipitate may form on the skin surface as the solvent evaporates. The disposition of both components is tracked.…”

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The transient absorption of two skin care agents, niacinamide (nicotinamide, NA) and methyl nicotinate (MN), solvent-deposited on ex vivo human skin mounted in Franz diffusion cells has been analyzed according to a new variation on a recently published mechanistic skin permeability model (Yu et al 2020. J Pharm Sci 110:2149.

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