Biomaterial Database

[Estimation of skin absorption of chemicals with Fick's diffusion model]. 2022

Hiroaki Todo

Faculty of Pharmacy and Pharmaceutical Sciences, Josai University.

The skin is not only the site of drug application, but also the site of exposure to various chemical substances. Prediction of skin permeability, body absorption, and local skin concentration of chemicals are very important to assure efficacy and safety. Most in silico models for skin permeation of chemical are based on the prediction of its permeability coefficient (P, unit cm/s), and a certain level of prediction accuracy has been obtained. On the other hand, the amount absorbed in the body of a chemical is calculated from the sum of the amount of skin permeation and the amount under the stratum corneum (viable epidermis and dermis). The amount of skin permeation can be calculated from the P value as mentioned above, however, the amount under the stratum corneum, which is related to the local skin safety of the chemical, cannot be predicted. This article describes the principles of permeation of chemicals across the skin, the relationship between skin permeability and concentration in the skin, and the method for calculating the chemical concentration under the stratum corneum using skin permeation parameters.

UI	MeSH Term	Description	Entries
D004058	Diffusion	The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.	Diffusions
D004817	Epidermis	The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).
D000279	Administration, Cutaneous	The application of suitable drug dosage forms to the skin for either local or systemic effects.	Cutaneous Drug Administration,Dermal Drug Administration,Drug Administration, Dermal,Percutaneous Administration,Skin Drug Administration,Transcutaneous Administration,Transdermal Administration,Administration, Dermal,Administration, Transcutaneous,Administration, Transdermal,Cutaneous Administration,Cutaneous Administration, Drug,Dermal Administration,Drug Administration, Cutaneous,Skin Administration, Drug,Administration, Cutaneous Drug,Administration, Dermal Drug,Administration, Percutaneous,Administrations, Cutaneous,Administrations, Cutaneous Drug,Administrations, Dermal,Administrations, Dermal Drug,Administrations, Percutaneous,Administrations, Transcutaneous,Administrations, Transdermal,Cutaneous Administrations,Cutaneous Administrations, Drug,Cutaneous Drug Administrations,Dermal Administrations,Dermal Drug Administrations,Drug Administrations, Cutaneous,Drug Administrations, Dermal,Drug Skin Administrations,Percutaneous Administrations,Skin Administrations, Drug,Skin Drug Administrations,Transcutaneous Administrations,Transdermal Administrations
D012867	Skin	The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.
D012869	Skin Absorption	Uptake of substances through the SKIN.	Absorption, Skin,Intracutaneous Absorption,Intradermal Absorption,Percutaneous Absorption,Transcutaneous Absorption,Transdermal Absorption,Absorption, Intracutaneous,Absorption, Intradermal,Absorption, Percutaneous,Absorption, Transcutaneous,Absorption, Transdermal,Absorptions, Intracutaneous,Absorptions, Intradermal,Absorptions, Percutaneous,Absorptions, Skin,Absorptions, Transcutaneous,Absorptions, Transdermal,Intracutaneous Absorptions,Intradermal Absorptions,Percutaneous Absorptions,Skin Absorptions,Transcutaneous Absorptions,Transdermal Absorptions