transepidermaler

Transepidermal refers to a process or substance that passes through the epidermis, the outermost layer of the skin. It is a term commonly used in pharmacology and dermatology to describe the penetration of substances into or through the skin.

The epidermis acts as a barrier, and its structure plays a crucial role in regulating what enters or leaves the body. Transepidermal absorption is the movement of molecules from the external environment through the various layers of the epidermis and into the dermis, the layer beneath. This absorption can be influenced by factors such as the size and lipophilicity of the molecule, the condition of the skin barrier, and the presence of enhancers.

In pharmaceutical contexts, transepidermal drug delivery is a significant area of research. It involves designing formulations that can effectively transport active pharmaceutical ingredients across the epidermal barrier to achieve a local or systemic therapeutic effect. Transdermal patches, for example, are designed to facilitate transepidermal drug absorption over a sustained period.

Transepidermal water loss (TEWL) is another important concept. It refers to the passive diffusion of water from the inside of the body across the epidermis to the atmosphere. TEWL is a measure of the integrity of the skin barrier function. An elevated TEWL can indicate damage to the epidermis, leading to increased dryness and susceptibility to external irritants.