The above diagram shows how a typical penetration/evaporation system is set-up. A sample of the membrane or excised skin is placed over the penetration cell, dermal side down, and is held in place with an o-ring. After the topical preparation is applied to the surface of the skin or membrane, an evaporation cell is clamped over it.

To measure penetration through the skin or membrane, a receptor solution is pumped from an i. v. bag through a manifold and into the receptor compartment of the penetration cell where it bathes the underside of the skin or membrane (the dermal side of the skin). The receptor solution then exits to a fraction collector where the appearance of the compound(s) of interest in the fractionated outflow gives a measure of percutaneous absorption over time.

Diffusion cells are used to measure the penetration of cosmetics, toxin or drugs into and through the skin or membrane. Evaporation cells are used to measure the evaporation of these substances from the skin, a measurement that also affects penetration and can answer the question of how much of a topical preparation simply stays on or in the skin. Penetration and evaporation values obtained with diffusion cells can approximate the values obtained using in vivo methods such as tape-stripping, urinalysis/radioassay, and punch biopsy.

We have worked closely with local universities and research facilities to develop our line of diffusion cells for in vitro skin studies. In addition to the Skin Permeation System, we can also manufacture a custom cell design.

Below is a summary chart of our cell designs.