Sci & Tech

Therapeutic Areas


Skin, Wound, Mucosa



As a rough guide, skin is impermeable to molecules with a molecular weight above about 800 u. Hydration and other "permeation enhancers" may increase this limiting weight.

Formulations like creams, ointments, gels, emulsion foams, microemulsions and oils (occasionally "self-emulsifying") are used to distribute a product on the target area.

When possible, local application of active substances is generally favored over systemic (e.g. oral) delivery. It decreases risk of unwanted side effects and also of registration issues.



Wound formulations often use gels, emulsions and oils as vehicle.

They protect the wound during healing from environmental stress and may enhance healing and scar formation by controlling humidity and nutrition supply.

Results from a wound healing study showing two references
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Nail care and diseases

Nail permeated by with red dye as compared with untreated nail

Nail diseases

Permeation of an active drug through a nail is severely restricted by nail structure.

Therefore, as a rule, a permeation enhancer is used in addition to hydration of the nail.

Microscope photograph of a cut surface from of a partially dehydrated nail clip. The nail outer surface is shown towards right.
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Gastric absorption

In order to be absorbed in the gastric area, a substance must be dissolved.

Alternatively it should initially be protected, e.g. be shielded in the stomach, and then unshielded in a region, like duodenum, where absorption is desired.

Solubility of a pharmaceutical substance in a three component mixture. Darker color represents higher solubility
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