Transdermal Delivery

Description

The introduction of substances into the body via unbroken Skin.  The most common example of Transdermal Delivery is the use of Skin Creams and other personal care products.  Patches are another vehicle for introducing substances into the body using Transdermal Delivery.

 The major pathway through which topically-applied substances enter the body is via the Stratum Corneum layer of the Skin.  ^[1]

 To a lesser extent topically-applied substances also enter the body through Hair Follicles and Sweat Glands.

 For some substances Transdermal Delivery provides 100% absorption/bioavailability.

 Transdermal Delivery produces no “first-pass” effect.

 Transdermal Delivery causes a longer duration of action for the substance administered by this method.

 Transdermal Delivery is associated with very slow absorption.  Substances must be in contact with the Skin for relatively long periods before they are fully absorbed.

Substances used to transport active substances into the Skin are known as Carrier Vehicles and substances that increase the absorption of other substances into the Skin are known as Penetration Enhancers.