Predicting Skin Penetration from Different Vehicles - Assignment Example

Download file to see previous pages There are two routes that can be used to penetrate into normal human skin. The two routes are the appendageal route and the transepidermal route. The appendageal makes use of its sebaceous glands to penetrate into human skin along with the sweat glands and the hair follicles. These routes are also called the shunt routes because they circumvent penetrate making use of the stratum corneum. These routes come with very high permeability but they are not very significant because they cover a relatively smaller area of 0.1% of the total skin than the transepidermal route. It is however important for the larger polar molecules, for which the stratum corneum penetration is quite impossible (William, Barry, 1992).
The molecules make contact with the horny layer (stratum corneum) of the epidermis in the transepidermal route. The two micro routes namely the transcellular and intercellular are there to help in penetration. The pathway to be taken is mainly made certain by the partition coefficient (log K). So, by default, the hydrophilic drugs prefer the intracellular domains while the lipophilic permeants make use of the intercellular route. It is mainly the tortuous intercellular pathway which is a major barrier to permeation of some of the drugs (Fartasch, Bassukas, Dipegen, 1993)
This figure represents the potential pathways to penetrate into the skin. The number 1 path shows the intact horny layer, number 2 path shows the hair follicles with the associated sebaceous glands and the number 3 shows the pathway across the sweat glands.
The easy transport of molecules is usually restricted by the barrier properties of the epidermis. It is essential for a molecule to have certain characteristics including; low molecular weight, moderate lipophilicity, and solubility to be able to amply penetrate. However even if a molecule shows these characteristics, it sometimes becomes necessary to find extra measures. ...Download file to see next pagesRead More