ABSTRACT
The main barrier to percutaneous absorption of xenobiotics is the stratum corneum (the Latin words for the outer horny layer of skin) that covers the epidermis layer, the precursor layer to the stratum corneum. The layers under the epidermis include the dermis, and the subcutaneous region that covers the muscle. The hair follicles, sweat glands, and two types of gland-apocrine and eccerineare the appendages of the skin. The passage of xenobiotic is mostly through the epidermis and the widely distributed hair follicle and eccrine glands on the surface of the body.
