Transdermal drug delivery systems (TDDS), also known as transdermal therapeutic systems (TTS), refer to one route of administration administered dermally for topical or systemic therapeutic purposes. Is the third largest drug delivery system after oral administration, injection, and is a method commonly used to rate drug absorption through the skin.

For a drug, entry into the systemic circulation is required to exert an effect, whereas cosmetic products need not enter the systemic circulation through the skin, and the exertion of its efficacy as a topical dermal formulation requires that an adequate amount of the active ingredient reaches and remains in the skin and superficial tissues so that the maximum efficacy of the active ingredient in the product can be exerted. Research on the process of absorption and distribution of active ingredients in cosmetic products at the target site of the skin is very important, and it will be very helpful for the development of cosmetic active ingredients.

Therefore, different species, different anatomical sites, and different ages all lead to differences in the thickness of the stratum corneum, which can affect the transdermal absorption. In addition to this, the molecular weight, level of ionization, concentration, dosage form, and length of dermal exposure of the drug or cosmetic product all directly affect the extent of absorption.

● Testing items：

Collagen protein / Chitosan /  Sodium hyaluronate