How are drugs absorbed in transdermal administration?

Transdermal administration involves the absorption of drugs through the skin, typically using a patch that is applied directly to the skin's surface. This method allows for controlled release of medication into the bloodstream over a prolonged period. The skin acts as a barrier, but it is permeable to certain drugs, enabling them to pass through the epidermis and dermis layers, eventually reaching the systemic circulation.

This mode of delivery is preferred for certain medications because it can provide a steady release of drug into the body, reducing the need for frequent dosing and minimizing fluctuations in drug levels. In contrast, other methods mentioned, such as swallowing, involve the gastrointestinal tract; nasal membranes pertain to drug delivery through the nasal passages, and injections bypass the skin entirely by delivering drugs directly into the bloodstream or muscle tissue. Therefore, transdermal administration stands out for its unique pathway of absorption through the skin, making it a targeted and effective delivery system for certain therapeutic agents.