Yasunori Morimoto

Section 6 – Transdermal patches

Publisher Summary nDrugs placed on the skin can be classified into two types: those that focus on the skin (epidermal) itself and the others that use the skin as a conveying agent. These vary in function, while transdermal therapeutic systems (TTS) used to treat the epidermal system specifically, transdermal drug delivery systems (TDDS) absorbed through the skin and distributed throughout the body. The patch type can maintain a constant, measured amount of drug delivered and its application is simple. Thus, it is suitable as a drug delivery system for the entire body. Patches are made into various structures and forms. They are largely divided into reservoir, matrix, and pressure sensitive (PSA) and tape types. Acceleration factors along with selection of drugs that have high transdermal absorption must be involved in any evaluation of the validity of transdermal delivery patches. Useful methods for absorption acceleration include chemical modifications (prodrug); use of chemical absorption accelerators; and physical methods like iontophoresis, phonophoresis, and electroporation.