Abstract
Use of technologies on the skin-penetration enhancement is very important to apply many therapeutic drugs to transdermal drug delivery systems (TDDS). In addition, controlled release ability is also needed in the TDDS fabrication to have predetermined bioavailability and absorption rate of drugs. In this review, I introduce about 4 decades-history on TDDS and overall research on the chemical penetration-enhancers and physical means like iontophoresis and microneedles to increase skin permeation of drugs. Use of such penetration-enhancement methods leads to develop new TDDS having real controlled release ability of drugs. I also introduce new concept on the TDDS with internet of things (IoT). Such new TDDS IoT may be responsible for the center of the pharmaceutical formulations in the near future.
