Penetration Enhancer Classification (2005)

Introduction ........................................................................................................................................ 4 Drug Transport Routes through Human Skin ................................................................................... 4 Enhancing Transdermal Drug Delivery ............................................................................................. 5Interactions between Drug and Vehicle ........................................................................................ 5 Selection of Correct Drug or Prodrug........................................................................................ 5 Chemical Potential Adjustment .................................................................................................. 6 Ion Pairs and Complex Coacervates .......................................................................................... 7 Eutectic Systems.......................................................................................................................... 7Vesicles and Particles...................................................................................................................... 7 Liposomes and Analogs.............................................................................................................. 7 High-Velocity Particles................................................................................................................ 8Stratum Corneum Modified............................................................................................................ 8 Hydration .................................................................................................................................... 8 Chemical Enhancers ................................................................................................................... 9Stratum Corneum Bypassed or Removed.................................................................................... 11 Microneedle Array .................................................................................................................... 11 Stratum Corneum Ablated ........................................................................................................ 11 Follicular Delivery..................................................................................................................... 13Electrically Assisted Techniques................................................................................................... 13 Ultrasound (Phonophoresis, Sonophoresis)............................................................................ 13 Iontophoresis ............................................................................................................................ 13 Electroporation ......................................................................................................................... 13 Magnetophoresis....................................................................................................................... 14 Radio Waves.............................................................................................................................. 14 Photomechanical Wave ............................................................................................................ 14References......................................................................................................................................... 14This chapter presents a brief overview of the topics dealt with in more detail in subsequent contributions to this book, that is, the major ways by which scientists attempt to overcome the highly impermeable nature of human skin so as to deliver drugs at clinically active body concentrations. The organization of the material essentially follows the review published in 2001.1 To conserve space, most of the 200 references from that work will not be repeated here, nor those listed in subsequent chapters in this book.