Nanocarriers for transdermal drug delivery

Abstract

Transdermal drug delivery offers an attractive alternative to the conventional drug-delivery methods of oral administration and injection. Apart from the convenience and noninvasiveness, the skin also provides a " reservoir " that sustains delivery over a period of days. It offers multiple sites to avoid local irritation and toxicity, yet it can also offer the option of concentrating drugs at local areas to avoid undesirable systemic effects. However, at present, the clinical use of transdermal delivery is limited by the fact that very few drugs can be delivered transdermally at a viable rate. This difficulty is because the stratum corneum of skin acts as an efficient barrier that limits penetration of drugs through the skin, and few noninvasive methods are known to significantly enhance the penetration of this barrier. In order to increase the range of drugs available for transdermal delivery, the use of nanocarriers has emerged as an interesting and valuable alternative for delivering lipophilic and hydrophilic drugs throughout the stratum corneum with the possibility of having a local or systemic effect for the treatment of many different diseases. These nanocarriers (nanoparticles, ethosomes, dendrimers, liposomes, etc) can be made of a lot of different materials, and they are very different in structure and chemical nature. They are too small to be detected by the immune system, and furthermore they can deliver the drug in the target organ using lower drug doses in order to reduce side effects.