Chemical penetration enhancers: a patent review.
BACKGROUND
Ever since transdermal drug delivery came into existence, it has offered great promises, although most of them are yet to be fulfilled owing to some intrinsic restrictions of the transdermal route. On the positive side, transdermal drug delivery systems present advantages including non-invasiveness, prolonged therapeutic effect, reduced side effects, improved bioavailability, better patient compliance and easy termination of drug therapy. The greatest hindrance in the percutaneous delivery is the obstruction property of the stratum corneum, the outermost layer of the skin, in addition to usual problems such as skin binding, skin metabolism, cutaneous toxicity and prolonged lag times.


OBJECTIVE
This paper reviews investigations on the feasibility and application of penetration enhancers as described in recent patents, which help in the selection of a suitable sorption promoter(s) for enhanced delivery of medicaments through the skin.


METHODS
The patents granted under various categories of penetration enhancers have been discussed including fatty acids, terpenes, fatty alcohol, pyrrolidone, sulfoxides, laurocapram, surface active agents, amides, amines, lecithin, polyols, quaternary ammonium compounds, silicones, alkanoates and so on.


CONCLUSIONS
Scores of promising chemicals have been harnessed for their skin permeation promoting capacity as mentioned earlier. In future, many more chemicals and putative enhancers are likely be documented and patented.
Ahad
Abdul
A
Faculty of Pharmacy, Department of Pharmaceutics, Hamdard University, New Delhi, India.
Aqil
Mohammed
M
Kohli
Kanchan
K
Chaudhary
Hema
H
Sultana
Yasmin
Y
Mujeeb
Mohammed
M
Talegaonkar
Sushama
S
D000279:Administration, Cutaneous; D000818:Animals; D002626:Chemistry, Pharmaceutical; D016503:Drug Delivery Systems; D005079:Excipients / Q000737:chemistry*; D006801:Humans; D010330:Patents as Topic; D010539:Permeability; D004364:Pharmaceutical Preparations / Q000008:administration & dosage* / Q000378:metabolism; D012867:Skin / Q000378:metabolism; D012869:Skin Absorption
D005079:Excipients; D004364:Pharmaceutical Preparations