ABSTRACT
Transdermal delivery of drugs and vaccines is an effective alternative to oral and parenteral routes of administration. Epidermis is the outermost layer of skin and composed of four strata: the stratum germinativum, the stratum granulosum, the stratum lucidum, and stratum corneum. Skin is considered as a remarkably efficient barrier designed to keep our insides in and the outside out. The modulation of this barrier property, including permeability to drugs, chemicals, and bioactive agents is the prime requirement as well as target for transdermal delivery. Micro/nanoparticles are suitable vehicles for delivery of the drug, proteins, and peptides. Liposomes are colloidal particles containing concentric bimolecular layers and possess ability to encapsulate both polar and non-polar drugs. Niosomes are non-ionic surfactant based vesicles similar to liposomes formed by hydration of synthetic non-ionic surfactants and cholesterol. Ethosomes are soft, malleable ethanolic phospholipid vesicles tailored for enhanced delivery of active agents.
