INTRODUCTION
Target oriented drug delivery systems are the areas of the major
interest in the modern pharmaceutical research. The selective drug
delivery to the target tissues increases the therapeutic efficacy of the
drug and reduces its undesirable effect to non target tissues. The
concept of drug targeting or site specific drug delivery was
introduced first time by Paul Elrich in 1909, when he reported
‘magic bullet’ to deliver a drug to the desired site of action without
affecting the non target organs or tissues (Juliano, 1980) by
associating the drug with a pharmacologically “inactive carrier”
capable of conveying the drug selectively towards its target cells.
Drug targeting is defined as the ability to direct a therapeutic agent
specifically to the desired site of action with little or no interaction
with non target tissues (Bremier, 1987)
The main goal of a site specific drug delivery system is not only to
increase the selectivity and drug therapeutic index, but also to
reduce the toxicity of the drug. (Widder et al., 1982)
Vanlerbeghe et al. (1972) first reported the niosomes as a feature of
cosmetic industry. In 1979, Handjanivila et al. reported that the
hydration of a mixture of cholesterol and single alkyl chain, resulted
in formation of non ionic surfactant vesicular systems (i.e.
Niosomes).
These non ionic surfactant vesicles can entrap both hydrophilic and
lipophilic drugs, either in aqueous layer or in the vesicular
membrane made of lipid materials, which can be used to prolong the
circulation of the entrapped drugs. Due to the presence of non ionic
surfactant and the lipid, there is a better targeting of drug(s) to
tumor, liver and brain. Thus, they are useful in targeting of the drug
for treating cancers, parasitic, viral and other microbial diseases
more effectively.