ABSTRACT

During the 1980s and 1990s, several drug delivery systems were developed to improve the efficiency of drugs and minimize toxic side effects [6]. The early nano-and microparticles were mainly formulated

from poly(alkylcyanoacrylate) [6]. Initial promise of microparticles was dampened by the fact that there was a size limit for the particles to cross the intestinal lumen into the lymphatic system following oral delivery. Likewise, the therapeutic effect of drug-loaded nanoparticles was relatively poor due to rapid clearance of the particles by phagocytosis postintravenous administration. In recent years, headway has been made in solving this problem by the addition of surface modifications to nanoparticles. Nanoparticles, such as liposomes, micelles, worm-like micelles, polymersomes, and vesicles have also been proposed recently in the literature as promising drug delivery vehicles because of their small size and hydrophilic outer shell.