Nanotechnology Based Targeted Drug Delivery: Current Status and Future Prospects for Drug Development

Abstract

Nanotechnology mediated delivery of therapeutic agents is one of the rapidly emerging fields today that has gained significant commercial and academic attention. It is a promising approach to alleviate the drawbacks of conventional therapy and major limitations associated with drug development like poor water solubility, low bioavailability, drug toxicity etc. Nano-scale drug-delivery systems can be devised to tune and regulate release pharmacokinetics, pharmacodynamics, solubility, immunocompatibility, cellular uptake, biodistribution and to minimize toxic side effects, thus enhancing therapeutic index of traditional pharmaceuticals (Emerich & Thanos, 2007). They can be used to deliver both small-molecule drugs and various classes of biomacromolecules such as peptides, proteins, plasmid DNA and synthetic oligodeoxynucleotides. Nanoparticle mediated drug delivery, thus has the potential to contribute significantly in the drug development process which has relied on conventional formulation strategies that are often inadequate. An underlying concept in drug development process is to establish a link between in vitro potency, physicochemical properties and absorption, distribution, metabolism, excretion and toxicity characteristics of a drug candidate which is often cited as a major contributing factor in the failure of drug development. While the nanoparticle mediated sustained release of drugs offers an obvious therapeutic advantage, the targeted delivery of drugs in the body is required to prevent the release of therapeutics at non-specific sites and unwanted sideeffects. The conjugation of targeting moieties with drug-loaded nanoparticles can be used for receptor-mediated and targeted delivery. Such targeted nanoparticles have the characteristics of a perfect drug delivery system that tends to maximize the therapeutic activity while minimizing the toxic side effects of drugs.