THE USE OF NANOTECHNOLOGY FOR TARGETED AND CONTROLLED DRUG DELIVERY
The purpose of a drug delivery system (DDS) is to deliver a drug efficiently, improve the effect of the drug and reduce its side effects. The main goal for developing such delivery systems is to minimize drug degradation and loss, to prevent harmful side effects and to increase bioavailability. Targeting is the ability to direct the drug loaded system to the site of interest. Targeted and controlled drug delivery technology and application have progressed over the last six decades. This progression started in the 1950s with the introduction of the first sustained release formulation. The first generation of drug delivery focused on developing oral and transdermal sustained release systems and establishing controlled drug release mechanisms. The second generation was dedicated to the development of zero-order release systems, self-regulated drug delivery systems, long-term depot formulations and nanotechnology-based delivery systems. The latter part of the second generation was largely focused on studying nanoparticle formulations. Nano- and micro-particles have turned out to be promising tools for the targeted delivery of drugs to specific anatomical sites. Some of the advantageous areas in which nanotechnology efforts are being made include vaccine adjuvants and delivery systems, nanostructured applications used in orthopaedics and wound management, controlled release drug delivery system, delivery vehicles that enhance circulation and targeting of drugs to specific cells and systems that improve the solubility of poorly water soluble drugs. This paper highlights the progress of targeted and/or controlled drug delivery with emphasis on nanoparticles and its applications as a drug delivery system.