Solid Lipid Nanoparticles: an Advanced Drug Delivery System

Solid lipid nanoparticles are at the forefront of the rapidly developing field of nanotechnology with several potential applications in drug delivery, research and clinical medicine, as well as in other varied sciences. Solid lipid nanoparticle (SLN) dispersions have been proposed as a new type of colloidal drug carrier system suitable for intravenous administration. Solid lipid nanoparticles (SLNs) technology represents a promising new approach to lipophilic drug delivery. Solid lipid nanoparticles are spherical lipid particles ranging in size from 1 to 1000 nm and are dispersed in water or in aqueous surfactant solution. It is identical to an oil-in-water emulsion, but the liquid lipid (oil) of the emulsion has been replaced by a solid lipid, i.e., yielding Solid Lipid Nanoparticles. SLN are particles made from solid lipid or lipid blends produced by high pressure homogenization. The biodegradable and bioacceptable nature of SLNs makes them less toxic as compared to polymeric nanoparticles. SLNs can also be used to improve the bioavailability of drugs. In this present review this new approach is discussed in terms of their advantages, disadvantages, methods, characterization, pharmacokinetic studies, in-vivo studies, in-vitro studies, and special features INTRODUCTION: A high potential for drug delivery has been attributed to particulate drug carriers, especially small particles such as micro particles and colloidal system in nanometer range . Nano particulate drug delivery system may offer plenty of advantages over conventional dosage forms which include improved, reduced toxicity, enhanced bio distribution and improved patient compliance . Colloidal particles ranging in size between 10 and 1000 nm are known as nanoparticles. They are manufactured from synthetic/natural polymers and ideally suited to optimize drug delivery and reduce toxicity. Over the years, they have emerged as a variable substitute to liposomes as drug carriers. The successful implementation of nanoparticles for drug delivery depends on their ability to penetrate through several anatomical barriers, sustained release of their contents and their stability in the nanometer size. However, the scarcity of safe polymers with regulatory approval and their high cost have limited the wide spread application of nanoparticles to clinical medicine . To overcome these limitations of polymeric nanoparticles, lipids have been put forward as an alternative carrier, particularly for lipophilic pharmaceuticals. These lipid nanoparticles are known as solid lipid nanoparticles (SLNs), which are attracting wide attention of formulators world-wide . SLNs are colloidal carriers developed in the last decade as an alternative system to the existing traditional carriers (emulsions, liposomes and poly Solid lipid nanoparticle (SLN) dispersions have been proposed as a new type of Correspondence to Author: A. Raghu Nandan Reddy Department of pharmaceutics, Krupanidhi College of pharmacy, Sarjapura main road, Carmelaram post, Bangalore-560035,