Solid Lipid Nanoparticles : an Effective Lipid Based Technology for Poorly Water Soluble Drugs

Solid lipid nanoparticles (SLNs) are the effective lipid based colloidal carriers which were introduced as an alternative to the conventional carriers such as microemulsions, liposomes, microparticles and nanoparticles based on synthetic polymers or natural macromolecules. Typically they enhance the oral bioavailability of the low aqueous soluble drugs due to their potential to enhance gastrointestinal solubilization and absorption via selective lymphatic uptake. These properties can be harvested to improve the therapeutic efficacy of the drugs with low bioavailability, as well as to reduce their effective dose requirement. This paper presents an overview about the choice of the drug candidates, advantages, methods of preparation such as high pressure homogenization, ultrasonication/high speed homogenization, solvent evaporation/emulsification, supercritical fluid method, microemulsion based method and spray drying method are discussed. Appropriate analytical techniques for characterization of solid lipid nanoparticles such as photon correlation spectroscopy, scanning electron microscopy, differential scanning calorimetry etc. are discussed. Applications with respect of routes of administration such as oral, parenteral, topical, pulmonary etc are elaborated in detail. References of the most relevant literature published by various research groups around the world are provided.