Abstract

Supercooled smectic nanoparticles are under investigation as potential drug carrier systems. Lipid nanoemulsions have the disadvantage of insufficient stabilization whereas solid lipid nanoparticles suffer from disadvantages like low drug incorporation tendencies. Hence there was a need to develop new drug delivery systems which could overcome these disadvantages. Liquid crystalline state also called as mesophase, has macroscopic viscosity and a less orderly state than solids but greater than that of liquids. The liquid crystalline state is classified as nematic and smectic phase. In the smectic phase the molecules are aligned side by side forming a layer and this property of the smectic phase is made use in pharmaceuticals. The various components used include lipid matrices such as cholesteryl esters and stabilizer systems. High- pressure melt homogenization and solvent evaporation are the two widely used methods for their preparation. Drugs, which can be incorporated, are mostly poorly water soluble drugs and drugs which possess very low recrystallization tendencies. In this review an attempt has been made to highlight composition, stabilizer systems, and matrix systems, method of preparation, characterization, applications and safety aspects of the supercooled smectic nanoparticles as drug carrier systems.

Keywords: Cholesteryl esters, mesophase, smectic phase, supercooled nanoparticles, thermotropic liquid crystals, thermotropic mesomorphs