Abstract

LIQUID CRYSTALS-CURRENT TRENDS AND FUTURE PERSPECTIVES

Radhika Parasuram Rajam*, Indhumathi Rajendran, Ramya Karuppannan and Anitha Balan

ABSTRACT

Liquid crystals are the materials that are in many ways intermediate between the liquid and solid states. Liquid crystals exhibit different molecular arrangements than the liquid and solid states. Liquid crystal systems are attracting significant attention due to their unique microstructures and physicochemical properties. The liquid crystalline state may result either from the heating of solids (thermotropic liquid crystals) or from the action of certain solvents or solids (lyotropic liquid crystals). The two main types of liquid crystals are: smectic (soap like or grease like) or nematic (threadlike). Liquid crystals are becoming the choicest system for R and D professionals in the formulation development sector. LC based systems can provide specific advantages of thermodynamic stability, high solubilisation levels, improved bioavailability, protection against oxidation and controlled release properties to the pharmaceuticals. Liquid crystal materials are unique in their properties and uses. Thus material characterization and understanding of the liquid crystalline states of active pharmaceuticals can yield wide range of options to enhance formulation performance for drug delivery. This review will provide basic information about liquid crystals, their types, phases involved, and uses in pharmaceutical and non-pharmaceutical industry.

Keywords: Liquid crystals (LCs), mesophases, phases involved, pharmaceutical uses, Lyotropic liquid crystals, thermotropic liquid crystals, recent approach.