A comprehensive review on formulation characterization and preparation techniques of drug loaded nanosuspension

Nanosuspensions are submicron colloidal dispersions consisting of nanosized drug particles stabilized by surfactants or polymers to enhance the dissolution and bioavailability of poorly water-soluble drugs. Nanotechnology can be used to overcome critical formulation issues such as erratic absorption, low solubility, and permeability related problems. Reduction in particle size increases surface area, which in turn enhances dissolution and absorption rate. The particle size, zeta potential, and crystalline state significantly influence the stability and dissolution rate and in vivo performance of nanosuspensions. These characteristics are generally evaluated for properties with methods such as DSC, X-ray diffraction and PCS. There are usually two types of preparation methods, namely, top-down (high-pressure homogenization and media milling) and bottom-up approaches, which include precipitation, evaporation of solvent and supercritical fluid technique. These preparation methods represent a simple, efficient and scalable approach for improving the bioavailability of poorly aqueous soluble drugs. This strategy is versatile and holds tremendous promise in the modern drug delivery system since nanosuspensions can be prepared for different routes of administration such as oral, parenteral, ophthalmic and pulmonary.