Review on Nanosuspension as a Novel Method for Solubility and Bioavailability Enhancement of Poorly Soluble Drugs

Abstract

The formulation development of a drug is majorly based on the solubility of drugs. Nearly 40% of newly developed drugs show poor water solubility. Several approaches are used for the increasing solubility of such drugs for formulation development. Nanosuspension is one such attractive tactic which can be used for the enhancement of solubility, stability as well as bioavailability of such drugs. Nanosuspension can be defined as a two-phasic dosage form where solid drug particles of size less than 1 μm are dispersed in an aqueous phase with the help of a stabilizer. Particle size reduction in the nanoscale causes an increase in the surface area leading to an increase in dissolution rate and ultimately bioavailability is increased. A variety of excipients are used for the formulation of nanosuspension. Stabilizers, surfactants, co-surfactants, natural as well as organic solvents, buffers, salts, polyols, osmogents, and cryoprotectants are used in the formulation of nanosuspension. Various methods used in the formulation of nanosuspension can be classified into top-down and bottom-up approaches. Wet milling, high-pressure homogenization, anti-solvent techniques, melt emulsification, supercritical fluid extraction and ultrasonic homogenization are some of the methods for the preparation of nanosuspension. These methods are easy and appropriate for all poor water-soluble drugs. Nanosuspensions technology can be applied for the preparation of oral, pulmonary, injectable, ocular as well as targeted drug delivery. This review emphasizes various advantages and disadvantages of nanosuspension, its methods of preparation, formulation approaches, evaluation parameters, pharmaceutical applications, marketed products and patents of nanosuspension.