Nanosuspension Technology for Poorly Water Soluble Drugs: An Overview

Poorly water-soluble drugs often exhibit variable bioavailability and bio-inequivalence due to its poor water-solubility leading to hurdles in formulation development efforts. There are number of formulation approaches like micronisation, solubilization using cosolvents, precipitation techniques etc., to resolve the problems of low solubility and low bioavailability. Each of them have their own limitations. Other techniques like microemulsions, solid dispersions and inclusion complexes using cyclodextrins, even though showed increased solubility, are not applicable for drugs which are insoluble in both aqueous and organic media. The next development step is transformation of the micronized drug to drug nanoparticles and nanosuspensions. Nanoparticulate drug delivery system may offer plenty of advantages over conventional dosage forms which include improved efficacy, reduced toxicity, enhanced biodistribution and improved patient compliance. Nanosuspension technology offers novel solution for such poorly soluble drugs. Nanosuspension consists of pure poorly water soluble drugs with or without any matrix material suspended in dispersion and can be surfactant free or comprise of surfactants or stabilizers or both. Nanosuspensions differ from nanoparticles, which are polymeric colloidal carriers of drugs (Nanospheres and nanocapsules), and from solid-lipid nanoparticles (SLN), which are lipidic carriers of drug. This review focuses on characterization, properties, method of preparations, formulation considerations and various applications in drug delivery systems of nanosuspensions.