Nanosuspensions: A Literature Review

Abstract: Nanosuspensions (NSs) are nanosized particles that have recently become one of the most important areas in nanopharmaceuticals. NSs have a high market value owing to their providing an increased dissolution rate and improved bioavailability. This is because reducing the particle size and increasing the surface area leads to a faster dissolution process. In addition, Nanosuspensions alter drug pharmacokinetics and thus improve its safety and effectiveness. These benefits can enhance poorly soluble drugs’ bioavailability in many routes of administration, including oral, pulmonary, ocular, dermal, parenteral or nasal for local or systemic effects. Nanosuspensions are mainly aqueous drug nanoparticle formulations. In addition, NSs consist of organic solvents, stabilizers, surfactants, lyoprotectants, co-surfactants, and other ingredients. The selection of stabilizer types, including surfactants and/or polymers, and their concentrations, is a crucial factor for NS formulations. NSs preparation can be performed using top-down methods, which include high-pressure homogenization, wet milling, dry milling, and co-grinding or bottom-up methods which include liquid emulsion, anti-solvent precipitation, and sono-precipitation. Nowadays, methods based on the combination of these two techniques are performed. NSs can be prepared as liquid formulation or dosage forms, or exposed to post-preparation methods including spray drying, freeze drying, or spray freezing. These methods are applied to convert the liquid state to the solid state to prepare several dosage forms including tablets, capsules, powders, pellets, films, or gels. This review discusses the properties of NSs, their preparation methods and characterizations, and highlights the recent progress, practical considerations and applications of NSs in various administration routes.