Nanoprecipitation as emerging technique for nanosuspension in ocular drug delivery

The ocular conventional formulation shows poor ocular bioavailability due to the precorneal elimination of drugs that includes rapid tear turnover, poor permealibility of drugs into the corneal membrane, naso lacrimal drainage and less residence time in the conjuctival sac. This poor ocular bioavailability need to be improved by frequent instillation of dose to achieve the therapeutic effect. Nanotechnology is one of the better approaches to overcome challenges of conventional ocular drug delivery. The nanotechnology related ocular products available in the market are limited and nanotechnology is still in its earlier stage in drug delivery. Hence polymeric ocular nanosuspension is one of the strategies currently used to improve drug absorption across biological membranes. Nanoprecipitation technique (NPTN) is easy, less energy consuming, and widely applicable without any additives for the manufacture of desirable size nanoparticles. The Nanosuspension formed by diffusion of drug and polymer containing solvent into the anti solvent, the polymer droplets immediately precipitate or adsorbed with drugs. The rapid nanoparticle formation is described by marangoni effect, which is subjected to interfacial turbulences that occur at the interface of the solvent and the anti solvent. Nanosuspension can be further sterilized and subsequently evaluate for various parameters like particle size, drug release, zeta potential character. This review article mainly focused on conventional nanoprecipitation, modified nanoprecipitation technology and effect variables in nanosuspension preparation.