Recent advances in nanotechnology demonstrate the increased attention that is now being turned to the supramolecular assembly of simple components for therapeutic and diagnostic purposes. This review contains detail about materials used in synthesis of nanosponges, different methods of preparation, characterization and applications. Targeted drug delivery to specific sites is the significant problem which is being faced by the medical researchers. The new developed colloidal system called nanosponge has potential to overcome these problems. Nanosponges are novel class of hypercross linked polymer based colloidal structures consisting of solid nanoparticles with colloidal sizes and nanosized cavities. They enhance stability, reduce side effects and modify drug release. The outer surface is typically porous, allowing sustain release of drug to specific sites, prevent drug and protein degradation. Nanosponges are small sponges with a size of about a virus, which can be filled with a wide variety of drugs. These tiny sponges can circulate around the body until they encounter the specific target site and stick on the surface and begin to release the drug in a controlled and predictable manner. Because the drug can be released at the specific target site instead of circulating throughout the body it will be more effective for a particular given dosage. To varying the portion of cross-linkers and polymers, the nanosponge particles can be made larger or smaller size. These particles are capable of carrying both lipophilic and hydrophilic substances and of improving the solubility of poorly water soluble molecules. It has various applications like enhancing bioavailability of drugs and delivery of drugs into oral, topical as well as parenteral routes.

Target-specific drug-delivery systems for the administration of pharmaceutical compounds enable the localization of drugs to target sites within the body.  The basic component of drug delivery systems is an appropriate carrier that protects the drug from rapid degradation or clearance and thereby enhances drug concentration in target tissues. Niosome are microscopic non-ionic surfactant bilayer vesicles obtained on hydration of synthetic nonionic surfactants, with or without incorporation of cholesterol or their lipids. The amphiphilic nature of niosomes promotes their efficiency in encapsulating lipophilic or hydrophilic drugs.  Noisome are promising vehicle for drug delivery and being non-ionic, more stable, inexpensive, biodegradable, biocompatible, non immunogenic and exhibit flexibility in their structural characterization. Various additives in niosomes include nonionic surfactant as film forming agent, cholesterol as stabilizing and rigidizing agent for the bilayer and various charge inducers which develop a charge on the surface of niosomes and stabilize the prepared formulation by the resulting repulsive forces. Niosomes have been widely evaluated for controlled release and targeted delivery for the treatment of cancer, viral infections, microbial diseases, psoriasis, leishmaniasis, migraine, parkinson and other diseases. Niosomes can prolong the circulation of the entrapped drug in body. Encapsulation of drug in vesicular system can be predicted to prolong the existence of drug in the systemic circulation and enhance penetration into target tissue, perhaps reduce toxicity if selective uptake can be achieved. In addition to conventional, oral and parenteral routes, they are amenable to be delivered by ocular, transdermal, vaginal and inhalation routes. Delivery of biotechnological products including vaccine delivery with niosomes is also an interesting and promising research area. More concerted research efforts, however, are still required to realize the full potential of these novel systems. This review article focuses on the concept of niosomes, advantages and disadvantages, composition, method of preparation, separation of unentrapped drug, factors influencing the niosomal formulation and characterization, marketed formulations of niosomes and also gives up to date information regarding recent applications of niosomes in drug delivery. Keyword:  Drug-delivery system, Niosomes,

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