26A REVIEW ON SIGNIFICANCE OF NANOCRYSTALS IN DRUG DELIVERYFor the past few decades, there has been a considerable research interest in the area of drug delivery by using particulate delivery systems as carriers for small and large molecules. Significance of nanocrystal drugs is mentioned in this review. Nanocrystals are aggregates anywhere from a few hundred to tens of thousands of atoms that combine in to a crystalline form of matter known as a "cluster". They are used as a physical approach to alter and improve the pharmacokinetic and pharmacodynamic properties of various types of drug molecules. They have been used invivo to protect the drug entity in the systemic circulation. The method of preparations of nanocrystal is down, top down and bottom up, spray drying and so new techniques. These approaches are paving the way to the development of nanosized objects which are able to perform multiple technological tasks. There are several important advantages of nanocrystal formulations such as, enhanced oral bioavailability, improved dose proportionality, reduced food effects, suitability for administration by all routes and possibility of sterile filtration due to decreased particle size range. Selection depends upon the sites and to deliver the drug at a controlled and sustained rate to the site of action. Here, we review various aspects of nanocrystals formulation, characterization, effect of their characteristics and their pharmaceutical applications in delivery of drug molecules and therapeutic genesbrahmaiahmph@gmail.comReview322013Nanocrystals,Solubility,Particle sizes,Milling,BioavailabilityCH Balamarkonda,V Srinuvasa Rao,Patan Adamkhan,Sreekanth Nama,B Brahmaiah,K SasikanthDepartment of Pharmaceutics, Priyadarshini Institute of Pharmaceutical Education & Research (PIPER), 5th Mile, Pulladigunta, Kornepadu (V), Vatticherukuru (M), Guntur-522017, Andhra Pradesh, India,Department of Pharmaceutics, Priyadarshini Institute of Pharmaceutical Education & Research (PIPER), 5th Mile, Pulladigunta, Kornepadu (V), Vatticherukuru (M), Guntur-522017, Andhra Pradesh, India,Department of Pharmaceutics, Priyadarshini Institute of Pharmaceutical Education & Research (PIPER), 5th Mile, Pulladigunta, Kornepadu (V), Vatticherukuru (M), Guntur-522017, Andhra Pradesh, India,Department of Pharmaceutics, Priyadarshini Institute of Pharmaceutical Education & Research (PIPER), 5th Mile, Pulladigunta, Kornepadu (V), Vatticherukuru (M), Guntur-522017, Andhra Pradesh, India,Department of Pharmaceutics, Priyadarshini Institute of Pharmaceutical Education & Research (PIPER), 5th Mile, Pulladigunta, Kornepadu (V), Vatticherukuru (M), Guntur-522017, Andhra Pradesh, India,Department of Pharmaceutics, Priyadarsh