title: Nanocrystal Based Drug Delivery System: Conventional and Current Scenario.
abstract: BACKGROUND
  Most of the chemical substances which emerge out as potential drug candidates (Active Pharmaceutical Ingredients) are either weak acids or weak bases. The poor aqueous solubility of these drug substances is a common concern. Several R&D centers are focused on developing suitable, economic, simpler and more feasible solubility enhancement techniques for increasing the solubility and thereby bioavailability of such drug substances. Nanocrystals are one of the preferred approaches for solubility enhancement in the last few decades.
  
  
  METHODS
  Nanocrystal as a solubility enhancement approach is widely explored and discussed by many researchers. Despite being the most simple and feasible technique, nanocrystal formulation has its own limitations. The present review enlightens some novel technologies which can overcome disadvantages of conventionally well-established bottom-up and top-down techniques used for nanocrystal formulation. Results/Applications: The present review summarizes and also highlights the correlation between some novel findings like reduction in the melting point of drug and nanocrystal formulation. The review also includes a special section emphasizing on the patents granted in the field of nanocrystals. The review includes more than ten patents focusing on several aspects of nanocrystal formulations as manufacturing methods, formulation components and conventional and novel applications of nanocrystals in new and hybrid forms. Aspects related to advantages of nanocrystals over other formulation approaches, targeting (Active and Passive) through nanocrystal formulations and issues related to nanotoxicity are also reviewed and discussed in the present article.
  
  
  CONCLUSIONS
  The findings, research outcomes and patents related to nanocrystal formulations, reported in the present review confirm the potential of the stated system as a drug delivery tool. The review emphasizes on the urge for further exploration required in the area of nanocrystal system for enhancing its efficiency as a drug delivery and a diagnostic tool.
authors.affiliation: Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, India.
authors.forename: Shreya
authors.initials: S
authors.lastname: Thakkar
authors.affiliation: Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, India.
authors.forename: Viral
authors.initials: V
authors.lastname: Shah
authors.affiliation: Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, India.
authors.forename: Manju
authors.initials: M
authors.lastname: Misra
authors.affiliation: Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, India.
authors.forename: Kiran
authors.initials: K
authors.lastname: Kalia
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000037:antagonists & inhibitors / Q000378:metabolism; D001682:Biological Availability; D004333:Drug Administration Routes; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry*; D010330:Patents as Topic; D004364:Pharmaceutical Preparations / Q000737:chemistry* / Q000378:metabolism; D012995:Solubility
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D004337:Drug Carriers; D004364:Pharmaceutical Preparations
keywords: Bioavailability enhancement; drug targeting; nanocrystals; nanotoxicity; quantum dots; solubility enhancement.