title: Realgar nanoparticle-based microcapsules: preparation and in-vitro/in-vivo characterizations.
abstract: OBJECTIVE
  The aim of this study was to prepare microcapsules for the oral delivery of realgar nanoparticles (RN) that are also capable of improving its stability.
  
  
  METHODS
  RN and RN-based microcapsules (RNM) were prepared using ball milling and solvent evaporation techniques, respectively. Properties such as particle size, ζ-potential (ZP), morphology and X-ray diffractometer (XRD) were investigated. In addition, drug release, bioavailability and antitumour studies were also performed.
  
  
  RESULTS
  The nanoparticles appeared round or elliptical in shape with a mean size of 85.4 ± 3.5 nm and a ZP of -34.3 ± 1.7 mV. The obtained RNM appeared spherical and not aggregated with a relatively narrow size distribution. XRD analysis revealed that ball milling technique did not change the crystallinity of the realgar powder. RN and RNM exhibited considerable higher release of As2 S2 , bioavailability and antitumour efficacies compared with crude realgar. Furthermore, RNM could protect RN directly exposed to the air and light, and therefore increased the stability of the RN.
  
  
  CONCLUSIONS
  The developed RNM demonstrated a greater potential as a delivery system for realgar.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China; School of Pharmacy, Jiangsu University, Zhenjiang, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Shi
authors.forename: Nianping
authors.initials: N
authors.lastname: Feng
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Omari-Siaw
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology*; D001152:Arsenicals / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology*; D004337:Drug Carriers; D065546:Drug Liberation; D004355:Drug Stability; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D051381:Rats; D017208:Rats, Wistar; D013440:Sulfides / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology*; D013499:Surface Properties; D013678:Technology, Pharmaceutical; D014961:X-Ray Diffraction
chemical_list: D000970:Antineoplastic Agents; D001152:Arsenicals; D004337:Drug Carriers; D013440:Sulfides; C058317:arsenic disulfide
keywords: antitumour efficacy; bioavailability; in-vitro release; microcapsules; realgar nanoparticles