title: Crosslinked chitosan-dextran sulfate nanoparticle for improved topical ocular drug delivery.
abstract: OBJECTIVE
  To examine the benefits of chitosan-dextran sulfate nanoparticles (CDNs) as a topical ocular delivery system with lutein as a model drug.
  
  
  METHODS
  CDNs were developed by polyelectrolyte complexation of positively charged chitosan (CS) and negatively charged dextran sulfate (DS). 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and polyethylene glycol 400 (PEG400) were used as co-crosslinking and stabilizing agents, respectively. The influence of these on the properties of CDNs, including drug release and mucoadhesiveness, was examined. The chemical stability of lutein in CDNs (LCDNs) was also examined.
  
  
  RESULTS
  Typically, LCDNs showed a spherical shape, possessing a mean size of ~400 nm with a narrow size distribution. The entrapment efficiency of lutein was in the range of 60%-76%. LCDNs possessing a positive surface charge (+46 mV) were found to be mucoadhesive. The release profile of LCDNs followed Higuchi's square root model, suggesting drug release by diffusion from the polymer matrix. Lutein in LCDNs showed increased chemical stability during storage compared to its solution form.
  
  
  CONCLUSIONS
  These characteristics of CDNs make them suitable for drug delivery to the ocular surface.
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand ; The Center of Excellence for Innovation in Chemistry (PERCH-CIC), Commission on High-Education, Ministry of Education, Thailand.
authors.forename: Wanachat
authors.initials: W
authors.lastname: Chaiyasan
authors.affiliation: School of Optometry, Indiana University, Bloomington, Indiana, United States.
authors.forename: Sangly P
authors.initials: SP
authors.lastname: Srinivas
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand ; The Center of Excellence for Innovation in Chemistry (PERCH-CIC), Commission on High-Education, Ministry of Education, Thailand ; The Center of Excellence in Medical Biotechnology, Naresuan University, Phitsanulok, Thailand.
authors.forename: Waree
authors.initials: W
authors.lastname: Tiyaboonchai
mesh_terms: D002234:Carbodiimides / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D016264:Dextran Sulfate / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D065546:Drug Liberation; D004355:Drug Stability; D005079:Excipients / Q000737:chemistry; D007700:Kinetics; D014975:Lutein / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009883:Ophthalmic Solutions / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D055672:Static Electricity
chemical_list: C518491:1-ethyl-3-(3-(diethylamino)propyl)carbodiimide; D002234:Carbodiimides; D003432:Cross-Linking Reagents; D004337:Drug Carriers; D005079:Excipients; D009883:Ophthalmic Solutions; D011092:Polyethylene Glycols; D048271:Chitosan; D016264:Dextran Sulfate; C000595213:polyethylene glycol 400; D014975:Lutein