title: Enhancement of nasal absorption of insulin using chitosan nanoparticles.
abstract: OBJECTIVE
  To investigate the potential of chitosan nanoparticles as a system for improving the systemic absorption of insulin following nasal instillation.
  
  
  METHODS
  Insulin-loaded chitosan nanoparticles were prepared by ionotropic gelation of chitosan with tripolyphosphate anions. They were characterized for their size and zeta potential by photon correlation spectroscopy and laser Doppler anemometry, respectively. Insulin loading and release was determined by the microBCA protein assay. The ability of chitosan nanoparticles to enhance the nasal absorption of insulin was investigated in a conscious rabbit model by monitoring the plasma glucose levels.
  
  
  RESULTS
  Chitosan nanoparticles had a size in the range of 300-400 nm, a positive surface charge and their insulin loading can be modulated reaching values up to 55% [insulin/nanoparticles (w/w): 55/100]. Insulin association was found to be highly mediated by an ionic interaction mechanism and its release in vitro occurred rapidly in sink conditions. Chitosan nanoparticles enhanced the nasal absorption of insulin to a greater extent than an aqueous solution of chitosan. The amount and molecular weight of chitosan did not have a significant effect on insulin response.
  
  
  CONCLUSIONS
  Chitosan nanoparticles are efficient vehicles for the transport of insulin through the nasal mucosa.
authors.affiliation: Department Pharmaceutical Technology, School of Pharmacy, Santiago de Compostela, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Fernández-Urrusuno
authors.forename: P
authors.initials: P
authors.lastname: Calvo
authors.forename: C
authors.initials: C
authors.lastname: Remuñán-López
authors.forename: J L
authors.initials: JL
authors.lastname: Vila-Jato
authors.forename: M J
authors.initials: MJ
authors.lastname: Alonso
mesh_terms: D000042:Absorption; D000281:Administration, Intranasal; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002686:Chitin / Q000031:analogs & derivatives* / Q000494:pharmacology; D048271:Chitosan; D005079:Excipients; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000494:pharmacology; D007328:Insulin / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000494:pharmacology; D008297:Male; D008863:Microspheres; D009297:Nasal Mucosa / Q000187:drug effects / Q000378:metabolism*; D011817:Rabbits; D013268:Stimulation, Chemical
chemical_list: D001786:Blood Glucose; D005079:Excipients; D007004:Hypoglycemic Agents; D007328:Insulin; D002686:Chitin; D048271:Chitosan