title: [Enhancement of gastrointestinal absorption of chitosan-coated insulin-loaded poly (lactic-co-glycolic acid) nanoparticles].
abstract: OBJECTIVE
  To study chitosan-coated poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) on enhancing gastrointestinal absorption of insulin.
  
  
  METHODS
  Insulin-loaded PLGA multiple emulsions were prepared by a double-emulsion method. Using chitosan as a stabilizer, chitosan-coated PLGA-NPs was prepared. The changes of the morphology, size distribution and Zeta potential of the NPs were examined. The encapsulation efficiency was determined by HPLC. The release behaviors in vitro were assessed, and the hypoglycemic effects were evaluated by monitoring the glucose levels in diabetic rats.
  
  
  RESULTS
  Chitosan-coated PLGA-NPs showed a narrow size of distribution and regular surface with layer structure and their Zeta potential can be changed by chitosan. Chitosan-coating increased the encapsulation efficiency of insulin, reduced the initial burst and improved the release behavior of the NPs. About 14-16 h after intragastric administration of chitosan-coated INS-PLGA-NPs, the plasma glucose level decreased significantly compared with intragastric administration of same dose of non-coated NPs (P < or = 0.05), and the relative pharmacological availability was increased up to (15.4 +/- 1.2)%.
  
  
  CONCLUSIONS
  Chitosan-coated PLGA-NPs could enhance gastrointestinal absorption of insulin.
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002686:Chitin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D048271:Chitosan; D003921:Diabetes Mellitus, Experimental / Q000097:blood; D004337:Drug Carriers; D016503:Drug Delivery Systems; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology; D007328:Insulin / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology; D007408:Intestinal Absorption / Q000187:drug effects*; D019344:Lactic Acid / Q000737:chemistry; D008297:Male; D036103:Nanotechnology; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001786:Blood Glucose; D004337:Drug Carriers; D007004:Hypoglycemic Agents; D007328:Insulin; D011108:Polymers; D002686:Chitin; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D048271:Chitosan