title: [Effects of the liposomes coated by chitosan and its derivatives on the gastrointestinal transit of insulin].
abstract: OBJECTIVE
  To study the effect of the liposomes coated by chitosan and its derivatives as oral dosage form for peptide drugs on the gastrointestinal (GI) transit of drugs.
  
  
  METHODS
  Insulin-liposomes were prepared by reversed-phase evaporation. The in situ perfusion experiment was used to investigate the enteral absorption of insulin. The hypoglycemic effects of insulin were investigated using the glucose oxidase method after administration in rats. The insulin concentrations of serum and enteral tissues were determined by radio-immunoassay in rats.
  
  
  RESULTS
  In in situ local intestinal perfusion experiment, the duodenum was the best segment for the absorption of the insulin liposomes coated by chitosan (CH) or chitosan-EDTA conjugates (CEC) , and double-coated by CH-CEC; the colon was the best segment for the absorption of the insulin solution from rat intestine; but the best segment for the absorption of the uncoated and N-trimethyl chitosan chloride (TMC) coated insulin liposomes was unclear. In all segments, the enteral absorption of the insulin liposomes double-coated by CH-CEC was superior to that of other insulin liposomes.
  
  
  CONCLUSIONS
  The insulin-liposomes coated by chitosan and its derivatives can enhance enteral absorption of insulin and increase stability of insulin in GI tract.
authors.affiliation: Department of Pharmaceutics, China Pharmaceutical University, Nanjing 210009, China.
authors.forename: Zheng-Hong
authors.initials: ZH
authors.lastname: Wu
authors.forename: Qi-Neng
authors.initials: QN
authors.lastname: Ping
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Lei
authors.forename: Jian-Ying
authors.initials: JY
authors.lastname: Li
authors.forename: Peng
authors.initials: P
authors.lastname: Cai
mesh_terms: D000818:Animals; D019540:Area Under Curve; D048271:Chitosan / Q000737:chemistry*; D003106:Colon / Q000378:metabolism; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D016503:Drug Delivery Systems; D004386:Duodenum / Q000378:metabolism; D004492:Edetic Acid / Q000737:chemistry; D005772:Gastrointestinal Transit; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D007328:Insulin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D007408:Intestinal Absorption; D008081:Liposomes; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D007004:Hypoglycemic Agents; D007328:Insulin; D008081:Liposomes; D048271:Chitosan; D004492:Edetic Acid