title: Surface-modified PLGA nanosphere with chitosan improved pulmonary delivery of calcitonin by mucoadhesion and opening of the intercellular tight junctions.
abstract: Surface-modified DL-lactide/glycolide copolymer (PLGA) nanospheres with chitosan (CS) were prepared by the emulsion solvent diffusion method for pulmonary delivery of peptide, i.e., elcatonin. The nanosphere suspension was successfully aerosolized with a nebulizer similar to the drug solution, whereas the microsphere suspensions could not be aerosolized. After pulmonary administration, CS-modified PLGA nanospheres were more slowly eliminated from the lungs than unmodified PLGA nanospheres. CS-modified PLGA nanospheres loaded with elcatonin reduced blood calcium levels to 80% of the initial calcium concentration and prolonged the pharmacological action to 24 h, which was a significantly longer duration of action than that by CS-unmodified nanospheres. These results were attributed to the retention of nanospheres adhered to the bronchial mucus and lung tissue and sustained drug release at the adherence site. In addition, CS and CS on the surface of the nanospheres enhanced the absorption of drug. The rank order of the absorption of the model drugs with CS solution was carboxyfluorescein>FITC-dextran-4 (FD-4; Mw. 4000)>FD-21 (Mw. 21,000)>FD70 (Mw. 70,000), which corresponded to the molecular weights ([Mw.] given in parentheses). The absorption-enhancing effect may have been caused by opening the intercellular tight junctions.
authors.affiliation: Gifu Pharmaceutical University, 5-6-1, Mitahora-higashi Gifu 502-8585, Japan.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kuno
authors.forename: Shohei
authors.initials: S
authors.lastname: Sugimoto
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kawashima
mesh_terms: D000042:Absorption; D000268:Adhesiveness; D000280:Administration, Inhalation; D000336:Aerosols; D000818:Animals; D002116:Calcitonin / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D048271:Chitosan / Q000737:chemistry*; D016503:Drug Delivery Systems; D004655:Emulsions; D006168:Guinea Pigs; D019344:Lactic Acid / Q000737:chemistry*; D008168:Lung / Q000378:metabolism*; D008297:Male; D008863:Microspheres; D008970:Molecular Weight; D009092:Mucous Membrane; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties; D019108:Tight Junctions / Q000737:chemistry*
chemical_list: D000336:Aerosols; D004655:Emulsions; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D002116:Calcitonin; D048271:Chitosan; C012755:elcatonin