title: Preparation and characterization of nanoparticles shelled with chitosan for oral insulin delivery.
abstract: Nanoparticles (NPs) composed of chitosan (CS) and poly(gamma-glutamic acid) (gamma-PGA) were prepared by a simple ionic-gelation method for oral insulin delivery. Fourier transform infrared (FT-IR) spectra indicated that CS and gamma-PGA were ionized at pH 2.5-6.6, while X-ray diffractograms demonstrated that the crystal structure of CS was disrupted after it was combined with gamma-PGA. The diameters of the prepared NPs were in the range of 110-150 nm with a negative or positive surface charge, depending on the relative concentrations of CS to gamma-PGA used. The NPs with a positive surface charge (or shelled with CS) could transiently open the tight junctions between Caco-2 cells and thus increased the paracellular permeability. After loading of insulin, the NPs remained spherical and the insulin release profiles were significantly affected by their stability in distinct pH environments. The in vivo results clearly indicated that the insulin-loaded NPs could effectively reduce the blood glucose level in a diabetic rat model.
authors.affiliation: Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
authors.forename: Yu-Hsin
authors.initials: YH
authors.lastname: Lin
authors.forename: Fwu-Long
authors.initials: FL
authors.lastname: Mi
authors.forename: Chiung-Tong
authors.initials: CT
authors.lastname: Chen
authors.forename: Wei-Chun
authors.initials: WC
authors.lastname: Chang
authors.forename: Shu-Fen
authors.initials: SF
authors.lastname: Peng
authors.forename: Hsiang-Fa
authors.initials: HF
authors.lastname: Liang
authors.forename: Hsing-Wen
authors.initials: HW
authors.lastname: Sung
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D018938:Caco-2 Cells; D002463:Cell Membrane Permeability; D048271:Chitosan / Q000737:chemistry* / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy; D016503:Drug Delivery Systems; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000008:administration & dosage*; D053758:Nanoparticles / Q000737:chemistry*; D011099:Polyglutamic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D051381:Rats; D014961:X-Ray Diffraction
chemical_list: D001786:Blood Glucose; D007328:Insulin; C511775:poly(gamma-glutamic acid); D011099:Polyglutamic Acid; D048271:Chitosan