Jyuhn-Huarng Juang

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A pH-sensitive nanoparticle (NP) system composed of chitosan and poly(gamma-glutamic acid) was prepared for the oral delivery of insulin. The biodistribution study in a rat model showed that some of the orally administered NPs were retained in the stomach for a long duration, which might lead to the disintegration of NPs and degradation of insulin. To(More)
In this study, we report the biodistribution of aspart-insulin, a rapid-acting insulin analogue, following oral or subcutaneous (SC) administration to rats using the single-photon emission computed tomography (SPECT)/computed tomography (CT). Oral delivery of aspart-insulin was achieved using a pH-responsive nanoparticle (NP) system composed of chitosan(More)
Exendin-4 is a potent insulinotropic agent in diabetes patients; however, its therapeutic utility is limited due to the frequent injections required. In this study, an orally available exendin-4 formulation, using an enteric-coated capsule containing pH-responsive NPs, was developed. Following oral administration of (123)I-labeled-exendin-4 loaded NPs in(More)
A variety of approaches have been studied in the past to overcome the problems encountered with the oral delivery of insulin, but with little success. In this study, self-assembled nanoparticles (NPs) with a pH-sensitive characteristic were prepared by mixing the anionic poly-gamma-glutamic acid solution with the cationic chitosan solution in the presence(More)
pH-Responsive nanoparticles composed of chitosan (CS) and poly-gamma-glutamic acid (gamma-PGA) blended with tripolyphosphate (TPP) and MgSO(4) (multi-ion-crosslinked NPs) were prepared and characterized to determine their effectiveness in the oral delivery of insulin. Their counterparts without TPP and MgSO(4) (NPs) were used as a control. FT-IR and XRD(More)
Chitosan (CS) and its derivatives have been investigated as paracellular permeation enhancers for facilitating the oral bioavailability of hydrophilic macromolecules. As is well known, CS can transiently open the tight junctions (TJs) between epithelial cells, thus enhancing the paracellular permeability. However, the signaling mechanism that is related to(More)
In the study, chitosan (CS) was conjugated with trimethyl groups for the synthesis of N-trimethyl chitosan (TMC) polymers with different degrees of quaternization. Nanoparticles (NPs) self-assembled by the synthesized TMC and poly(gamma-glutamic acid) (gamma-PGA, TMC/gamma-PGA NPs) were prepared for oral delivery of insulin. The loading efficiency and(More)
Syngeneic transplantation of 200 mouse islets under the kidney capsule usually fails to cure streptozocin-induced diabetes. We hypothesized that this number of islets, if engrafted in a normoglycemic environment, could expand their mass and improve their function to restore normoglycemia. Therefore, 200 freshly isolated mouse islets were transplanted under(More)
Basal hepatic glucose production (HGP) was determined in obese and nonobese normal subjects and patients with noninsulin-dependent diabetes mellitus (NIDDM) using [3-3H]glucose and the nonsteady state equations of Steele. When HGP was estimated at hourly intervals from 0800-1300 h, it became evident that calculated values for HGP fell for the first 2-4 h(More)
Decoy receptor 3 (DCR3) halts both Fas ligand- and LIGHT-induced cell deaths, which are required for pancreatic beta cell damage in autoimmune diabetes. To directly investigate the therapeutic potential of DCR3 in preventing this disease, we generated transgenic nonobese diabetic mice, which overexpressed DCR3 in beta cells. Transgenic DCR3 protected mice(More)