title: Biodistribution and lymph node retention of polysaccharide-based immunostimulating nanocapsules.
abstract: The adjuvant properties of polyglucosamine/squalene-based nanocapsules (PG-nanocapsules) associated with different subunit antigens has been previously reported. Thus, the aim of the present study was to monitor the biodistribution of PG-nanocapsules and their affinity for the draining lymph nodes after subcutaneous (s.c.) injection. The nanocapsules were efficiently radiolabeled with indium-111 ((111)In) (labeling efficiency of 98%). The diameter and zeta potential values of the unlabeled nanocapsules was preserved after the radiolabeling process and only 20% of the (111)In dissociated from the nanocapsules after 48h of incubation in serum. The radiolabeled nanocapsules and the control (111)InCl3 in saline solution (18.5MBq (500μCi) in 100μL) were injected s.c. in New Zealand White rabbits. The γ-scintigraphy imaging analysis revealed a slow clearance of the nanocapsules from the injection site and their progressive accumulation in the popliteal lymph node over time (3.8%±1.2 of the injected dose at 48h). Indeed, the clearance rate of the nanocapsules from the injection site was significantly slower than that of the control (free (111)InCl3), which rapidly drained into systemic circulation and accumulated mainly in excretion organs (i.e. kidneys and liver). In contrast, the biodistribution of nanocapsules was preferably limited to the lymphatic circulation. These results suggest that the immune potentiating effect previously observed for PG-nanocapsules is mainly due to the formation of a depot at the injection site, which was followed by a slow drainage into the lymphatic system and a prolonged retention in the lymph nodes.
authors: Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, 15705 Campus Vida, Santiago de Compostela, Spain; Pharmacy and Pharmaceutical Technology Department, School of Pharmacy, University of Santiago de Compostela, 15705 Campus Vida, Santiago de Compostela, Spain.
authors: Sara
authors: S
authors: Vicente
authors: Radiology Department, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229-3900, USA.
authors: Beth A
authors: BA
authors: Goins
authors: Pharmacy and Pharmaceutical Technology Department, School of Pharmacy, University of Santiago de Compostela, 15705 Campus Vida, Santiago de Compostela, Spain; Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela 15706, Spain.
authors: Alejandro
authors: A
authors: Sanchez
authors: Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, 15705 Campus Vida, Santiago de Compostela, Spain; Pharmacy and Pharmaceutical Technology Department, School of Pharmacy, University of Santiago de Compostela, 15705 Campus Vida, Santiago de Compostela, Spain; Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela 15706, Spain.
authors: María J
authors: MJ
authors: Alonso
authors: Radiology Department, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229-3900, USA. Electronic address: Phillips@uthscsa.edu.
authors: William T
authors: WT
authors: Phillips
mesh_terms: D000276:Adjuvants, Immunologic / Q000493:pharmacokinetics; D000818:Animals; D005944:Glucosamine / Q000493:pharmacokinetics; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D061305:Lymphoscintigraphy; D008297:Male; D053769:Nanocapsules; D011134:Polysaccharides / Q000493:pharmacokinetics*; D011817:Rabbits; D014018:Tissue Distribution
chemical_list: D000276:Adjuvants, Immunologic; D053769:Nanocapsules; D011134:Polysaccharides; D005944:Glucosamine
keywords: Biodistribution; Chitosan; Imaging; Lymph node; Nanocarrier; Nanovaccine