title: [Radiolabeling and biodistribution studies of polymeric nanoparticles as adjuvants for ocular vaccination against brucellosis].
abstract: OBJECTIVE
  To optimize radiolabeling with (99m)Tc of mannosylated Gantrez(®) nanoparticles loaded with the Brucella Ovis antigen (Man-NP-HS) and to carry out biodistribution studies in mice after ocular administration of the nanoparticles.
  
  
  METHODS
  Man-NP-HS nanoparticles were prepared by the solvent displacement method. They were purified, lyophilized and characterized. Following this, they were radiolabeled with 74 MBq of (99m)TcO4(-) previously reduced with an acidic stannous chloride solution, working in absence of oxygen and at a final pH of 4. Radiolabeling yield was evaluated by TLC. Biodistribution studies were carried out in mice after ocular administration of the formulation and control of free (99m)TcO4(-). To do so, the animals were humanely killed at 2 and 24hours after the ocular administration and activity in organs was measured in a Gamma counter.
  
  
  RESULTS
  Radiolabeling yield obtained was greater than 90%. Biodistribution studies of (99m)Tc-Man-NP-HS showed radioactivity accumulated at 2 and 24hours in nasal and ocular mucosa and gastrointestinal tract, in contrast to biodistribution of free (99m)TcO4(-) that remained concentrated in the skin around the eye and gastrointestinal tract.
  
  
  CONCLUSIONS
  Biodistribution studies of (99m)Tc-Man-NP-HS after ocular instillation have made it possible to demonstrate its biodistribution in nasal mucosa and gastrointestinal tract. This characteristic is essential as an antigenic delivery system throughout the ocular mucosa. This, together with its elevated immune response, effective protection and intrinsic avirulence make them a suitable anti-Brucella vaccine candidate.
authors: Unidad de Radiofarmacia, Departamento de Medicina Nuclear, Clínica Universidad de Navarra, Pamplona, España.
authors: M
authors: M
authors: Sánchez-Martínez
authors: R
authors: R
authors: da Costa Martins
authors: G
authors: G
authors: Quincoces
authors: C
authors: C
authors: Gamazo
authors: C
authors: C
authors: Caicedo
authors: J M
authors: JM
authors: Irache
authors: I
authors: I
authors: Peñuelas
mesh_terms: D060433:Administration, Ophthalmic; D000818:Animals; D002004:Brucella Vaccine / Q000008:administration & dosage*; D016503:Drug Delivery Systems; D005260:Female; D007553:Isotope Labeling / Q000379:methods; D008298:Maleates; D051379:Mice; D008807:Mice, Inbred BALB C; D053758:Nanoparticles / Q000008:administration & dosage* / Q000378:metabolism*; D011108:Polymers; D011145:Polyvinyls; D019275:Radiopharmaceuticals; D013667:Technetium; D014018:Tissue Distribution; D014611:Vaccination / Q000379:methods*
chemical_list: D002004:Brucella Vaccine; D008298:Maleates; D011108:Polymers; D011145:Polyvinyls; D019275:Radiopharmaceuticals; C058026:polyvinylmethoxyethylene-maleic anhydride copolymer; D013667:Technetium