title: Lymphatic uptake of pulmonary delivered radiolabelled solid lipid nanoparticles.
abstract: Lymphatic drainage plays an important role in the uptake of particulates in the respiratory system, being also associated to the spreading of lung cancer through metastasis development. In recent years solid lipid nanoparticles (SLN) have been proposed as carriers of anti-tumoural drugs, for their low toxicity and surface characteristics make them suitable for either imaging (gamma-scintigraphy) or therapy upon encapsulation of cytotoxic drugs. Assessment of inhaled radiolabelled SLN biodistribution is described in the present work.
  
  
  METHODS
  Nanoparticles (200 nm) were radiolabelled with 99mTc using the lipophilic chelator D,L-hexamehylpropyleneamine oxime (HMPAO). Biodistribution studies were carried out following aerosolisation and administration of a 99mTc-HMPAO-SLN suspension to a group of adult male Wistar rats. A 60 min dynamic image acquisition was performed in a gamma-camera, followed by static image collection at 30 min intervals up to 4 h postinhalation. Radiation counting was performed in organ samples, collected after the animals were sacrificed.
  
  
  RESULTS
  The data show an important and significant uptake of the radiolabelled SLN into the lymphatics after inhalation, and a high rate of distribution in periaortic, axillar and inguinal lymph nodes.
  
  
  CONCLUSIONS
  Results indicate that SLN could be effective colloidal carriers for lymphoscintigraphy or therapy upon pulmonary delivery.
authors.affiliation: Unidade de Cièncias e Tecnologia Farmacêuticas, Faculdade de Farmácia da Universidade de Lisboa, Av. Gama Pinto, 1649-003 Lisboa, Portugal. mvideira@ff.ul.pt
authors.forename: Mafalda A
authors.initials: MA
authors.lastname: Videira
authors.forename: M F
authors.initials: MF
authors.lastname: Botelho
authors.forename: Ana C
authors.initials: AC
authors.lastname: Santos
authors.forename: Luis F
authors.initials: LF
authors.lastname: Gouveia
authors.forename: J J Pedroso
authors.initials: JJ
authors.lastname: de Lima
authors.forename: António J
authors.initials: AJ
authors.lastname: Almeida
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D003102:Colloids; D004337:Drug Carriers; D007091:Image Processing, Computer-Assisted; D007553:Isotope Labeling; D008055:Lipids; D008168:Lung / Q000000981:diagnostic imaging / Q000378:metabolism*; D008208:Lymphatic System / Q000378:metabolism*; D061305:Lymphoscintigraphy; D008297:Male; D008863:Microspheres; D019275:Radiopharmaceuticals / Q000008:administration & dosage* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013147:Spirometry; D019690:Technetium Tc 99m Exametazime / Q000493:pharmacokinetics; D014018:Tissue Distribution
chemical_list: D003102:Colloids; D004337:Drug Carriers; D008055:Lipids; D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime