title: Characterization of the generation of radiolabeled monodisperse albuterol particles using the spinning-top aerosol generator.
abstract: Inhaled radiolabeled aerosols provide invaluable information about in vivo drug deposition. Here, we report our methodology for radiolabeling and imaging monodisperse pharmacologic aerosols in order to study basic aerosol science concepts of drug delivery within the human airways.
  
  
  METHODS
  We used a spinning-top aerosol generator to produce (99m)Tc-labeled monodisperse albuterol sulfate aerosols of 1.5-, 3-, and 6- micro m mass median aerodynamic diameter.
  
  
  RESULTS
  In vitro Andersen cascade validation data showed that technetium and albuterol were coassociated on each impactor stage for all 3 aerosols, and the radiolabeling process itself did not affect their particle size distributions. Good-quality gamma-camera scintigraphic images of lung and extrathoracic deposition were obtained within an asthmatic patient.
  
  
  CONCLUSIONS
  We have successfully radiolabeled and imaged monodisperse albuterol aerosols within the human lungs. This novel technique provides an important tool to relate fundamental concepts of aerosol particle behavior, in vivo deposition, and therapeutic clinical response.
authors.affiliation: Department of Thoracic Medicine, National Heart and Lung Institute, Imperial College London, London, United Kingdom. o.usmani@imperial.ac.uk
authors.forename: Omar S
authors.initials: OS
authors.lastname: Usmani
authors.forename: Martyn F
authors.initials: MF
authors.lastname: Biddiscombe
authors.forename: S Richard
authors.initials: SR
authors.lastname: Underwood
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Barnes
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000336:Aerosols / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics*; D000420:Albuterol / Q000008:administration & dosage / Q000737:chemistry* / Q000493:pharmacokinetics*; D001249:Asthma / Q000000981:diagnostic imaging / Q000378:metabolism*; D016503:Drug Delivery Systems / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D007553:Isotope Labeling / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging / Q000378:metabolism; D008657:Metabolic Clearance Rate; D009330:Nebulizers and Vaporizers; D010316:Particle Size; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000138:chemical synthesis / Q000493:pharmacokinetics; D013667:Technetium / Q000008:administration & dosage / Q000737:chemistry* / Q000493:pharmacokinetics*
chemical_list: D000336:Aerosols; D019275:Radiopharmaceuticals; D013667:Technetium; D000420:Albuterol