title: Disposition of nebulized pentamidine measured using the direct radiolabel 123I-iodopentamidine.
abstract: The pulmonary deposition of nebulized pentamidine (300 mg, Respirgard II nebulizer) was measured in seven human immunodeficiency virus (HIV)-positive men using a new radiopharmaceutical, 123I-iodopentamidine. Mean total pulmonary deposition was 15.3 mg or 5.1% of the initial nebulizer dose. Further studies in two of the patients showed that at 24 h, 87% of deposited 123I was retained in the lungs. Small amounts of activity (expressed as a percentage of the initial nebulizer activity) were also detected over the thyroid (0.4%), bladder (1%) and gut (0.7%). The ratio of 123I activity to pentamidine concentration was similar in the nebulizer solution and urine. These results suggest that 123I-pentamidine may be sufficiently stable in vivo to be used to study the biodistribution of inhaled and parenteral pentamidine in humans.
authors.affiliation: Department of Nuclear Medicine, St. Thomas' Hospital, London, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: O'Doherty
authors.forename: S H
authors.initials: SH
authors.lastname: Thomas
authors.forename: C J
authors.initials: CJ
authors.lastname: Page
authors.forename: P J
authors.initials: PJ
authors.lastname: Blower
authors.forename: N T
authors.initials: NT
authors.lastname: Bateman
authors.forename: T O
authors.initials: TO
authors.lastname: Nunan
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D006679:HIV Seropositivity / Q000188:drug therapy*; D006801:Humans; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D008297:Male; D009330:Nebulizers and Vaporizers; D010419:Pentamidine / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D007457:Iodine Radioisotopes; D010419:Pentamidine