title: Pulmonary clearance rate of two chemically different forms of inhaled pertechnetate.
abstract: Attempts to image the pulmonary deposition site of radiolabeled aerosols delivered by dry powder inhalers (DPIs) and pressurized metered-dose inhalers (pMDIs) using single photon emission computed tomography (SPECT) have been limited by the rapid pulmonary clearance of radiolabel. To determine whether aqueous solubility of the radiolabel is a significant factor, the pulmonary clearance rates of two chemically different forms of 99mTc were calculated. A dry powder formulation of terbutaline sulphate was radiolabeled for inhalation by Turbuhaler (AstraZeneca) using the water-soluble salt sodium pertechnetate and the water-insoluble salt tetraphenylarsonium pertechnetate. A pilot study was conducted during which two control subjects each inhaled the two radiolabeled aerosols on separate days. Intrasubject clearance rates for the two species were very similar. It was therefore concluded that water insolubility of the pertechnetate salt alone was not enough to extend the lung residency time of the radiolabel.
authors.affiliation: Department of Nuclear Medicine, Southampton General Hospital, England. P.S.Walker@soton.ac.uk
authors.forename: P S
authors.initials: PS
authors.lastname: Walker
authors.forename: J H
authors.initials: JH
authors.lastname: Conway
authors.forename: J S
authors.initials: JS
authors.lastname: Fleming
authors.forename: E
authors.initials: E
authors.lastname: Bondesson
authors.forename: L
authors.initials: L
authors.lastname: Borgström
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000336:Aerosols / Q000008:administration & dosage / Q000493:pharmacokinetics; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D002626:Chemistry, Pharmaceutical; D016903:Drug Monitoring; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000187:drug effects*; D008297:Male; D009079:Mucociliary Clearance / Q000187:drug effects*; D009330:Nebulizers and Vaporizers; D010865:Pilot Projects; D011208:Powders; D011312:Pressure; D019275:Radiopharmaceuticals / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics*; D013670:Sodium Pertechnetate Tc 99m / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics*; D012995:Solubility; D013726:Terbutaline / Q000008:administration & dosage / Q000493:pharmacokinetics; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D000336:Aerosols; D001993:Bronchodilator Agents; D011208:Powders; D019275:Radiopharmaceuticals; D013670:Sodium Pertechnetate Tc 99m; D013726:Terbutaline