TD-0903 Pharmacokinetics Study in Healthy Participants With Supplemental Oxygenation

Inclusion Criteria: * Body mass index (BMI) ≥ 18.0 and ≤ 35.0 kg/m2 and weighs at least 50 kg at screening * Medically healthy with no clinically significant medical history, physical examination, spirometry, laboratory profiles, vital signs or ECGs * Forced expiratory volume of 1 second (FEV1) ≥80% predicted at screening and prior to dosing * No clinically significant abnormalities in the results of laboratory * Female subjects must be either of non-childbearing potential or if of childbearing potential, subject must not be pregnant or breastfeeding, and must agree to use a highly effective birth control method * Male subjects must agree to use condoms to prevent potential fetal or partner exposure through seminal fluid, in addition to the use of highly effective pregnancy prevention measures with female partners of childbearing potential * Able to understand the correct technique for the use of the nebulizer device * Other inclusion criteria apply Exclusion Criteria: * History or presence of clinically significant medical or psychiatric condition * Abnormal ECG measurements at screening * Any signs of respiratory tract infection within 6 weeks of screening * Has a current bacterial, parasitic, fungal, or viral infection; any infection requiring hospitalization or intravenous antibiotics within 6 months prior to screening * Has any condition of the oro-laryngeal or respiratory tract * History or presence of alcoholism or drug abuse * Positive urine drugs of abuse test * Positive urine or breath alcohol results * Uses or has used tobacco or nicotine-containing products (e.g., cigarettes, cigars, chewing tobacco, snuff, patches etc.) within 6 months prior to screening * Tests positive for active COVID-19 * Additional exclusion criteria apply