Study to Characterize the Durability of Hypertonic Saline to Enhance Mucociliary Clearance in Healthy Subjects

Inclusion Criteria: * Healthy subjects, without respiratory or cardiac comorbidities * Age 18-55 years, inclusive * FEV1 \> 80% predicted and FEV1/FVC ratio \>70% * Non-pregnant female subjects must be either not sexually active, post-menopausal, surgically sterilized, or agree to use an appropriate "double-barrier" method (such as a diaphragm and condom); or, must currently be using a prescribed transdermal, injection, implant, or oral contraceptive during study participation * Subjects who are capable of providing their written informed consent to participate in the study Exclusion Criteria: * History of smoking \> 10 pack-years * Any history of smoking within 60 days of screening * Acute upper or lower respiratory illness within 30 days of screening * Respiratory medication for any indication within 30 days of screening * History of asthma, chronic bronchitis, or other chronic lung disease * History of intolerance to hypertonic saline * Women who are pregnant, lactating, or of childbearing potential who are unwilling to use an acceptable method of contraception throughout the duration of the study. * Any condition that, in the opinion of the investigator, would potentially jeopardize the safety of the participant or the integrity of the study * History of radiation exposure within the past year that would cause the subject to exceed limits for adults established by Federal Regulations * Subjects who, in the opinion of the Principal Investigator, should not participate in the study