This study evaluates the effect of pre-treatment with either cromolyn sodium or albuterol sulfate on the safety and tolerability or PUL-042 Inhalation Solution in healthy subjects.

Healthy subjects (8 per cohort) will be randomized to either pre-treatment or no pre-treatment (4 per group). The initial cohort will receive pre-treatment with cromolyn sodium. Subjects will be followed for 2 weeks for safety and tolerability, undergo a 2 week washout period and then be assigned to the alternative treatment (i.e., subjects who received cromolyn sodium prior to PUL-042 inhalation solution will not receive pretreatment) and then followed for an additional 2 weeks.

Subsequent cohort will receive pre-treatment with albuterol sulfate in a like manner.

Inclusion Criteria:

• Males or females of non-childbearing potential (defined as surgically sterilized [tubal ligation/hysterectomy/bilateral salpingo oophorectomy or post- menopausal for > 2 years) with a negative urine human chorionic gonadotropin (hCG) pregnancy test at the Screening Visit
• Body Mass Index (BMI) between 18 and 30 kg/m2
• Ability to perform spirometry according to American Thoracic Society standards
• Normal spirometry (forced expiratory volume in 1 second [FEV1] and forced vital capacity [FVC] ≥ 80% and ≤ 120% based on predicted values) at the Screening Visit and at Visit 2.
• Pulse oximetry ≥95% on room air
• Ability to understand and give informed consent
• Males willing to practice contraception (condom + spermicide) during the study and for 30 days after completion of the

Exclusion Criteria:

• Febrile (temperature ≥ 99.5°Fahrenheit)
• A history of use of any tobacco products during the year prior to the Screening Visit and a total exposure of > 5 pack years or a positive urine cotinine level at the Screening Visit
• Clinically significant laboratory finding as determined by the Principal Investigator or designee at the Screening Visit or at Visit 2
• Positive test for drugs of abuse (alcohol, cannabinoids, opiates, cocaine, amphetamine, barbiturates, benzodiazepine, phencyclidine)
• Any active medical problems requiring treatment
• Subjects who exhibit symptoms of respiratory infection or have experienced respiratory symptoms of an upper respiratory infection within 30 days prior to the Screening Visit.
• History of chronic pulmonary disease (eg, asthma [including atopic asthma, exercise induced asthma, or asthma triggered by respiratory infection], pulmonary fibrosis), pulmonary hypertension, or heart failure
• Any out of range QTc Fridericia (QTcF) or other clinically significant ECG findings as determined by the Principal Investigator or designee at Visit 2 or Visit 12.
• History of atopic reactions
• Administration of any anti-inflammatory therapy (eg, no steroidal anti-inflammatory drugs or corticosteroids) within 4 weeks prior to randomization or expected to be ongoing during the study
• An anticipated need for use of any inhaled medication during the study
• Intake of coffee, tea, cola drinks, chocolate on days of Study Visits 1-21
• Intake of alcohol, caffeine or strenuous exercise within 72 hours prior to study drug administration or intake of grapefruit within 7 days prior to the administration of study drug
• Intake of alcohol within 4 hours of spirometry; smoking within 1 hour of spirometry; performing vigorous exercise within 30 minutes of spirometry; wearing clothing that substantially restricts full chest and abdominal expansion; or eating a large meal within 2 hours of spirometry
• Administration of any over the counter (OTC)/prescription medication, supplements, herbals or vitamins within 14 days prior to study drug administration. Administration of Tylenol within 72 hours of study drug administration (doses up to 2g/day will be allowed prior to 72 hours before study drug administration)
• Exposure to any investigational agent within 30 days prior to the Screening Visit
• Receipt of a flu vaccine in the last 3 months
• Prior exposure to PUL-042
• Known positive for human immunodeficiency virus, or on active anti-retroviral therapy and known hepatitis B surface antigen positive or hepatitis C positive](streamdown:incomplete-link)