Effect of Pre-Treatment With Cromolyn or Albuterol on Response to PUL-042 Inhalation Solution (PUL-042)

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