A Dose-Range Finding Study of SUN-101 in Subjects With Moderate to Severe COPD

Inclusion Criteria: 1. Male or female patients 40 to 65 years-old, inclusive. 2. A clinical diagnosis of moderate to severe COPD according to the GOLD 2011 guidelines. 3. Current smokers or ex-smokers with at least 10 pack year smoking history (eg, at least 1 pack/day for 10 years, or equivalent). 4. Post bronchodilator (following inhalation of ipratropium bromide) FEV1 ≥ 40% and ≤ 70% of predicted normal during Screening. 5. Post bronchodilator (following inhalation of ipratropium bromide) FEV1/FVC ratio ≤ 0.70 during Screening. 6. Post bronchodilator (following inhalation of ipratropium bromide) improvement in FEV1 ≥ 12% and ≥ 100 mL during Screening. 7. Ability to perform reproducible spirometry according to the American Thoracic Society (ATS) and European Respiratory Society (ERS) guidelines (2005). 8. Female of child bearing potential (only) must have a negative serum pregnancy test at Screening and be neither breastfeeding nor intending to become pregnant during study participation. Females of childbearing potential must be instructed to and agree to avoid pregnancy during the study. Female subjects of child bearing potential must use an adequate method of birth control from Screening until 30 days after receiving study drug and use contraception in addition to their partners using a barrier method. Acceptable forms of contraception are as follows: * Abstinence * Barrier methods: condoms, diaphragms, cervical caps; with a spermicide foam, gel, film, cream or suppository; * Oral contraceptives * Non hormone containing intrauterine methods: intrauterine devices or systems. 9. Willing and able to remain at the study site for at least 24 hours at Day 7 of each Treatment Period. 10. Willing and able to attend all study visits and adhere to all study assessments/procedures. 11. Willing and able to provide written informed consent Exclusion Criteria: 1. Current evidence or recent history of any clinically significant and unstable disease (other than COPD) or abnormality in the opinion of the Investigator that would put the subject at risk or which would compromise the quality of the study data; including but not limited to cardiovascular disease, myocardial infarction, cardiac failure, uncontrolled hypertension, life threatening arrhythmias, uncontrolled diabetes, neurologic or neuromuscular disease, liver disease, gastrointestinal disease or electrolyte abnormalities. 2. Current evidence or history of a clinically significant abnormality of cardiac rhythm and/or conduction including Holter monitoring prior to randomization. 3. Primary diagnosis of asthma. 4. History of malignancy of any organ system, treated or untreated within the past 5 years, with the exception of localized basal cell carcinoma of the skin. 5. Recent history of COPD exacerbation requiring hospitalization or need for increased treatments for COPD within 6 weeks prior to Screening. 6. Use of daily oxygen therapy \> 10 hours per day. 7. Use of systemic steroids within 3 months prior to Screening. 8. Respiratory tract infection within 6 weeks prior to or during Screening. 9. History of tuberculosis, bronchiectasis or other non-specific pulmonary disease. 10. History of urinary retention or bladder neck obstruction type symptoms. 11. History of narrow angle glaucoma. 12. Prolonged QTcF interval (males \> 450 msec and females \>470 msec) during Screening, or history of long QT syndrome. 13. Recent history (previous 12 months) of excessive use or abuse of alcohol or narcotic/illegal drugs. 14. History of hypersensitivity or intolerance to aerosol medications, beta-2 agonists, or anticholinergics. 15. Participation in another investigational drug study where drug was received within 30 days prior to Screening, or current participation in another investigational drug trial. 16. Subject is a staff member of the clinical site or a relative of a clinical site staff member.