Objectives of the study are to investigate the safety, tolerability and levels of ciprofloxacin in the lung after single and multiple inhalative administration to patients with mild to moderate COPD (stage I-II according to GOLD Criteria).

Inclusion Criteria:

• Adult patients with COPD (Stage I or II according to the GOLD Classification), 35 years of age or older
• Airway obstruction with a post-bronchodilator Forced Expiratory Volume (FEV1) > or equal 50% of predicted normal and a post-bronchodilator FEV1 / Forced Vital Capacity (FVC) < 70%.
• Current or ex-smokers with a smoking history of more than 10 pack-years
• Body mass index (BMI) between 18 and 33 kg/m2
• Written informed consent to participate in the study after receiving adequate previous information and prior to any study specific procedures

Exclusion Criteria:

• Significant disease other than COPD as bronchial asthma, cystic fibrosis or clinically evident bronchiectasis
• Total blood eosinophil count >/=600/mm3.
• Thoracotomy with pulmonary resection
• Regular use of daytime oxygen therapy
• Completion of a pulmonary rehabilitation program in the six weeks prior to the pre-study examination or current participation in a rehabilitation program
• Hypersensitivity to the investigational drug or to other quinolones and/or to inactive constituents of the inhalation powder
• Hypersensitivity of the bronchial system to inhalation of nebulized drugs or saline solution
• Acute pulmonary exacerbation
• Patients with a history of severe allergies, non-allergic drug reactions, or multiple drug allergies
• Concomitant inhalative therapy with antibiotics and/or concomitant systemic therapy with fluoroquinolones
• Oral beta-adrenergics, beta blockers
• Long acting anti-cholinergics within 2 weeks prior to pre-study examination
• Inhaled or oral steroids
• Methylxanthines: 24-hour washout of short-acting theophylline and 48-hour washout of long-acting theophylline prior to pre-study examination
• Antihistamines, antileukotrienes prescribed for asthma
• oral cromolyn sodium or oral nedocromil sodium