Pharmacokinetic Study of CVT-301 (Levodopa Inhalation Powder)

Inclusion Criteria: * Men and women between the ages of 30 and 85 years, inclusive. * Have idiopathic PD (i.e., not induced by drugs or other diseases) as defined by fulfilling Steps 1 and 2 of the United Kingdom (UK) Brain Bank criteria, diagnosed after the age of 30 years. * Classified as Stage 1 to 3 (in the ON state) on the modified Hoehn and Yahr scale for staging of PD severity. * Stable on other non levodopa PD medications for at least 4 weeks prior to the Screening Visit. * Subjects must have normal cognition as confirmed by a score of ≥ 25 on the Mini Mental State Examination (MMSE), performed in the ON state. * Forced expiratory volume in one second (FEV1) ≥60% of predicted for race, age, sex, and height and FEV1/FVC (forced vital capacity) ratio ≥70%. * Body Mass Index (BMI) between 18 - 32 kg/m2, inclusive. Exclusion Criteria: * Any flu-like syndrome or other respiratory infections within 2 weeks prior to the Screening Visit. * Chronic obstructive pulmonary disease (COPD), asthma, or other chronic respiratory disease within the last 5 years. * History of any cancer in the past 5 years with the exception of successfully treated basal cell carcinoma. * Narrow angle glaucoma or a history of peptic ulcer disease less than 1 year prior to screening. * Previous surgery for PD (including but not limited to deep brain stimulation or cell transplantation). * Current use of nicotine patch or tobacco-containing products including cigarettes, electronic cigarettes, cigars, chewing tobacco, pipe tobacco or snuff or use within 4 weeks prior to the Screening Visit, or expected use during the study. * Marijuana smoking within 4 weeks prior to the Screening Visit, or expected smoking/inhalation during the study.