A Study of the Safety and Tolerability of a Single Dose Administration of CVT-301 (Levodopa Inhalation Powder)

Inclusion Criteria: * 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 * diagnosis of Parkinson's disease and motor fluctuations and early morning OFF symptoms * classified as Stage 1 to 3 on the modified Hoehn and Yahr scale for staging of PD severity (in an ON state) * subjects who are on a l-dopa-containing therapy, not including Rytary (or equivalent), must be stable on oral l-dopa-containing therapy for at least 2 weeks prior to the Screening Visit with a l-dopa/decarboxylase inhibitor (DDI)-containing regimen * subjects who are on a l-dopa-containing therapy, when including Rytary (or equivalent), should be on a stable dose for at least 6 weeks prior to the Screening Visit * the frequency of l-dopa administrations must be at least 3 times during the waking day and a total daily l-dopa dose of ≤ 1600 mg. * on a stable regimen of their standard PD medications * on a stable regimen of any blood pressure reducing medications (if applicable) for at least 30 days prior to screening * forced expiratory volume in one second (FEV1) ≥60% of predicted for race, age, sex, and height and FEV1/FVC (forced vital capacity) ratio ≥70% * no clinically significant abnormalities that would affect ability to complete study as determined by medical history, physical examination, electrocardiogram, clinical laboratory test results * negative drug and alcohol testing * negative pregnancy test for all women. Exclusion Criteria: * participated in any prior study with CVT-301 * dyskinesia of a severity that would significantly interfere with the subject's ability to participate or perform study procedures (as determined by the UPDRS Part 4) * any contraindication to performing routine spirometry or who are unable to perform a spirometry maneuver * have a current history of symptomatic orthostatic hypotension or are treated with medications to treat orthostatic hypotension (for example droxidopa, fludrocortisone), if they have severe dysautonomia * have chronic obstructive pulmonary disease (COPD), asthma, or another chronic respiratory disease within the last 5 years.