Crossover Study to Investigate the Safety, Tolerability, and Pharmacokinetics of Repeat Dose Zanamivir/Placebo Via Devices Administered Twice Daily for 5 Days

Inclusion Criteria: * The subject is healthy as judged by a responsible physician with no clinically significant abnormality identified on a medical evaluation * Male and female volunteers from 18-55 years of age, inclusively, at the time of signing the informed consent. * A female subject is eligible to participate if she is of: Non-childbearing potential defined as pre-menopausal females with a documented tubal ligation or hysterectomy; or postmenopausal defined as 12 months of spontaneous amenorrhea or Child-bearing potential and agrees to use one of the contraception methods listed in the protocol for an appropriate period of time (as determined by the product label or investigator) prior to the start of dosing to sufficiently minimize the risk of pregnancy at that point. * Male subjects must agree to use one of the contraception methods listed in the protocol. * Nonsmokers defined as abstinence from cigarette smoking for the previous 12 months before enrollment into the study. * Body mass Index of 19-30 kg/m2. * FEV1 greater than or equal to 85 percent of the predicted and FEV1/FVC ratio greater than or equal to 0.7 at screening. * Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the consent form. Exclusion Criteria: * The subject has a positive pre-study urine drug/ alcohol screen. * Significant pulmonary disease, such as chronic obstructive pulmonary disease, asthma, or other pulmonary diseases th…