Inclusion Criteria:  Willing and able to give written informed consent for participation in the study. Healthy male or female subject aged ≥18 and ≤30 years inclusive. Body Mass Index (BMI) ≥18 and ≤30 kg/m2 and weight ≥50 kg to ≤100 kg at screening. Clinically normal medical history, physical findings, vital signs and laboratory values at the time of screening, as judged by the Investigator.  Exclusion Criteria:  History of any clinically significant disease or disorder (including clinically significant disease affecting the respiratory tract, thoracic deformities affecting lung function and/or lung volumes, muscle diseases affecting lung function and/or lung volumes and any known mouth or nasal passage deformities) which, in the opinion of the Investigator, may either put the subject at risk because of participation in the study, or influence the results or the subject's ability to participate in the study. Any clinically significant illness, medical/surgical procedure or trauma within two weeks prior to the first inhalation with the investigational device, which, in the opinion of the Investigator, may either put the subject at risk because of participation in the study, or influence the results or the subject's ability to participate in the study. Any positive result on screening for serum hepatitis B surface antigen, hepatitis C antibody and Human Immunodeficiency Virus (HIV).  After 10 minutes supine rest at the time of screening, any vital signs values outside the following ranges:  Systolic blood pressure > 140 mm Hg Diastolic blood pressure > 90 mm Hg Pulse < 40 or > 85 beats per minute Former regular daily smoker. Current smokers or users of nicotine products (including vaping/e-cigarettes). Irregular use of nicotine (e.g. smoking, snuffing, chewing tobacco, vaping) less than three times per week is allowed before the screening visit. FVC or FEV1 outside of normal ranges (depending on subject's gender, height and age) at screening. Female subjects who are pregnant or who are currently breast feeding. Administration of a new chemical entity (defined as a compound which has not been approved for marketing) or has participated in any other clinical study that included drug treatment with less than one month before the first inhalation session. History of severe allergy/hypersensitivity or ongoing allergy/hypersensitivity (including pollen allergy), as judged by the Investigator. History of hypersensitivity to drugs with a similar chemical structure or class to fluticasone or salmeterol, as judged by the Investigator. Positive screen for drugs of abuse or alcohol at screening or on admission to the research unit prior to any of the inhalation sessions. Current or history of alcohol abuse and/or use of anabolic steroids or drugs of abuse. Plasma donation within one month of screening or blood donation (or corresponding blood loss) during the three months prior to screening. Investigator considers the subject unlikely to comply with study procedures, restrictions and requirements.