GW642444 (the study medicine) is a new experimental medicine for treating asthma and chronic obstructive pulmonary disease (COPD). People with asthma and COPD suffer from breathlessness because the small tubes (bronchioles) that carry air in and out of the lungs become narrow. We hope that the study medicine will work by relaxing the muscles in the airways and help to keep the airways open, and make breathing easier. The study medicine might improve on available treatments by having fewer side-effects, and by working faster and for longer, so that patients could take it once daily, instead of twice daily.

When a medicine is made into a form ready to be given to patients, inactive ingredients are often added. Inactive ingredients might be used to help a medicine work better, to make it easier to produce the medicine, or to make it easier to get an accurate dose of medicine. In this study, the study medicine contains the inactive ingredient magnesium stearate.

We need to check that the study medicine doesn't cause problems when inhaled along with magnesium stearate. So, we're doing this study in healthy people to find out the answers to these questions.

1)Do repeated once-daily doses of the study medicine cause any important side effects when inhaled, along with magnesium stearate, as a fine powder? 2)How much of the study medicine gets into the bloodstream and how long does the body take to get rid of it?