Pharmacokinetics of Inhaled Monodisperse Fluticasone Propionate

The clinical trial is to investigate the pharmacokinetic effects (that is how much drug is in the blood) of Fluticasone Propionate (Flixotide), a commonly used steroid drug that is inhaled in patients with asthma. We will use standard clinical Flixotide Nebules that are used with clinical nebulisers (machines used in hospital and at home - to deliver drug to patients with asthma). Current clinical nebulisers deliver a 'coarse' mist of drug, which has the potential for side effects and this is an important consideration with steroids. These Flixotide nebules will be used to deliver the drug (fluticasone propionate) as monodisperse aerosol clouds (that is the drug will be delivered as a 'fine' mist cloud to patients). In order to deliver the drug as a monodisperse aerosol, the Flixotide Nebules will be used with a spinning top aerosol (a large research nebuliser machine)which is able to selectively generate aerosol clouds that have a fine mist. A fine mist cloud leads to less deposition in the throat of the patients and a greater control of the inhaled drug reaching the lungs, and fine mist drug clouds have the potential to reduce side effects. We will also compare this to the use of a standard routine clinical dose of a Flixotide metered-dose inhaler ( a 'press and breathe' inhaler) with a spacer (plastic bubble on the end of an inhaler) delivered to patients.