Well known environmental issues have led to the legislated discontinuation of the propellent used in the metered dose inhaler (MDI) formulations. The CFC propellant is being replaced with hydrofluoroalkane-134a (HFA), under FDA mandate. The current study does not address clinical effectiveness, but proposes to measure the quantitative regional pulmonary delivery of the active ingredient (TAA) in two different HFA formulations. This will allow us to compare the distribution from these formulations to each other and to the distribution which we previously measured in studies which used the original formulation with CFC propellant. The objectives of this study are: 1) To evaluate the biodistribution of triamcinolone acetonide in the oral cavity, trachea, bronchial passages and lungs as a function of time after oral inhalation of Azmacort-HFA (75 and 225) according to package directions. 2) To compare the observed time-dependent distribution achieved with the different HFA formulations to each other and to previous data obtained using Azmacort (formulated with CFC). The study follows an open label, non-randomized, crossover design of eight normal volunteers studied with PET. Administration of the 75 or 225 formulation of Azmacort-HFA will be randomized according to the volunteer's hospital-assigned ID numbers (even or odd). In a second scan session drug will be administered using the other formulation, but in otherwise identical fashion. The field of view of the PET camera is approximately 15 cm in the axial direction. However, the region of interest for determination of drug distribution extends from the oral cavity to the diaphragm, a distance which may be over 50 cm. A previous study indicated that three bed positions must be used to satisfactorily cover the area of interest. The three regions will be scanned in sequence throughout a 90 min scan period. Venous blood samples will be taken during the study for later analysis of the amount of drug which enters the bloodstream. Patients begin the study in the PET facility, and blood levels are completed on the GCRC.
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