Improved airway targeting with the CFC-free HFA-beclomethasone metered-dose inhaler compared with CFC-beclomethasone

Hydrofluoroalkane-134a (HFA) beclomethasone dipropionate (BDP) was formulat ed in a metered-dose inhaler (MDI) to deliver a particle size of I,I pm com pared with 3.5 microns for currently marked chlorofluorocarbon (CFC)-BDP pr oducts. Two phase I single-dose human deposition studies were conducted usi ng technetium 99m-radiolabelled BDP in a press-and-breathe actuator without an add-on spacer. A healthy volunteer study (n=6) showed that 55-60% of the HFA-BDP ex-actuat or dose was deposited in the lungs, with 29-30% deposited in the oropharynx .. CFC-BDP deposition was 4-7% in the lungs and 90-94% in the oropharynx. T he pattern of deposition within the lung showed that HFA-BDP was spread dif fusely throughout the lung airways, whereas CFC-BDP was confined to the cen tral airways with little, if any, peripheral airway deposition. A second st udy with asthmatics (n=16) confirmed that 56% of the HFA-BDP dose was depos ited in the airways, with 33% in the oro-pharynx. In conclusion, hydrofluoroalkane-134a-beclomethasone dipropionate depositio n was much greater in the airways than chlorofluorocarbon-beclomethasone di propionate, with a concomitant reduction in oropharyngeal deposition. The i ncreased lung deposition efficiency of the hydrafluoroalkane propellant has led to a reduction in the amount of bedomethasone dipropionate needed to a chieve a similar efficacy. The penetration of the hydrofluoroalkane to the small airways may provide asthma treatment not afforded by conventional chl orofluorocarbons.