Improved targeting of beclomethasone diproprionate (250 mu g metered dose inhaler) to the lungs of asthmatics with the Spacehaler (TM)

The Spacehaler(TM) (Evans Medical Ltd, Leatherhead, U.K.) is a new, compact , inhaler device containing the same aerosol canister as a conventional met ered dose inhaler (MDI). However, the design of the Spacehaler(TM) has been shown to reduce the velocity of the aerosol; thus reducing the proportion of non-respirable particles delivered to the patient. This study compared r adioaerosol deposition patterns following inhalation of 250 mu g of beclome thasone dipropionate from the Spacehaler(TM) and a conventional MDI (Beclaz one(TM), Norton Health Care, Harlow, U.K.). After rigorous in vitro validation of the radiolabelling technique, 12 asth matic subjects (seven men aged 20-69 years, mean baseline FEV1 2.59 1 (SD 0 .55 1) received one dose of Tc-99m-labelled beclomethasone dipropionate 250 mu g via either a Spacehaler(TM) or MDI on each of two study days in a ran domized cross-over manner. All subjects had been taught the required inhala tion technique before the dose was administered. Inhalation details were re corded using a spirometer connected in series with the device. Lung and oro pharyngeal depositions were measured by gamma scintigraphy. The mean percentage of the metered dose deposited in the lungs was 23.0% (S D 8.3%) for the Spacehaler(TM) and 12.8% (SD 6.8%) for the MDI (P<0.01). Ho wever, there was no significant difference in the distribution patterns wit hin the lungs between the two devices. Oropharyngeal deposition was signifi cantly lower (P<0.01) for the Spacehaler(TM) than for the MDI [mean (SD) 27 .9% (16.4%) and 73.6% (8.7%), respectively] whilst the percentage of the me tered dose remaining on the Spacehaler(TM) actuator was significantly great er than that on the MDI actuator [mean (SD) 48.0% (11.8%) and 12.4% (8.5%) respectively, P<0.01]. There was evidence from the inhalation recordings th at some patients experienced the 'cold Freon effect' whilst using the meter ed dose inhaler which may have contributed to the lower lung deposition see n with this device. This study demonstrates that the proportion of a 250 mu g dose of beclometh asone dipropionate that is delivered to the lungs is significantly greater with the Spacehaler(TM) than the MDI. The Spacehaler(TM) also reduces the p roportion of the does that is deposited in the oropharynx to less than half that observed with the MDI, and reduces the total dose of drug received by the patient.