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This study compared the dose delivery and cascade impaction performance, including mass median aerodynamic diameter (MMAD) and respirable dose (RD), of four metered-dose inhaler (MDI) and spacer combinations (Aerobid ® and AeroChamber ® , Beclovent ® and Ellipse ® , Venceril ® and InspirEase ® , and Vanceril and Microspacer ® ). Dose delivery and cascade impaction samples were collected under the following conditions: with and without the spacer, with and without a 5-second delay between actuation and start of airflow, and at airflow rates of 12.5 and 40.0 L/min (for dose delivery only). Testing conditions reproduced conditions specified in the patient package inserts as closely as possible. Under all test conditions, the spacers reduced the dose delivery from the MDI. When no delay was used and the flow rate was set at 12.5 L/min, the dose delivered compared with no spacer was 26.7% for the Microspacer, 36.2% for the AeroChamber, 36.7% for InspirEase, and 81.0% for the Ellipse. When a delay was added at the same flow rate, the dose delivery was further reduced to 23.8% for the Microspacer, 27.4% for the AeroChamber, 31.6% for the InspirEase, and 65.8% for the Ellipse. The InspirEase without a time delay showed a sensitivity to the increase in flow rate as the dose delivered increased from 36.7% to 49.1%. The MMAD decreased when the AeroChamber, InspirEase, and the Microspacer were added to the MDI and no time delay was used. In each case, a further reduction in the MMAD occurred when a time delay was introduced. With the Ellipse spacer, MMAD increased when no delay was used and decreased when a delay was used. The RD (fraction of particles |
