Fourteen mild-to-moderate asthmatic patients completed a randomized four-way crossover scintigraphic study to determine the lung deposition of 200 microg budesonide inhaled from a Respimat Soft Mist Inhaler (Respimat SMI), 200 microg budesonide inhaled from a Turbuhaler dry powder inhaler (Turbuhaler DPI, used with fast and slow peak inhaled flow rates), and 250 microg beclomethasone dipropionate inhaled from a pressurized metered dose inhaler (Becloforte pMDI). Mean (range) whole lung deposition of drug from the Respimat SMI (51.6 [46-57]% of the metered dose) was significantly (p < 0.001) greater than that from the Turbuhaler DPI used with both fast and slow inhaled flow rates (28.5 [24-33]% and 17.8 [14-22]%, respectively) or from the Becloforte pMDI (8.9 [6-12]%). The deposition pattern within the lungs was more peripheral for Respimat SMI than for Turbuhaler DPI. The results of this study showed that Respimat SMI deposited corticosteroid more efficiently in the lungs than either of two widely used inhaler devices, Turbuhaler DPI or Becloforte pMDI.

In this randomised double-blind study, patients >or=40 years old with COPD, a smoking history of >or=10 pack-years, a pre-bronchodilator FEV(1) of

Although the use of pressurised aerosol inhalers is widespread, little is known about the actual deposition of the aerosol in the respiratory tract, since this has previously been difficult to measure. We have incorporated Teflon particles (mean various conditions and for assessment of theracentages of the dose deposited on the conducting airways and in the alveoli are unknown. In this paper we present the first direct measurement of the deposition of pressurised inhalation aerosols, using an objective in vivo radioactive technique. MethodsIn order to study the deposition of pressurised aerosols, we have incorporated Teflon particles (density 2'1 gm cm-3), generated by the spinning disc technique,7 into metered-dose inhalers. A fine suspension of fluorocarbon resin (Teflon 120, Dupont) in a mixture of 40% ethanol and 99mtech-netium (Tc) was delivered to the centre of the rapidly rotating disc. The particles generated (mean diameter 2 ,tm, standard deviation 0 4 ,tm) were allowed to settle onto the base of a large airtight tank inside which the generator was situated. After collection, the 99mTc was firmly sealed within the particles by heating at 2400C for five minutes.The pressurised canisters and valves used in this study were those available commercially for the delivery of terbutaline sulphate (Bricanyl, Astra Pharmaceuticals). Eight mg of the Teflon particles were placed inside an open canister, and 2 ml of 52 on 9 May 2018 by guest. Protected by copyright.

ABSTRACr The size distribution of saline and bronchodilator (terbutaline) aerosol droplets generated from four widely used jet nebulisers (Acorn, Upmist, Turret, and Inspiron Mini-neb) has been measured with a Malvern 2200 Laser Particle Sizer. The mass median diameter of aerosol droplets generated by each nebuliser was strongly influenced by the driving flow rate of compressed air. By increasing the flow rate from 4 to 81 min-' mass median diameters were halved (p < 0-01) and there was an increase in the mass of aerosol within the optimum respirable range (<5 ,m). To achieve this range the following individual flow rates were required: Turret 4 1 min-', Acorn and Upmist 6 1 min-t, and Inspiron Mini-neb 8 1 min-t. A significant inverse relation (p < 0.001) was found between mass median diameter and the geometric standard deviation, indicating that the aerosols were smaller but more heterodisperse at high flow rates. Changes in drug concentration had little effect on aerosol size. In 72% of the nebulisations followed to dryness there was no significant change in mass median diameter during the course of nebulisation and in the remainder it was less than 1-3 Am.

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