Inhaled corticosteroid delivery systems: clinical role of a breath-actuated device

Several devices have been developed to overcome the need to co-ordinate actuation with inhalation required during use of a pressurised metered dose inhaler (MDI) and to improve drug delivery to the lung. These include spacer attachments for MDIs, dry powder inhalers and breath-actuated MDIs. The breath-actuated Autohaler (3M Pharmaceuticals) is a compact, multidose inhaler device that, unlike dry powder inhalers, does not rely on the patient's inspiratory effort to aerosolise the dose of medication. Due to its simple operation, the Autohaler is suitable for patients unable to operate a conventional MDI efficiently, including the elderly, children, patients with arthritis and patients with low inspiratory flow rates. The mandatory replacement of chlorofluorocarbon propellants with non-ozone-depleting propellants has given the opportunity to improve drug delivery characteristics of MDIs. Recently, a formulation of beclomethasone dipropionate in hydrofluoroalkane-134a (HFA-BDP), has been developed in a conventional MDI that delivers most of the emitted dose to the lung. Drug deposition studies show that the HFA-BDP formulation in the Autohaler device has a similar lung deposition pattern to drug delivered from the MDI, when used correctly, and dose delivery is consistent across a wide range of inspiratory flow rates. Furthermore, HFA-BDP Autohaler has similar clinical benefits to CFC-BDP Autohaler but at less than half the dose. HFA-BDP Autohaler offers a useful CFC-free delivery option for patients challenged by the conventional MDI device.