Clinical use of dry powder systems.

The first successful dry powder inhalation system (Spinhaler) was introduced in 1969. The majority of patients unable to use pressurised aerosols efficiently were found to have no difficulty using the Spinhaler. The dry powder delivery system was, therefore, developed for the inhalation of a selective beta 2-agonist (salbutamol) and also beclomethasone dipropionate. The original designs of this device (Rotahaler) were found difficult to use by many patients. Recent major modifications to this device (Rotahaler Mark III) have improved it considerably and this has been confirmed in an acceptability study in 300 patients. The latest development in dry powder systems is the design of a device which is loaded with 8 capsules and is extremely simple to use. Presently dry powder systems are reserved for those patients who cannot use pressurised aerosols efficiently, but if in the future further improvements in design are made this type of delivery system may become a serious competitor to the pressurised inhaler.