The inhalers of the future? A review of dry powder devices on the market today.

International agreements to ban the use of environmentally damaging chlorofluorocarbons (CFCs) have signalled an end to the traditional CFC-propelled pressurised metered dose inhaler (pMDI) which has long been the mainstay of topical asthma therapy. The need for acceptable and cost-effective replacement inhalers, combined with opportunities to develop generic formulations of patent-expired drugs, has fueled a lively response from the pharmaceutical industry. Improvements in pMDI design and reformulation with propellants such as hydrofluoroalkanes may offer significant advantages over CFC-pMDIs and prolong the widespread use of pressurised drug delivery systems for many years to come. In the longer term, however, another likely candidate for success in providing economical, efficient and acceptable inhaled therapies is the breath-actuated, multiple-dose dry powder inhaler (DPI). This review concentrates on the multiple-dose DPIs available within Europe today.