A critical comparison of the dose delivery characteristics of four alternative inhalation devices delivering salbutamol: Pressurized metered dose inhaler, Diskus inhaler, Diskhaler inhaler, and Turbuhaler inhaler

Salbutamol is a short-acting beta(2) agonist which is effective as a rescue therapy in the treatment of asthma. This study uses in vitro test methods to compare the capability of four alternative devices to deliver an accurat e and precise dose of salbutamol. It is demonstrated that the conventional metered dose inhaler (MDI) achieves excellent accuracy and precision in dos e delivery. Additionally, it is the most efficient inhaler in terms of gene rating in-vitro a fine particle fraction from the dose. A spacer device has been shown to further enhance the dosing characteristics. When tested over a wide range of inspiratory air flow rates, the Diskus (GlaxoWellcome, Her tfordshire, UK) has comparable accuracy and precision to the MDI tested at 60 L/min, and it offers an advantage over two alternative dry powder inhale rs (DPIs), delivering a more consistent dose across the range of flow rates tested and being more efficient at generating a fine particle fraction tha n either Turbuhaler (Astra, Lund, Sweden) or Diskhaler (GlaxoWellcome) at b oth 28 and 60 L/min inspiratory flow rates. Diskus, Diskhaler, Ventolin, Vo lumatic, and Rotadisk are trademarks of the GlaxoWellcome Group of companie s. The Accuhaler is the alternative to the Diskus in those countries where the Diskus trademark is not available. Inspiryl and Turbuhaler are trademar ks of the Astra Group of companies.