LUNG DEPOSITION OF SALBUTAMOL FROM THE LEIRAS METERED-DOSE POWDER INHALER

The deposition patterns of salbutamol inhaled from a new metered dose dry powder inhaler (Leiras Oy, Finland) were assessed using gamma scin tigraphy. The drug formulation was labelled with the radionuclide Tc-9 9(m), and in vitro validation experiments performed with an Andersen C ascade Impactor demonstrated that the radiolabel would act as a marker of in vivo drug distribution. Eleven healthy volunteers took part in the study, inhaling through the device at a mean (SEM) flow rate of 31 .2 (3.6) L . min(-1). The mean (SEM) whole lung deposition was 41.6 (1 .7)% of the delivered dose, and 23.9 (1.4)% of the metered dose. The d rug was distributed fairly evenly throughout the lungs with a mean rat io of peripheral/central deposition of 1.2. It was concluded that drug delivery from the Leiras dry powder inhaler was comparable or superio r to that observed for other metered dose powder inhalers.