Diskus/accuhaler

Cater, J.I., Vare, M., Peters, W.J., Olsson, B., and Gomez, E., Comparison of the efficacy of fluticasone propionate given twice daily via the Diskus /Accuhaler and the Diskhaler in patients with asthma, Eur. Resp. J., 8 427S (1995). 

Diskus / Accuhaler Glaxo SmithKline Passive Lactose Blister Multiple unit-dose 60... 

Figure 8.7 Diskus/Accuhaler (GlaxoSmithKline) [With modifications from Crompton (1997). Reproduced with permission from Blackwell Science.]...

Diskus/Accuhaler (GlaxoSmithKline, UK) is a multidose inhaler with 60 doses the dmg is contained in blisters on a foil strip and is blended with lactose as carrier. As a blister moves toward the mouthpiece, the covering foil is pulled off it prior to inhalation. Air is sucked through the inhaler and the powder is aerosolized by shear-force fluidization. Extra air drawn through the two holes in the mouthpiece helps with particle deaggregation by providing turbulence. 

Further improvement of this principle of factory-metered blistered unit doses was achieved when GlaxoSmithKline developed the Accuhaler device (also named Diskus in some countries (Fig. 8.7). This multiple-dose DPI device contains a blister strip of 60 unit doses that is transported to the next filled unit dose by pulling a small ergonomic lever prior to inhalation. The powder is presented for aerosolization by peeling back the foil from the blister, which is superior to simple piercing because it is not associated with variability in foil flap shape and device retention. The dose indicator on top of the device tells the patient how many doses are left and decreases each time the lever is pulled. This means that as with most other devices, operation of the dose indicator is associated with the loading operation and not with the inhalation maneuver. 

Dry-powder aerosol delivery offers yet another set of challenges from an in vitro/in vivo correlation perspective. There are two main types of dry-powder inhaler those that are passive and rely on the patient s inspiratory effort to generate the aerosol and those that are active and use some form of internal power source. Examples of the former would be the Turbuhaler, Accuhaler/Diskus, and the Uke. Examples of the latter are the Dura Spiros and the Inhale pulmonary delivery system. Characterizing the aerosol clouds generated by these devices in a manner usefiil for deposition predictions can require different experimental approaches. 

---