The influence of carrier shape and surface roughness of carrier based dry powder inhalates on the fine particle fraction

 

The influence of carrier shape and surface roughness of carrier-based dry powder inhalates on the fine
particle fraction

Summary
The aim of this work was to study the influence of carrier shape and surface roughness on the fine particle
fraction of carrier based dry powder inhaler formulations. Carrier particles of different roughness and shape were
prepared by spray drying of aqueous mannitol solutions at different outlet temperatures. Subsequently ordered
mixtures of micronized salbutamol sulphate and the carriers of different roughness and shape were prepared. It
could be shown that the highest fine particle fraction (FPF) is achieved for rough, spherical particles (FPF = 29.23
%, Ra = 140.33, Aspect ratio = 0.925, M67). A decrease in surface roughness (Ra = 88.73) leads to lower FPFs
(FPF = 14.62 %, Aspect ratio = 0.918, M80). This study further shows that the fine particle fraction is influenced
by the particle shape. During mixing the micronized active cumulates within cavities of irregular shaped carrier
particles. Upon inhalation the cavities may impede the detachment of the active from the carrier upon inhalation
and the fine particle fraction decreases.

19.Littringer