Imagine the Superiority of Dry Powder Inhalers from Carrier Engineering
Table 1
Hypotheses and working mechanism of “addition of lactose fines” [6, 7].
Hypothesis
Working mechanism
Active sites hypothesis
Fines engage so-called “active sites” (more adhesive sites) on carrier surface, leaving only weaker binding sites (less adhesive sites) accessible for the drug particles to bind to.
Agglomeration hypothesis
Fines materialize agglomerates, multilayers with drug particles, which are hypothetically more easily isolated from the carrier surface.
Buffer hypothesis
Fines coarser than the drug particles might work as a buffer between moving carrier particles and shelter drug particles from press-on forces during mixing.
Fluidization hypothesis
Fines enhance the tensile strength of the powder mixture, which enhances the minimum fluidization velocity (MFV) required for fluidization and therefore the energy available for dispersion.
Case-dependent hypothesis
Contrary to the all above hypothesis, fines do not always enhance the aerodynamic performance of a DPI which is concluded by the formulation and dispersion situations.