$MNKD Ran across this, and just sharing. It's a pretty dry read, so I'll help by giving you the highlights: 1. "In relation to the administration of an inhalation product with systemic activity (Afrezza®, MannKind, Westlake Village, CA, USA), a human insulin inhalation powder employing a small and easy-to-use dry powder inhaler was approved in 2014 by the FDA for type 1 and type 2 diabetes mellitus patients." 2. "Notably, due to the increased pressure drop across the device, high resistance DPIs tend to produce a greater lung deposition than those with low intrinsic resistance [12]. Namely, the increase in resistance means that low air flow rates are reached inside the inhaler, and this leads to particles which, given their relative low speed, are less subject to impact mechanisms in the upper airways."