Impact of capsule selection on formulation stability in dry powder inhalers (DPIs)

The delivery of inhalation-based formulations is achieved by devices that fall into three segments: nebulizers, metered dose inhalers (MDIs), and dry powder inhalers (DPIs).2 There is much discussion about which device is most appropriate, though that discussion is well beyond the scope of this article. It is of note however, that MDIs and DPIs have been shown to function equally well when patients were treated with acute systems of COPD.3 DPIs seem to be a popular choice among patients who can better coordinate dosing with their personal breathing pattern.4 They tend to be both less complex and less expensive to manufacture than MDIs, especially those DPIs that use two-piece capsules as the container for the dose.