Improving usability and maintaining performance: human-factor and aerosol-performance studies evaluating the new reusable Respimat inhaler

Figures & data

Table 1 Operating elements of Respimat and reusable Respimat

	Intended action/feature	Disposable Respimat	Reusable Respimat
Mouthpiece	Fits to patient’s mouth	Present	Unchanged
Air vents	Entrance of air for inhalation	Present	Unchanged
Dose-release button	Triggers delivery of aerosol	Present	Unchanged
Cap	Protects mouthpiece against dust	Present	Unchanged
Device lock	Limits use within safe (and checked) bounds	Present, nonreversible	Modified to reversible; new or not used-up cartridge resets device lock
Cartridge counter	Monitors end of specified inhaler life span	Not implemented	New, indicates used-up device
Cartridge lock	Limits use within safe (and checked) bounds	Not implemented	New, locks device when cartridge is used up
Dose indicator	Indicates remaining number of actuations and prevents normal use after end of specified cartridge life span	Present on inhaler body	Modified, now present on cartridge
Safety catch	Keeps clear base in position	Present	Modified, releases automatically when cartridge is locked
Cartridge	Container for aqueous drug solution	Present	Unchanged, but dose indicator added
Clear base	Grip for cocking inhaler, covers bottom part of device, provides view on device label and dose indicator	Present	Modified to receive enlarged dose counter and triggers dose indicator
Piercing element	Opens foil in order to vent the cartridge	Present	Integrated inside counter

Figure 1 Respimat design features.

Notes: (A) Disposable vs reusable; (B) dose indicator showing remaining number of actuations; (C) cartridge counter to monitor end of specified inhaler life span.

Figure 2 Delivered dose uniformity of (A) olodaterol and (B) tiotropium for nine cartridges in the reusable Respimat.

Notes: The reference disposable Respimat inhaler is shown in the leftmost panel. For each cartridge used in a reusable Respimat, data at start (left row) and end (right row) of cartridge are given. Each colored dot represents mean value for one dose; single gray dots at the right of each cartridge panel represent means of respective cartridge in relation to the label claim. Lines represent 15% (solid line), 25% (dots), and 35% (dashes) deviation from the reference. Mean data from ten inhalers are shown.

Figure 3 Fine-particle fraction for use of nine cartridges of tiotropium–olodaterol in the reusable Respimat inhaler determined by laser diffraction.

Notes: Gray bars represent a disposable inhaler batch as reference. Dark-blue bars represent the reusable inhaler used with nine cartridges. Mean values for individual inhalers (n=3) are shown. Correlating cutoff sizes of the Andersen cascade impactor were (µm): stage 0, >9.0; stage 1, 9.0–5.8; stage 2, 5.8–4.7; stage 3, 4.7–3.3; stage 4, 3.3–2.1; stage 5, 2.1–1.1; stage 6, 1.1–0.7; stage 7, 0.7–0.4; and filter, <0.4.

Abbreviation: SIP, sample induction port.

Figure 4 Aerodynamic particle-size distribution for use of nine cartridges of tiotropium–olodaterol in the reusable Respimat inhaler determined by the Andersen cascade impactor.

Notes: Olodaterol (top graphic) and tiotropium (bottom graphic). Cutoff sizes of the Andersen cascade impactor were (µm): stage 0, >9.0; stage 1, 9.0–5.8; stage 2, 5.8–4.7; stage 3, 4.7–3.3; stage 4, 3.3–2.1; stage 5, 2.1–1.1; stage 6, 1.1–0.7; stage 7, 0.7–0.4; filter, <0.4.
Abbreviations: LC, label claim; MA, mouthpiece adapter; SIP, sample induction port.

Figure 5 Overall perceived ease of performing cartridge insertion.

Note: Scoring from −7 (favors disposable Respimat) to +7 (favors reusable Respimat).

Figure 6 Rating of the clear base-detaching mechanism.

Note: Scoring from 1 (does not apply at all) to 7 (applies completely).

Figure 7 Rating of ease of exchanging a refill cartridge.

Note: Scoring from 1 (very difficult) to 7 (very easy).

Figure S1 Particle-size distributions of tiotropium, olodaterol, and tiotropium–olodaterol by (A) laser diffraction and (B) Andersen cascade impactor.

Notes: Data are means of stability batches. For tiotropium–olodaterol Respimat, the particle-size distribution of tiotropium and olodaterol is shown. Correlating cutoff sizes of the Andersen cascade impactor were (µm): stage 0, >9.0; stage 1, 9.0–5.8; stage 2, 5.8–4.7; stage 3, 4.7–3.3; stage 4, 3.3–2.1; stage 5, 2.1–1.1; stage 6, 1.1–0.7; stage 7, 0.7–0.4; and filter, <0.4.

Abbreviations: Olo, olodaterol; SIP, sample induction port; T/O, tiotropium–olodaterol; Tio, tiotropium.

Figure S2 Delivered dose uniformity of (A) olodaterol and (B) tiotropium within reusable tiotropium–olodaterol Respimat for 15 cartridges.

Notes: Lighter columns, cartridges 1–9 (in-use testing); darker columns, cartridges 10–15 (sequential testing after 12 months’ nonuse). For each cartridge, the individual values at the start and the end of the testing schedule are given as a percentage referring to the average of all individual values, and the mean value is given as a percentage referring to the target dose.

Figure S3 Particle-size distribution (Andersen cascade impactor) of tiotropium–olodaterol reusable Respimat for 15 cartridges.

Notes: Lighter columns, cartridges 1–9; darker columns, cartridges 10–15; upper panel, olodaterol; lower panel, tiotropium. Cutoff sizes of the Andersen cascade impactor were (µm): stage 0, >9.0; stage 1, 9.0–5.8; stage 2, 5.8–4.7; stage 3, 4.7–3.3; stage 4, 3.3–2.1; stage 5, 2.1–1.1; stage 6, 1.1–0.7; stage 7, 0.7–0.4; and filter, <0.4.

Abbreviations: API, active pharmaceutical ingredient; MA, mouthpiece adapter; SIP, sample induction port.

Figure S4 Effect of cleaning frequency on delivered volume of tiotropium–olodaterol.

Notes: Mean values of nine Respimat inhalers of three batches; error bars = relative SD.

Figure S5 Effect of cleaning frequency on delivered dose of tiotropium–olodaterol.

Notes: Mean values of nine Respimat inhalers of three batches; error bars = relative SD.

Abbreviation: LC, label claim.