Understanding Flow Rate Influence on Clip-Tone Guided Inhaler Delivery



Clip-ToneÒ is a novel add-on to a pressurised metered dose inhaler (pMDI) that provides the patient with an acoustic whistle signal during their use of the inhaler. The signal, which sounds between 20 and 48 L.min-1, is intended as a guide to help patients establish good inhaler technique in respect of inspiratory flow rate, coordination and duration of inhalation. It is important to understand whether such devices have an impact on inhaler delivery performance. We have conducted a series of assessments to determine any effects: these have included aerosol particle size determinations (APSD) and aerosol characteristics at three flow rates (20, 30 and 48 L.min-1; the range of the acoustic signal) and plume geometry assessment at 30 L.min-1. All assessments were made with standard VentolinÒ EvohalerÒ (100mg salbutamol, GSK) with and without (Control) the Clip-Tone device. Fine particle fraction data (%<5µm) at 20, 30 and 48 L.min-1 for Control were 27.5±2.0, 48.9±1.3 and 43.8±2.9 respectively; for pMDI plus Clip-Tone: 30.0±1.7, 48.2±1.6 and 44.9±1.6. Similarly, fine particle dose data (µg<5µm) were Control: 27.8±3.5, 39.8±1.9 and 46.3±7.1 and pMDI plus Clip-Tone: 31.0±2.0, 41.5±2.5 and 40.9±3.1. Summary APSD data were comparable. Mean spray velocity and plume angle were not different between the test groups: 64.6±4.9 m.second-1 and 10.2°±4.8 for Control and 63.8±6.7 m.second-1 and 11.5°±5.7 for pMDI with Clip-Tone, respectively: any variation in results between tests conducted was less than the natural spray-to-spray variability of the inhaler. APSD, aerosol characteristics and plume geometry have demonstrated that the Clip-Tone inhaler technique guidance device is without effect in vitro on aerosol delivery.

Key Message

Inhaler technique is of paramount importance. A new acoustic-signal tool that encompasses training for flow rate, coordination and duration, and is for continual use (ie. during drug administration) is without effect in vitro on aerosol characteristics while the signal sounds and does not affect the aerosol plume.

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