The use of inhalation profiles for testing the realistic aerosolization of the emitted dose from inhalers has been reported. High inter-patient and inter-device variability in the inhalation parameters of patients has been previously identified. The aim of this study was to employ a patient-centred pharmaceutical characterisation approach to assess the performance of a cyclone spacer for a Cyclohaler through collecting and ranking (as percentiles of the peak inspiratory flow (PIF) populations) the inhalation profiles of human volunteers through the spacer; and subsequently performing in vitro testing using an inhalation simulator. The aerosolization of cohesively- and adhesively-balanced blends was compared using full inhalation profiles and the peak inspiratory flow. However, the steady flow was an inadequate metric to assess inter-subject variability in fine particle delivery from a dry powder inhaler (e.g. for salmeterol xinafoate (SX) the throat deposition was 27.89 ± 3.32% at 25% and 25.45 ± 3.08% at 90%, respectively). A lower fine particle fraction (FPF) calculated as inhaler-emitted dose was measured for SX blends compared to salbutamol sulphate (SS) blends (e.g. at median PIF 19.23 ± 3.93% versus 14.61 ± 2.38%), due to the higher throat deposition of SX. However, when using the inhalation profiles, higher doses of SX were emitted from the cyclone than SS. The current study showed the potential use of spirometer technology to collect inhalation profiles for patient-centred device testing. A full assessment of new (or generic) device functionality requires simulation of real-life inhalation conditions.