Background Valved holding chambers (VHCs) are not interchangeable. Because VHC design and formulation type influence aerosol behaviour, each VHC–drug combination should be evaluated to inform clinical use and device selection. Aim To compare the aerodynamic particle size distribution (APSD) of two inhaled corticosteroids delivered from pressurised metered dose inhalers with and without commonly used VHCs under realistic, adult-representative breathing. Methods We assessed fluticasone propionate (FP, suspension) and ciclesonide (CIC, solution) using no VHC and three VHCs (AeroChamber, EasyChamber and OptiChamber Diamond). A Next Generation Impactor was connected to an anatomically representative adult throat model and a breathing simulator generating an adult-type inhalation profile. Results Without a VHC, throat deposition was high. With any VHC, throat deposition fell to only a few per cent of the label claim for both FP and CIC. The 1–5 µm respirable fraction was approximately one-third of the label claim for both drugs, irrespective of VHC use, while CIC generated a larger submicron fraction than FP. Small statistically significant differences between VHCs were observed, but absolute differences in APSD and throat deposition were modest. Conclusions In adult-representative conditions, VHCs substantially reduce oropharyngeal deposition but do not influence fine-particle delivery. Differences between the tested VHCs were minor and unlikely to be clinically meaningful, whereas FP and CIC showed distinct APSD profiles consistent with formulation type. These findings support performance-based, drug-specific evaluation of VHCs and underscore the value of systematic in vitro testing to guide evidence-based spacer–drug selection and to reduce throat deposition in clinical practice.
Csonka et al. (Wed,) studied this question.