In vitro and clinical characterization of the valved holding chamber AeroChamber Plus® Flow-Vu® for administrating tiotropium Respimat® in 1–5-year-old children with persistent asthmatic symptoms

When characterizing inhalation products, a comprehensive assessment including in vitro, pharmacokinetic (PK), and clinical data is required. We conducted a characterization of tiotropium Respimat® when administered with AeroChamber Plus® Flow-Vu® anti-static valved holding chamber (test VHC) with face mask in 1–5-year-olds with persistent asthmatic symptoms. In vitro tiotropium dose and particle size distribution delivered into a cascade impactor were evaluated under fixed paediatric and adult flow rates between actuation and samplings. The tiotropium mass likely to reach children's lungs was assessed by tidal breathing simulations and an ADAM-III Child Model. PK exposure to tiotropium in preschool children with persistent asthmatic symptoms (using test VHC) was compared with pooled data from nine Phase 2/3 trials in older children, adolescents, and adults with symptomatic persistent asthma not using test VHC. At fixed inspiratory flow rates, emitted mass and fine particle dose decreased under lower flow conditions; dose reduction was observed when Respimat® was administered by test VHC at paediatric flow rates. In