Abstract
RATIONALE: Electrostatic charge mitigation by the use of charge dissipative materials with VHCs is common, since initial pre-washing can be avoided. We compared 'antistatic' VHCs; Optichamber® Diamond® (OD), Phillips Healthcare with AeroChamber Plus® Flow-Vu® (AC Flow-Vu) Trudell Medical International) (n=4 devices/group), to determine suitability for patients delaying inhalation post-actuation.
METHODS: An abbreviated Andersen impactor that determined fine particle mass < 4.7 µm at 28.3 L/min (FPM<4.7µm) was used with an apparatus simulating 2, 5 and 10 s delay intervals following pMDI actuation (Flovent®, GSK plc, 125 µg/actuation fluticasone propionate (FP)). This approach conforms to guidance from European authorities that testing of VHCs should simulate delayed inhalation. Assay for FP was undertaken by HPLC-UV spectrophotometry. Measurements without delay were undertaken to assess mass recovery for FP, validating the procedure. All values are mean±SD.
RESULTS: Mass recoveries (131.5±2.9 and 130.7±3.8 µg/actuation for the OD and ACPlus VHCs respectively) were close to label claim, validating system suitability. The variation of FPM<4.7µm with delay interval is shown in the Table.
The ratio FPM<4.7µm-ACPlus/FPM<4.7µm-OD) increased from 1.2 (2-s) to 1.4 (5-s) and to 1.6 (10-s), demonstrating faster depletion of the therapeutically beneficial medication from the OD.
CONCLUSION: Not all VHCs manufactured from anti-static materials provide optimum performance for patients who have poor coordination.
- © 2012 ERS