Background: In recent years ‘anti-static’ Valved Holding Chambers (VHCs) have become more widely available. They enable use directly out of packet without pre-treatment, as pre-washing with detergent followed by drip-drying in air is time-consuming and not always followed. This laboratory study sought to investigate whether fine particle (<4.7 µm) drug delivery efficiency was similar from four commercially available VHCs, two of which were ‘anti-static’, the others being non-conducting, when pre-washing was not performed.
Materials and Methods: Each VHC (n=3 or 5/group) was evaluated with Seretide® 250 pMDI (fluticasone propionate (FP)/25 salmeterol xinafoate (SX)), sampling the emitted aerosol at 28.3 L/min via an abbreviated Andersen impactor connected to a PhEur/USP induction port. A 5 s delayed inhalation was mimicked using a proprietary apparatus. Recovered FP and SX were assayed by validated HPLC-based methods.
Results: The FPM<4.7μm for the non-conducting devices (Compact SpaceChamber Plus® and A2A™ Spacer) were greatly reduced compared with the anti-static devices with as low as 6% of the medication delivered in some cases compared to the best performing Anti-Static VHC. The two Anti-Static VHCs (AeroChamber Plus® Flow-Vu® Anti-Static VHC and OptiChamber® Diamond®) delivered consistently more medication as therapeutically beneficial FPM<4.7μm, however even for these two devices, the performance was not equivalent, with the former device exhibiting significantly higher values (1-way ANOVA, p < 0.001).
Conclusions: The results indicate that if pre-conditioning is not performed for non-conducting VHCs then there is likely to be greatly reduced medication delivered to the patient and therefore under-dosing until VHC conditioning occurs. The use of ‘anti-static’ VHCs improves the reliability of medication delivery from pMDI-VHC combinations, although there are still differences in performance, and other factors, such as chamber design can also affect the fine particle delivery. Care should be taken by prescribers in the selection of these devices.51.Suggett