Inhaled bronchodilators and anticholinergics are the mainstay in the management of patients with chronic obstructive pulmonary disease. This study compared the in vitro aerosol characteristics from an HFA ipratropium bromide pMDI (Atrovent, 20 μg ipratropium bromide, Boehringer Ingelheim Ltd) with two anti-static VHCs, a preproduction OptiChamber Diamond (Diamond; Philips Respironics) and an AeroChamber Plus Z-Stat (Z-Stat; Monaghan Medical Corp.) VHC, a conventional AeroChamber Plus (AC+, Monaghan Medical Corp.) VHC, and the pMDI alone. Six pMDIs were primed before use and six of each VHC were washed and air dried. For each run (n) the pMDI was actuated into the VHC or next generation impactor (NGI) (for pMDI alone - tested before and after VHC tests), followed by 20 s extraction at 30 L/min, repeated 10 times. Drug deposits from the NGI were analyzed using HPLC. The Emitted Dose (ED; drug entering the NGI), Fine Particle Dose (FPD; amount of drug ≤ 4.7 μm), Fine Particle Fraction (FPF;% of ED in particles ≤ 4.7 μm), and Mass Median Aerodynamic Diameter (MMAD) were determined using Copley Inhalation Testing Data Analysis Software (CITDAS). Table 1. Results: Mean (Standard Deviation) Device ED (μg) FPD (μg) FPF (%) MMAD (μm) pMDI alone (n=12) 16.5 (0.9) 5.7 (0.6) 34.6 (4.7) 0.87 (0.05) pMDI with Diamond VHC (n=6) 8.2 (0.6) 6.1 (0.9) 74.3 (6.7) 0.92 (0.04) pMDI with Z-Stat VHC (n=6) 8.6 (0.7) 6.3 (1.1) 73.0 (7.9) 0.87 (0.02) pMDI with AC+ VHC (n=6) 7.4 (1.0) 5.2 (0.9) 69.6 (3.9) 0.87 (0.02) The aerosol characteristics were similar between the VHCs and removed significant potential throat deposition compared to the pMDI alone.
Nikander et al. (2011) studied this question.