2004 OPEN FORUM Abstracts
IMPROVED PERFORMANCE FROM A VALVED HOLDING CHAMBER (VHC) WITH BODY MANUFACTURED FROM A TRANSPARENT, BUT ELECTROSTATIC CHARGE DISSIPATIVE POLYMER
Jolyon
P. Mitchell Ph.D, Kimberly J. Wiersema B.A., Cathy C. Doyle B.Sc,
and
Mark W. Nagel HB.Sc Trudell Medical Aerosol Laboratory, London,
Canada
Particle deposition
caused by electrostatic attraction to the walls of VHCs made from
non-conducting polymer can significantly reduce pressurized metered
dose inhaler (pMDI) medication delivery, especially at first use (1).
This study explored the potential for improved performance with a
new VHC with body manufactured from a transparent custom charge
dissipative polymer (AeroChamber Max™, Monaghan Medical Corp.,
Plattsburgh, NY), compared with a conventional transparent, but
non-conducting VHC (ProChamber™, Respironics Inc., Cedar Grove,
NJ). Before testing, both groups of devices (n=3/group) were
pre-washed in ionic detergent following each manufacturer’s
instructions. Fine particle mass/actuation (FPM), based on
particles < 4.7 µm aerodynamic
diameter, was determined by Andersen 8-stage cascade impactor at 28.3
L/min ± 5% in accordance with <601> of the US
Pharmacopeia. A 2-s delay was introduced between pMDI actuation and
sampling via the impactor to simulate use by poorly coordinated
patients. 15-actuations of Combivent® (Boehringer-Ingelheim
(Canada) Ltd., Mississauga, ON (18 µg
ipratropium bromide (IPR) + 90 µg
albuterol base equivalent (ALB)) were delivered at 30-s intervals
from a pre-primed canister. This formulation carried a significant
electrostatic charge (+170 ± 80 pC (mean ± SD)), based
on 5 separate actuations from a single pMDI into a Faraday cup
electrometer. Values of FPM (mean ± SD) are summarized in
the Table
| VHC type | FPM (µg) | Mass Retained by VHC (µg) | ||
| ALB | IPR | ALB | IPR | |
| AeroChamber Max™ | 41.4 ± 1.7 | 8.9 ± 0.5 | 15.5 ± 2.9 | 4.1 ± 0.3 |
| ProChamber™ | 18.1 ± 4.0 | 3.6 ± 0.8 | 37.8 ± 3.9 | 9.5 ± 0.9 |
FPM from the AeroChamber
Max™ VHCs was significantly greater than that from the
ProChamber™ VHCs (un-paired t-test, p < 0.001), and was
associated with decreased retention of both ALB and IPR by the VHC by
the former chamber (p ≤ 0.001).
The use of charge dissipative materials is more effective than
pre-washing a non-conducting device for the delivery of this
formulation, and is likely to lead to a better therapeutic outcome
for the uncoordinated patient prescribed a VHC.
(1) Piérart, F.,
Wildhaber, J.H., Vrancken, I. et al., Eur. Respir J.
1999;13:673-678.