The Science Journal of the American Association for Respiratory Care

2000 OPEN FORUM Abstracts

IN-VITRO COMPARISON OF THE PERFORMANCE OF VALVED HOLDING CHAMBERS FOR DELIVERY OF SEREVENT® INHALATION AEROSOL

Anne Leslie Stevens, BS, RRT, CPFT; Mark Holmes, BSc (Hons); Anna Furlong, BS; and, Colin Reisner, MD. GlaxoWellcome, Inc., Research Triangle Park, NC

Background: The dose of inhaled drugs delivered to the lung from a metered dose inhaler (MDI) depends on factors such as airway anatomy, disease state and inhalation pattern. Timing MDI actuation with inhalation is difficult and using a valved holding chamber (VHC) may decrease coordination issues. Yet, the respirable fraction, fine particle mass (FPM), of drug delivered from VHCs must be comparable to the FPM from the MDI. This study compares the delivered dose of Serevent via three brands of VHCs.
Method: The delivery of Serevent® (total unit dose 21mcg ex-actuator, GlaxoWellcome, Inc.) via Aerochamber® (Monaghan Medical Corp [AC]), Aerochamber Plus® (Monaghan Medical Corp [AC+]) and Optichamber? (Healthscan Products, Inc, [OPT]) was compared. The dose delivered from the VHCs was obtained using an Andersen cascade impactor. All VHCs were washed with detergent per package instructions. Three different Serevent® inhalers were evaluated with each VHC (n=3, AC and AC+; n=6, OPT). The VHC was attached to the throat of the impactor and sampling flow was established at approximately 28.3 l/min. The inhaler was shaken ³5 seconds and attached to the VHC, fully depressed for one second then left in place for 30 seconds. This process was repeated to deliver 10 doses to each VHC. The stages of the impactor and the VHC were assayed for Serevent® by HPLC. A Serevent® control was assessed with every analysis.
Results: The mean dose from stages 4, 5, and 6 (FPM) of the impactor for the Serevent® controls was 14.00 mcg. The table below compares the FPM of the VHCs to the control:

VHC mean FPM* (mcg) Difference VHC vs Serevent® S.E. 95% Confidence Interval
Lower Upper
AC 13.67 -0.33 0.30 -0.97 0.31
AC+ 15.01 1.01 0.33 0.29 1.73
OPT 14.01 0.01 0.38 -0.77 0.79
*particles 0.7-3.3 mm in diameter

Conclusions: These in-vitro data demonstrate that:
? FPM is clinically comparable across VHCs and to the original product; and,
? the tested VHCs are reasonable for administration of salmeterol.

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