PURPOSE: VHCs are prescribed for patients that have difficulty coordinating pressurized metered-dose inhaler (pMDI) use. Conditioning in detergent solution mitigates the impact of electrostatic charge, but may not always be performed. Our study sought to evaluate if the use of charge dissipative compared with non-conducting materials in VHCs maintains aerosol delivery even when not pre-washed.
METHODS: AeroChamber Z-STAT Plus® (Z-STATPLUS) VHCs (Monaghan Medical Corp., Plattsburgh, NY), manufactured from charge dissipative materials were evaluated directly after removal from their packaging with 45 μg/actuation levalbuterol ex actuator mouthpiece (Xopenex®-HFA, Sepracor Inc., Marlborough, MA) as representative beta-2 agonist. OptiChamber® Advantage (OPTI) VHCs (Respironics Inc, Cedar Grove, NJ), representing non-conducting devices, were also similarly evaluated. Each VHC (n = 5/group) was tested using an Andersen 8-stage impactor with USP Induction Port operated at 28.3 L/min ± 5%, representative of flow rates seen with adult patients. A shutter that interfaced between the VHC mouthpiece and induction port was used to simulate 2-, 5- and 10-s delay intervals between pMDI actuation and the onset of sampling. The shutter allowed flow from the VHC to the impactor only after the defined delay. 5-actuations were delivered at 30-s intervals. The induction port and impactor stages were subsequently assayed for albuterol by HPLC-UV spectrophotometry. Benchmark measurements were made with the pMDI alone.
RESULTS: Fine particle mass/actuation (FPM), representing particles <4.7 μm aerodynamic diameter (mean (95% CI), was 39.5(2.8) μg for the pMDI alone. Values of FPM(Z-STATPLUS) were 31.7(2.0) no delay; 25.3(2.4) 2-s; 24.5(1.6) 5-s and 22.0(2.8) 10-s delay. Corresponding values of FPM(OPTI) were 18.8(1.4) no delay; 13.1(5.8) 2-s; 5.3(3.4) 5s and 3.6(3.4) 10-s delay.
CONCLUSION: Both non-electrostatic VHCs delivered significantly more medication than the non-conducting VHCs with or without delay.
CLINICAL IMPLICATIONS: Aside from other design considerations, the use of an unconditioned VHC manufactured from a non-conducting material may have an adverse clinical effect when used to deliver Xopenex®-HFA.
DISCLOSURE: Dominic Coppolo, Employee All authors are employees of Trudell Medical International or Monaghan Medical Corp., subsidiary companies of Trudell Medical Group Ltd.