Class of 2012 Abstract / Specific Aims: To evaluate the in vitro throat deposition and respirable mass of the QVAR® pressurized metered-dose inhaler (pMDI) alone or coupled to an accessory device, such as the AeroChamber Valved Holding ChamberTM or various nonconventional accessory devices. Methods: The performance of the AeroChamber and nonconventional accessory devices, including a toilet paper roll, paper towel roll, rolled paper, plastic bottle spacer, plastic bottle reverse-flow holding chamber, and nebulizer reservoir tubing, were compared to no accessory device. Throat deposition and respirable mass were evaluated using a United States Pharmacopeia (USP) inlet ("throat") coupled to instrumentation for particle size analysis. Each configuration was tested with three actuations and repeated in quadruplicate. The amount of drug deposition was quantified using high-performance liquid chromatography. The data were analyzed using multiple independent t-tests assuming unequal variances. An a priori α-threshold of 0.05 was used with a Bonferroni corrected α of 0.007. Main Results: Compared to the pMDI alone, all of the accessory devices had significantly lower throat deposition (p < 0.001) and significantly higher respirable fraction (p < 0.001). Differences in respirable mass were not significant for any accessory device (p ≥ 0.049), except the paper towel roll and the nebulizer reservoir tubing (p < 0.001). Conclusions: Under these testing circumstances, nonconventional accessory devices, such as the toilet paper roll, rolled paper, plastic bottle spacer, and plastic bottle reverse-flow holding chamber, effectively reduce throat deposition and maintain respirable mass compared to a QVAR pMDI alone. Therefore, they may be suitable alternatives to commercial spacers.

Class of 2012 Abstract / Specific Aims: To evaluate the in vitro throat deposition and respirable mass of the QVAR® pressurized metered-dose inhaler (pMDI) alone or coupled to an accessory device, such as the AeroChamber Valved Holding ChamberTM or various nonconventional accessory devices. Methods: The performance of the AeroChamber and nonconventional accessory devices, including a toilet paper roll, paper towel roll, rolled paper, plastic bottle spacer, plastic bottle reverse-flow holding chamber, and nebulizer reservoir tubing, were compared to no accessory device. Throat deposition and respirable mass were evaluated using a United States Pharmacopeia (USP) inlet ("throat") coupled to instrumentation for particle size analysis. Each configuration was tested with three actuations and repeated in quadruplicate. The amount of drug deposition was quantified using high-performance liquid chromatography. The data were analyzed using multiple independent t-tests assuming unequal variances. An a priori α-threshold of 0.05 was used with a Bonferroni corrected α of 0.007. Main Results: Compared to the pMDI alone, all of the accessory devices had significantly lower throat deposition (p < 0.001) and significantly higher respirable fraction (p < 0.001). Differences in respirable mass were not significant for any accessory device (p ≥ 0.049), except the paper towel roll and the nebulizer reservoir tubing (p < 0.001). Conclusions: Under these testing circumstances, nonconventional accessory devices, such as the toilet paper roll, rolled paper, plastic bottle spacer, and plastic bottle reverse-flow holding chamber, effectively reduce throat deposition and maintain respirable mass compared to a QVAR pMDI alone. Therefore, they may be suitable alternatives to commercial spacers.

Class of 2015 Abstract / Objectives: To evaluate the in vitro performance of various pressurized metered dose inhaler (pMDI) formulations by cascade impaction primarily focusing on throat deposition, fine particle fraction (FPF), and mass-median aerodynamic diameter (MMADR) measurements Methods: Ten solution pMDIs were prepared with varying cosolvent species in either low (8% w/w) or high (20% w/w) concentration. The chosen cosolvents were either alcohol (ethanol, n-propanol) or acetate (methyl-, ethyl-, and butyl acetate) in chemical nature. All formulations used HFA-134a propellant and 0.3% drug. The pMDIs were tested by cascade impaction with three different inlets to determine the aerodynamic particle size distribution (APSD), throat deposition, and FPF of each formulation. Theoretical droplet evaporation time (DET), a measure of volatility, for each formulation was calculated using the MMADR. Results: Highly volatile formulations with short DET showed consistently lower throat deposition and higher FPF than their lower volatility counterparts when using volume-constrained inlets. However, FPF values were not significantly different for pMDI testing with a non-constrained inlet. The MMADR values generated with volume-constrained inlets did not show any discernible trends, but MMADR values from the non-constrained inlet correlated with DET. Conclusions: Formulations with shorter DET exhibit lower throat deposition and higher FPF, indicating potentially better inhalational performance over formulations with longer DET. There appear to be predictable trends relating both throat deposition and FPF to DET. The shift in MMADR values for volume-constrained inlets suggests that large diameter drug particles are preferentially collected in these inlets.