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In Vitro Comparison of Particle Size Distribution/Respirable Dose for LiteAire Spacer versus Misty Max –
10 Nebulizer Using Albuterol.
Sunil Dhuper MD, Sanjay Arora MD, Aziz Ahmed MD, Alpana Chandra MD ,Cynthia Chong MD, Chang Shim MD, Hillel W. Cohen DrPH, Scott Foss, Sonia Choksi MD
North Central Bronx Hospital, 3424 Kossuth Avenue, Bronx, New York 10467
An Affiliate of The Albert Einstein College of Medicine
Introduction
Despite tremendous variability in the number of MDI actuations (2-12) used in studies comparing beta agonist delivery via MDI/spacer and one unit dose ampule with a nebulizer, there is increasing literature support based on clinical trials for the use of 6 MDI actuations. As delivery systems influence the inhaled dose, it would be prudent to determine the in vitro dose outputs using the two systems prior to conducting a clinical efficacy comparison study between MDI/Spacer and nebulizer. In a prior in-vitro study, we have demonstrated no significant difference in the β-agonist total dose output between 6 actuations of MDI with LiteAire Spacer versus 1 unit dose ampule with a nebulizer. However, as particle size distribution was investigated with the two delivery systems, respirable dose output equivalency between the two systems remains undetermined. Therefore, the objective of this study is to compare the emitted dose particle size distribution and effective respirable dose between 6 actuations of albuterol MDI with LiteAire Spacer versus 1 unit dose ampule of a nebulizer. Discussion
This study demonstrates that using the breath simulation technique there is no significant difference in the total dose output using 6 actuation of albuterol MDI spacer versus 1 unit dose To determine the total dose output, a test device was attached to a USP of nebulizer albuterol. Even though the difference in the respirable fraction between the two throat model feeding into a filter connected to a Michigan Instrument Dual modes of delivery using ACI was significant, there was no difference in the total dose output Test Lung System. The lung was driven by a Puritan Bennet 7200 Ventilator in the effective respirable dose calculated using the breath simulation studies. We also set at 14 breaths/minute, tidal volume (TV) of 600 ml and inspiratory to determined that the total dose deposition using ACI with the two modes of delivery was not expiratory (I:E) ratio of 1:4. With LiteAire, an albuterol MDI (CFC Inhalation significantly different and well in line with the method using the breath simulated techniques. Aerosol – IVAX Pharmaceuticals, Inc.) was actuated at the beginning of The total dose output was found to be 175.9±27.0 µg for 6 We used Oxygen at a flow rate of 8 LPM for nebulizing albuterol, a standard practice for inhalation for 6 respiratory cycles (n=6 actuations) and with the nebulizer actuations of albuterol delivered to a LiteAire Spacer via MDI acute asthma in the emergency department. We determined that the impact of using oxygen (Misty Max 10), one 3-ml vial (0.833mg/ml) of albuterol solution was delivered versus 219.8±13.6 µg for a Misty Max 10 with T-piece. The instead of room air on the cut off diameter in the ACI is negligible. The cut off diameters for the over five minutes. O2 to the Nebulizer was set at a pressure of 50-Psi and a percent respirable fraction (defined as the total mass on plates # 3- ACI are dependant on the viscosities of gas used with the impactor. The viscosity of air is flow of 8 LPM. Each filter was washed with 0.05mM KCl with 1 % acetic acid 7 indicating a size range of 4.7-0.4 μm) was found to be 0.018centiPoise while that of 100% oxygen is 0.020centiPoise. The concentration of oxygen buffer to collect the deposited drug. Dosage was determined using a UV 90.26±1.51% for LiteAire and 81.68±0.66% for the Misty Max 10 and the respective viscosity when delivered at 8 LPM, with ACI operating at 28.3LPM flow was spectrophotometer, at a wavelength of 276 nm. Both devices were tested 3 (p<0.001). The particle size distributions are shown in Figure 3. 43% and 0.019centiPoise, respectively. Hence, the difference in viscosities of the two gases Table 1 summarizes the ACI results. The MMAD was 2.05±0.03 for used for the two modes of delivery (MDI /Spacer vs. Nebulizer) would be 0.001centiPoise. The Particle size was determined using an Andersen 8-Stage Cascade Impactor the LiteAire versus 1.49 ± 0.05 for the Misty Max 10 (p<0.0001) and impact of this difference on the cutoff diameters of ACI and therefore the respiratory particle (ACI) with USP throat. The ACI was operated at 28.3 LPM. A filter for the GSD was 1.64±0.03 for the LiteAire versus 2.25±0.06 for the collection of particle was placed after the last plate of the ACI instead of a Misty Max 10 (p<0.001). The effective respirable dose (total dose The optimal time for nebulization has been reported in the literature. In a study by Malone terminal filter inside the impactor. A TSI flow meter was connected between output from the breath simulation studies * respirable fraction in et al, it was determined that aerosolization past the sputtering point did not increase albuterol the ACI and vacuum pump. For the spacer unit (Figure 1), the vacuum pump micrograms) was 158.79+24.38 micrograms with the LiteAire vs. delivery. The study observed an abrupt decline in aerosol output that always corresponded to was turned on for at least 60 seconds. Six doses of medication were 179.57+11.11 micrograms for the Misty Max 10 ( p=0.27) the nebulizer sputtering with no change in the albuterol output between 30 to 60 seconds after dispensed at the rate of one actuation of albuterol MDI every the sputtering time for three different volumes (1.5 ml, 2.5 ml, and 3.5 ml albuterol solutions). ten seconds. For the T-nebulizer, setup using the Misty Max 10 (Figure 2), We chose 5 minutes nebulization time in our study as this was one minute past the sputtering the vacuum pump was turned on for at least 60 seconds and one 3-ml vial (0.833mg/ml) albuterol solution was delivered over five minute period using O2 at 8 L/min to the nebulizer. Each plate and the filter were washed separately with 10ml of 0.05 mM KCl with 1% acetic acid solution to obtain 9 Conclusion
samples. The 9 samples underwent analysis to quantify the dose of albuterolusing a UV spectrophotometer (λ=276 nm). The above experiment was When conducting a clinical efficacy study comparing MDI/Spacer and one unit dose of repeated for a total of three times (N=3), for both devices. albuterol delivered via nebulization, we recommend using 6 albuterol MDI actuations with spacer as the in vitro dose outputs with the two modes are comparable.

Source: http://www.nichemedical.com.au/pdf/comparison_of_particle_size_distribution_and_respirable_dose_for_liteaire_spacer_versus_nebuliser_poster_ats_2008.pdf