Delivered Dose Comparison between Breath-activated and Breath-enhanced Nebulizers

S Byrne, R H M Hatley

Different types of nebulizer are designed to have different drug delivery efficiencies, which may interact with a range of user-specific factors, such as drug formulation and breathing pattern, to affect the delivered dose. We tested 2 different types of jet nebulizer, using 2 different drugs and an adult breathing pattern, to determine the difference in aerosol delivery over time. A breath-enhanced nebulizer (LCS; LC Sprint, PARI GmbH) and a breath-activated nebulizer (AEII; AeroEclipse II, Monaghan Medical Corp.) were connected, via a filter, to a breathing simulator set to generate an adult breathing pattern (BP; tidal volume = 600 mL, inhalation:exhalation
ratio = 1:2, 10 breaths per minute). Each nebulizer was loaded with salbutamol sulphate (2.5 mg/2.5mL, Salamol Steri-Neb, IVAX Pharmaceuticals) and run with the BP for 20 minutes using 6 L/min from a medical air supply. The filter was changed every minute until 20 filters had been collected, and the commencement of sputter was noted. Aerosol deposited on the filter was analyzed using high performance liquid chromatography. The tests were repeated using budesonide inhalation suspension (BIS; 0.25 mg/2 mL, Pulmicort, AstraZeneca). Average
fine particle fraction (FPF; % of particles <4.7 μm) for each drug was measured using a Malvern Spraytec laser particle sizer (Malvern Instruments Ltd). Respirable delivered dose (RDD) mass of particles <4.7 μm) was calculated. Nebulization time was much longer for the AeroEclipse II nebulizer than the LC Sprint, with mean sputter points of 711 and 261 seconds respectively using salbutamol sulphate, and 521 and 285 seconds respectively using BIS. RDD was also much higher for the AeroEclipse II than the LC Sprint nebulizer, with measures of 818 and 480 μg respectively using salbutamol sulphate, and 60 and 30 μg respectively using BIS. A small sample size was used for this study, so further testing is required to substantiate these preliminary findings.
Comparative testing of different types of nebulizer with child and adult breathing patterns and different drug formulations may provide useful information to inform prescribing decisions.

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