Corresponding author: Nattika Nimmano (
The properties of aerosols generated from salbutamol sulfate solution (1 mg/mL) using an air-jet nebulizer were evaluated using Next Generation Impactor (
Aerodynamic Particle Size Distribution (
The gold standard for measuring the
The Next Generation Impactor (
Abbreviated impactor measurements (AIMs) have recently been developed to speed up the process (
Nebulizers are categorized into three main types: air-jet, ultrasonic and vibrating-mesh. The air jet nebulizer is the most common inhaler device. It is connected to an air compressor using a tubing. Air is compressed causing the air to flow at high velocity through the liquid formulation, thereby turning it into an aerosol suitable for inhalation.
The proposed approach using
Salbutamol sulfate was sourced from Micro Technologies, UK. Acetronitrile (99.9%, gradient grade for
A PARI LC® Sprint Reusable Nebulizer (PARI Medical Ltd, Byfleet, UK) was used to deliver aerosol of salbutamol sulfate. The aerosol properties of salbutamol sulfate were characterized with
Various volumes of
Salbutamol sulfate was assayed at 276 nm using an
The
After 9-min nebulization, salbutamol sulfate were collected from the nebulizer reservoir, mouthpiece, mouthpiece adaptor, induction port, collecting cups and the back-up filter using
Fine Particle Dose (
Fine Particle Fraction (
Mass Median Aerodynamic Diameter (
Geometric Standard Deviation (
A two-stage abbreviated impactor,
The
Analysis of aerosolization parameters i.e., Emitted Dose (
Fine Particle Dose (
Fine Particle Dose (
Statistical analysis of all measurements was carried out using IBM SPSS Statistic 22 Software. The results are presented as mean ± standard deviation (SD). Comparison between the two groups was done using Student’s
Longer times for aerosolization to dryness were required with increase in fill volumes of water from 2 to 8 mL in the air-jet nebulizer. Nebulization periods between 5 and 10 min are recommended, and an extended nebulization time may reduce patient adherence (
In this study, it was observed that 2 mL was the least fill volume for this specific device. However, approximately 55% was released as aerosol. Increasing fill volume from 2 to 8 mL significantly increased the percentage of aerosolization from 55 to 87%, respectively. Time taken to dryness between fill volumes of 4 and 8 mL of
Effect of fill volumes of water on (A) dryness time and (B) percentage of nebulized (n=3, mean± S.D.).
Fig.
Mass of salbutamol sulfate deposited at each stage of (A) the
For
The values of % mass balance for all runs were within the European Pharmacopoeia acceptance limit of 75–125% (
Aerosol parameters of salbutamol sulfate nebulized into the impactors at the flow rate of 15L/min (n=3, mean± S.D.).
Aerosolization parameters |
|
|
---|---|---|
71.56± 1.35 | 69.54± 4.58 | |
1.97±0.11 | 0.94±0.18 | |
68.6±2.5 | 43.0±1.2 | |
|
5.02±0.35 | – |
|
2.12±0.03 | – |
There was no significant difference in emitted dose (
Structure of (A) the
The different
The lower values of
Few studies have demonstrated equivalent values of
Other future research could evaluate the effect of changes in formulation i.e. change in viscosity or surface tension of nebulizer liquid, in the discriminatory ability of the cascade impactor methods due to the limitation of current results. The study could also test for level of variations from multiple operators to check for sensitivity of both impactors.
The
The authors would like to give a special thanks to Ms Satinder Sembi (UCL) for her expertise with the