Related Experiment Video
Updated: Aug 6, 2026
08:14
Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction
Published on: September 16, 2016
Correlation between inertial impaction and laser diffraction sizing data for aerosolized carrier-based dry powder
Xian-Ming Zeng1, Helen B MacRitchie, Christopher Marriott
1King's College London, Pharmaceutical Science Research Division, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK.
Pharmaceutical Research
|August 11, 2006
Summary
Laser diffraction accurately measures fine particle fraction (FPF) in dry powder aerosols, correlating well with inertial impaction. This allows for efficient quality control of aerosol formulations.
Area of Science:
- Pharmaceutical Technology
- Drug Delivery Systems
- Particle Engineering
Background:
- Accurate characterization of fine particle fraction (FPF) is crucial for dry powder inhaler (DPI) efficacy.
- Traditional methods like inertial impaction can be time-consuming.
- Laser diffraction offers a potentially faster alternative for FPF assessment.
Purpose of the Study:
- To evaluate the correlation between FPF measured by laser diffraction and inertial impaction for various DPI formulations.
- To determine the suitability of laser diffraction for quality control of DPIs across different flow rates.
Main Methods:
- Prepared 16 dry powder formulations (binary and ternary) with salbutamol and different sugars/lactose.
- Measured FPF (< 5 microm) using laser diffraction and inertial impaction at flow rates from 28.3 to 100 L/min.
- Analyzed correlation between the two measurement techniques.
Main Results:
- Laser diffraction, considering particles < 60 microm, accurately determined FPF (< 5 microm).
- A strong linear correlation (r2 = 0.934) was observed between laser diffraction and inertial impaction measurements.
- Correlation was consistent even with the addition of fine lactose particles.
Conclusions:
- Laser diffraction effectively reflects the aerodynamic properties of drug particles in DPIs.
- Laser diffraction is a viable technique for on-, in-, and at-line quality control of dry powder aerosol formulations.
- This method can streamline the quality control process for inhaled medications.
