Inas® — Medical Aerosol Spectrometer

Inas® — time resolved particle size and particle quantity determination of spray bursts, nebulizers and pharmaceutical inhalers at highest concentrations


Inas® is the only measuring device worldwide which can determine particle sizes and particle quantities in concentrations up to 107 particles/cm3 by means of a countable measuring procedure and additionally offers a temporal resolution by which the transient processes can be resolved in milliseconds.

Inas® is an optical light-scattering spectrometer with integrated dilution unit for the temporally resolved characterization of spray bursts and aerosols. It can be operated with variable suction volume flowrates up to 100 l/min.

The Inas® measurement technology uses a high-capacity digital processor which makes it possible to investigate the dispersion and delivery process over time, looking at concentration and other statistical distribution parameters, e.g. the Sauter diameter, at sampling intervals of around 10 milliseconds.

Inas® is therefore very capable in the characterization of spray bursts, nebulizers and pharmaceutical inhalers like MDIs (Meter Dose Inhalers) or DPIs (Dry Powder Inhalers) in the diameter range of 0.2 – 40 µm.

With Inas®, the duration of a spray burst measurement including the completed data evaluation is being reduced on the duration of the spray burst.

The Inas® system has been developed in co-operation with the Pharmaceutical Institute at the Christian-Albrechts-University in Kiel/Germany, under the direction of Prof. Dr. Hartwig Steckel.

The performance of the system in comparison with a conventional mass based measurement device, the Next Generation Pharmaceutical Impactor or NGI, has been assessed in scientific studies and found to give good correlation. Results are documented in Maren Kuhli's dissertation "Entwicklung von Aufgabesystemen zur Charakterisierung pharmazeutischer Aerosole mit einem optischen Partikelzähler" [ Development of methods for the characterization of pharmaceutical aerosols with an optical particle counter] from the Faculty of Mathematics and Natural Sciences of the Christian-Albrechts-University in Kiel.

In constrast to an impactor based method, the results of an analysis are produced in seconds and can be resolved for the complete burst giving the opportunity to identify time based characteristics in the aerosol generation process.

The optical measurement technology of Inas® is based on the measurement technology of the welas® digital system with best particle size resolution and size classification accuracy. The evaluation of the measured data for the determination of particle size distributions is exclusively based on unambigeous, mathematically reproducible processes unlike some other particle measurement systems.

Technical parameters

  • Measurement range: 0.2 - 40 µm
    • Cn ≤ 107 Particles/cm3
  • Temporal resolution up to 10 milliseconds
  • Volume flow adjustment according to the European pharmacopeia:
    • 15 l/min (nebulizers)
    • 30 l/min (MDI)
    • variable flow rate with differential pressure of 4 kPa (DPI)
    • adjustable up to 100 l/min
  • Power supply: 115/230 V ; 50/60 Hz

Application examples

  • Characterization of nozzles for sprays and nebulizers
  • Characterization of inhalational aerosols according to European pharmacopeia with 15 l/min (nebulizer), 30 l/min (MDI) or variable flow rate with differential pressure of 4 kPa (DPI)
  • Production control of spray and nebulizer systems

Particular advantages

  • Largest measurement range 0.2 – 40 µm (3 measurement ranges in one device)
  • Very high temporally resolved particle size and particle quantity determination with up to 10 ms
  • Largest concentration range up to 107 Particles/cm3
  • Characterization of a single spray burst in a few seconds
  • Fast determination of size distributions and concentrations
  • Calibration, cleaning and lamp exchange can be accomplished by the user
  • Comprehensive, practice-oriented, user-friendly software
  • Low maintenance
  • Easy handling
  • Reliable operation

Please contact us for more detailed information.