Laser diffraction analysis of pharmaceutical metered dose inhalers, pump sprays and pressurised sprays with droplets or solid particles from 0.25 µm to 875 µm
Together with the flexible SPRAYER adapter, the compact laser diffraction sensor HELOS/BR offers meaningful and reproducible analysis of the size distribution of droplets or solid particles in pump sprays, metered dose inhalers (MDI) and other pressurised sprays in the range from 0.25 µm to 875 µm. The adapter can be flexibly adapted for a wide range of different atomizer types and simulates the manual application of the relevant spray with a force or trajectory actuator.
The formation of a spray mist depends on many different parameters, and these need to be taken into account and controlled when setting up reproducible measuring conditions. Important triggering parameters include e.g. the force and acceleration conditions when the atomizer is used. Likewise, the distance and orientation of the spray in relation to the measuring zone also have an influence on the measurement results. A suction unit ensures that laminar flow conditions are established in the measuring zone and that the spray mist is purged out. In the HELOS & SPRAYER system, the key measurement and triggering parameters and the distance between the spray nozzle and the measuring zone can be controlled with the software and saved as retrievable measuring methods (Standard Operating Procedures (SOPs)). Alternatively, the integrated control panel allows for a direct and manual control of the system.
Two actuators are optionally available for the SPRAYER for simulation of different triggering processes. The force actuator ensures that the spray is actuated with a definable, constant force by pushing the actuator piston onto the triggering mechanism. On the trajectory actuator, the atomizer can be triggered with a motion path for the actuator piston that is defined by the travel (stroke), acceleration and speed. The use of controlled triggering processes that are executed by means of the actuators helps to establish reproducible measuring methods and avoids unwanted operator bias.
For reliable identification of the different spray phases (formation, stable phase, dissipation), a time-resolved measurement of the generated spray mist is performed with up to 2,000 particle size distributions per second. The identification of the stable phase of spray formation forms the basis for the reproducibility of subsequent measurements in the fully developed droplet cloud. The force or acceleration, speed and stroke of the triggering process are recorded by the software and can be displayed in different diagrams.
The system creates the best conditions for compliance with the requirements of regulatory authorities for pharmaceutical products, e.g. the guidelines of the US FDA (Food and Drug Administration). HELOS & SPRAYER are used accordingly both for fundamental research applications and in product development, as well as in quality control.
In order to simulate the way a nasal spray is tilted in the actual application by the user, this system can be upgraded with the traversing unit ROTOR. In addition, the modular concept of the HELOS laser diffraction series allows this configuration to be systematically expanded with numerous dispersion units and dosing options to open up many more measuring applications.
- Particle and droplet size distribution | FDA-compliant
- For metered dose inhalers, pump sprays and pressurised sprays
- For research, product development, quality control
- 4 high-resolution measuring ranges from 0.25 µm to 875 µm | R2 to R5T
- Time-resolved measurements for identification of the spray phases
- Software-controlled adjustment of the spray position
- Fully-automatic spray triggering with predefined force or speed
- Recording of force, stroke, acceleration, speed