Spray Characterisation at Rechon QC laboratory

This is a re-run from November 2011 and January 2013 and it is one of our most appreciated and widely read blogs. Ronny Hansson, one of Rechons many skilled analysts, enlightens us about the instrumentation and techniques for Spray Characterisation of oral and nasal sprays.
Rechon has extensive experience of spray characterisation and the instrumentation can perform characterisations on both nasal and oral sprays.
Spray characterisation is increasingly used in the pharmaceutical industry for bioavailability studies and as a substitute or supplement to bioequivalence studies. Rechon performs Spray Characterisation studies for several of our customers’ products and our in-house projects.
A normal Spray Characterisation Study consists of six parts:
1. Spray Weight Uniformity
2. Droplet Size Distribution
3. Spray Pattern
4. Spray Angle
5. Priming and Repriming
6. Tail Off
Spray Weight Uniformity ensures that every spray bottle delivers the label clamed amount of the drug product from multiple sprays from the beginning to the end of a spray bottle.
Figure 1: Weight station for Spray Weight Uniformity, Priming/Repriming and Tail Off.
Droplet size distribution is another characteristic which should be thoroughly controlled. It is crucial to limit the size distribution to get a satisfactory bioavailability. Spray bottles usually produced spray droplets between 20 to 120 µm.
Smaller particles can deposit in the lungs and cause complications.
Figure 2: Droplet Size Distribution at the stable spray phase.
Figure 3: Laser diffracter for Droplet Size Distribution
Spray Pattern and Spray Angle provide valuable information about the plume shape and density. Different shapes and densities are obtained by different spray nozzles and pump volumes. To be able to measure these characteristics the test is performed with a high speed camera of at least 500 frames/s.
Figure 4: Optical spray analyser for Spray Pattern and Spray Angle
Priming and Repriming studies are conducted to determine how the spray bottle should be primed to get a satisfactory Spray Weight and thus deliver the label clamed amount of drug product. The testing includes different spray bottle orientations and different periods of non use.
Tail Off profile is conducted after the last labelled number of actuations. Tail Off includes at least Spray Weight and Droplet Size Distribution of sprays to the end of spray bottle exhaustion.
Rechon has the following three sets of instruments for Spray Characterisation Studies:
• Malvern Spraytec laser diffracter for measurement of Droplet Size Distribution
• Innova Systems weight station for measurement of Spray Weight Uniformity, Priming/Repriming and Tail Off
• Innova Systems optical spray analyser for measurement of Spray Pattern and Spray Angle
For more information regarding what Rechon can do for your business, please contact us on business@rechon.se.