FAQ - Pharmaceutical/Life Sciences Particle Counting

Question
Do you have any new information on foreign particle detection and limits for dry powder inhalers. I am current on the FDA's lack of momentum but looking to see if you could offer an insight on global work in this area or domestic work that I may not have seen.

Answer

Yes, unfortunately the extent of the FDA in helping assign limits is still 21 CFR 820 where a Quality Procedure should define the product/process. This is less than useful.

I have been involved in some studies looking at sterile closure cleanliness and in particular following the USP <381> test. This requires a cleanliness function that uses turbidity as the means to measure, however once on gets as far as turbidity you are not dealing with individual particles but a cloud of particles. Testing must therefore remain the same as we discussed last year, i.e. test sufficient of your own products to verify that an acceptable baseline exists (USP<1086> allows for certain impurities to exists providing they do not have an undesirable biological reaction) and then use this 95% confidence level as your limit for release.

Malvern Instruments (a sister company to Particle Measuring Systems, part of the Specris PLC Group) has a product called Spraytec that has particle size analysis for inhalants. If the testing above proves that residual particles of a certain size are present then this product would determine its function on overall particle distribution of finished, filled, delivered product.

That is the limit of business to date, unfortunately the emphasis is still on you the manufacturer to prove it is safe rather than have legislation drive the process.

Contact us if you need more information or have questions.