While the Particle Summit seems like only yesterday it’s already time to head for the US Pharmacopoeia workshop on particle size – or the ‘Workshop on Particle Size: Particle Detection and Measurement’ to give it its full title. So I’m off to Rockville, Maryland, home of the USP.
The program looks great with some very welcome industrial input from ‘big pharma’ in the shape of Pfizer, Eli Lilly, GSK and Boehringer Ingelheim. I’m particularly looking forward to the sessions led by industrialists about desirable formulation properties for different delivery strategies. And, of course, I’ll be extremely interested to see what all the experts present have to say about different particle sizing techniques used by the industry.
Why focus on particle size?
Particle size is frequently designated a critical parameter in the manufacture of pharmaceuticals, which is why it justifies a workshop all to itself! The different delivery strategies employed to introduce active ingredients into our bodies are increasingly sophisticated and well-controlled which is why I’m looking forward to these particular sessions. The particle size requirements for tablets, topical creams and inhalation are all so very different.
In tablet production, for example, particle size may be controlled to ease flow during manufacture and ensure content uniformity in the finished product. Once the tablet has been swallowed, the particle size of the active may also influence the rate at which it dissolves and therefore the drug’s bioavailability. By tailoring particle size and tablet structure to control the rate of dissolution it becomes possible to produce drugs with defined extended-release profiles.
Inhaled drug delivery is the other area that Malvern have some experience of since we’ve done a lot of work on nasal sprays and dry powder inhalers. Because we can measure the particle size of sprays in real-time as the droplets or powder particle leave the device we can study the dispersion mechanisms involved in considerable detail. As an example, researchers at Monash University have recently published some great new work showing how you can use particle size data to characterize the de-agglomeration profiles of different dry powder inhaler formulations, for better device and formulation development. You can meet these guys at DDL 21 in Edinburgh, Scotland which is running at the same time!
Developing new standards
Laser diffraction particle sizing is not mandatory for inhaled product testing but it is highlighted at various points in the USP. One of the aims of the workshop is to identify the data requirements for developing and revising USP particle size standards and as such it will be interesting to see what’s raised in this session.
Last but not least, I too will be presenting on the topics of ‘<429> issues’ and ‘Statistical Considerations Involving Particle Size Analysis’. I hope to stimulate some lively debate. Look out for next week’s blog post – the conference runs from December 8th to 10th.