Laser particle sizing ensures accuracy of new nasal inhalers

Published: 2-May-2008

Performance testing for nasal delivery devices is one of the new services being offered by UK company Melbourn Scientific.

Performance testing for nasal delivery devices is one of the new services being offered by UK company Melbourn Scientific.

The potential of a nasal route for a wide range of treatments from the instant relief of panic attacks through to needle-free vaccinations creates new challenges for devices and requires new testing regimes.

Melbourn Scientific uses a range of techniques to determine particle size and behaviour and can provide advice on the comparative benefits of the different techniques. It can also offer method development and validation. In particular, it is the first UK contract laboratory to offer GLP and GMP compliant laser particle sizing for nasal sprays using the Malvern Spraytec.

The Spraytec system allows for the complete characterisation of the aerosol produced by nasal spray devices by measuring droplet size distributions using laser diffraction. The spray is passed through a laser beam and the angular intensity of the scattered light is measured. This scattering pattern is then analysed using an appropriate optical model to yield a size distribution.

Laser screening provides a measurement of the size and distribution of the particles but does not identify them. However, the speed, accuracy and consistency of laser particle analysis is making this technique popular, especially in the development of new devices.

"The challenge of a nasal delivery device is to get the particle size right in order to ensure that drug is deposited within the nasal passages and not the lungs or gastro-intestinal tract," said Mark Hammond, business development director of Melbourn Scientific. "Research has shown that a particle size of greater than 10 to 20µm is required to optimise this."

Melbourn Scientific has been involved in a number of device developments for companies taking a lead in this field. For nasal devices the company is able to offer a portfolio of tests to characterise and measure particles and their distribution.

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