Malvern targets particle size analysis of inhalers

Analytical instrumentation supplier Malvern has introduced a new inhalation cell for its Spraytec system for particle size analysis of aerosols and sprays, allowing the rapid characterisation of systems such as dry powder inhalers (DPIs), metered dose inhalers (MDIs) and nebulisers.

Particle size in sprays and aerosols is important in defining product delivery and performance in an increasing range of pharmaceutical applications.

The new cell makes Spraytec's laser diffraction technology available to inhaler developers, delivering real-time, high-speed particle size measurements for the complete characterisation of continuous and pulsed spray events.

Measurements can then be carried out under fixed or varying flow rate conditions, so the system is ideal for the optimization of active pharmaceutical ingredient (API) delivery by the inhalation route.

With a data acquisition rate of 10 kHz - in practice a 100-microsecond time resolution - it offers accurate analysis of the dynamics of spray atomisation and dispersion, so that even the rapid changes in particle size that take place during inhaler operation can be monitored.

What is more, Spraytec can measure particle size distributions over an extremely broad dynamic range (0.1 - 2000 microns), using just two lens systems and avoiding endless lens changes.

"We released a new inhalation cell because we wanted to make it more accessible, easier to break down and clean, and also compatible with our new Spraytec model we released in September," Paul Kippax, the company's product manager for laser diffraction products, told In-PharmaTechnologist.com.

"It is important that when patients get hold of inhalers that the product is delivered effectively, so with dry powders for example, which have a very fine particle size, our system makes it easier to assess if the patient's inhalation energy is enough to disperse it."

If required, the inhalation cell can be used in-line with conventional impaction techniques and is fully compatible with the associated flow control systems, allowing correlation with traditional methods, Malvern said.

However, as opposed to conventional techniques which offer six measurements a day, this system offers several hundreds, enabling the rapid screening of formulations for correct dispersion performance.

In addition, it also provides greater insight into particle formation and dispersion, and, since laser diffraction measurements are independent of flow rate, the Spraytec with the inhalation cell allows the measurement of particle size distributions during the operation of a device using model patient profiles, thus providing a more-realistic mimic of real-life performance.

Malvern says the Spraytec system is exceptionally easy to use, with built-in SOP wizard aiding method definition and transferability and offering single-click operation.

Full lifecycle documentation, following GAMP guidelines, provides complete design traceability; IQ/OQ documentation is provided for validation plans; and software provides technical compliance with the requirements of 21 CFR Part 11.