Laser diffraction-based particle size analyser used by Nektar Therapeutics to test dry powder inhaler formulations
Researchers at Nektar Therapeutics in the UK have used a Malvern Instruments laser diffraction-based Spraytec particle size analyser to test dry powder inhaler (DPI) formulations.
They have shown that drug particles produced using Nektar's supercritical fluid (SCF) crystallisation process disperse more effectively than micronised particles.
This opens the way for improved dose uniformity and better targeting of the correct deposition site of the drug within the respiratory tract.
The work has also shown that laser diffraction is a valuable tool in the rapid prototyping of new formulations in the pharmaceuticals industry.
Nektar is a drug delivery company with headquarters in the USA whose portfolio of technologies is used to develop improved drug products.
The Spraytec system was used in combination with cascade impaction, the pharmaceutical industry's traditional method for particle size analysis in aerosols.
Cascade impaction gives information about particle size, but not about the dynamics of aerosol formation.
Combining the two techniques gives valuable additional data, for example on how the excipient and drug particles interact during inhalation. Mahboob Rehman, research scientist at Nektar Therapeutics, said: "It took us just one day to get the results for this research using the Malvern Spraytec, allowing us to rapidly screen several prototype formulations." Those formulations that showed good dispersion were then selected for further characterisation.
Malvern's Spraytec uses laser diffraction to rapidly measure particle size.
This technique uses the principle that particles of different sizes will scatter light from a laser beam at an angle that is inversely proportional to their size.
It allows the dynamics of each actuation of an inhaler to be followed, with much faster result reporting and manipulation when compared with the industry standard technique of cascade impaction.
Inline measurements with cascade impaction allow correlations between the two techniques to be easily established.
