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Nasal sprays typically produce droplets in the range 20-200 microns which is outside the effective range of inertial impactors. For this reason, the droplet size distribution of nasal sprays and aerosols is normally determined by means of laser diffraction.
At the same time, however, most sprays deliver a proportion (typically <5%) of fine droplets in the <10 micron range.
It is important to quantify this “fine particle dose” since it can penetrate beyond the nasal tract and into the lower respiratory tract or lungs, which may prove undesirable.
For this reason, the FDA recommends the use of a cascade impactor in conjunction with a high volume expansion chamber to measure the amount of drug in small particles or droplets in respect of nasal sprays and the particle/droplet size distribution in the case of nasal aerosols.
In accordance with the draft guidance, Copley Scientific now offer a range of glass expansion chambers to be used with either the Andersen Cascade Impactor or Next Generation Impactor to meet these requirements.
For comprehensive product details, specifications and part numbers, please request a copy of our brochure “Quality Solutions for Inhaler Testing”.
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