Utilizing USP <429> — Light Diffraction Measurements Of Particle Size

Laser diffraction has become the most widely used particle characterization technique in the pharmaceutical industry. The USP <429> test is the first attempt by this industry to provide guidance on using this technique. The origin of USP <429> begins with the ISO 13320 standard "Particle size analysis — Laser diffraction methods — Part 1: General principles."

From there, the EP (the lead group for this effort) published test EP 2.9.31 "Laser Diffraction Measurement of Particle Size." The first appearance in the US came in Pharmacopeial Forum 28, Number 3 2002. The method is now published in USP 28, NF 25 and is in stage 4 of the harmonization process as of mid-2007.

This application note attempts to help pharmaceutical companies plan to incorporate USP <429> into their current and future particle size analysis methods.