MASS MEDIAN PARTICLE-SIZE DETERMINATION OF AN ACTIVE COMPOUND IN A BINARY MIXTURE USING NEAR-INFRARED SPECTROSCOPY

Near-infrared (NIR) spectroscopy was applied to the determination of t he mass median particle size (mmps) of a micronised active compound co ntained within a lactose monohydrate matrix. The concentration of the active compound was 4% by weight, and covered a mmps range between 8 a nd 20 mu M. Multivariate statistical analysis was applied to zero orde r NIR spectra, using particle size data obtained by laser diffractomet ry as the reference technique. Based upon a limited data set and parti al method validation, principal component regression using three facto rs produced a standard error of calibration in the order of 2 mu m. Du e to the speed, simplicity and low operating costs of this technique, it has been demonstrated that NIR spectroscopy is a viable alternative to methods that have been applied to this particular problem.