Volume of pharmaceutical powders probed by frequency-domain photon migration measurements of multiply scattered light.
Using probability distribution analysis to describe the propagation of multiply scattered light between a point source and point detector located a known distance apart, mathematical expressions predicting the volume of sampled powder were determined for infinite and semi-infinite powder beds and then compared to experimental measurements of frequency-domain photon migration (FDPM). Our results show that the volume of powder sampled varies with optical properties and, when using FDPM techniques, with modulation frequency. For a typical measurement in lactose powder, the volume of powder sampled by multiply scattered light propagating between a 1000-microm-diameter point source and point detector pair separated by 8 mm is predicted to be 1.8 and 1.5 cm3 at modulated frequencies of 50 and 100 MHz, respectively. Experimental measurements in lactose powder confirm the predictions.
Department of Chemical Engineering, Texas A&M University, College Station 77843-3122, USA.
Tianshu
T
Pan
Eva M
EM
Sevick-Muraca
D007785:Lactose / Q000592:standards; D008027:Light; D010316:Particle Size; D011208:Powders / Q000592:standards*; D012542:Scattering, Radiation
D011208:Powders; D007785:Lactose