Dry coating is an innovative technique in which nano particles are mechanically coated onto the surface of larger (from a micron to few microns) host particles to impart useful properties to the final product, which are engineered particles. Dry coated engineered particles can have improved flow and handling properties, and hence are very useful for a number of industrial applications. In this work, we present preparation, characterization and applications of such engineered particles to pharmaceutical applications.

A current need has arisen to characterize these dry coated powders, specifically active pharmaceutical ingredient powders. These powders were coated with nanoparticles using three different methods: the MAIC, the v-blender and the sieve. These powders, both before and after modification, need characterization, especially with respect to flow, to measure the improvement made by the dry coating. Powder flow is a critical parameter in both manufacturing and formulation.

The NIR is a viable method to do so with little trouble. NIR spectroscopy has been used to determine the flow of powders. By collecting spectra of voiding powders and determining the time per spectra, an accurate in line flow monitoring measurement can be taken and a qualitative flow rate measurement can be determined. Additionally, the NIR can give useful information, such as a qualitative flow rate, and can also differentiate the differences and consistency of the flow. This can help to compare the original uncoated powder and the nanocoated powder. The method can also compare the different methods used during the dry coating process. Other commercial characterization methods are not as useful, as they are offline tools and are often time consuming and do not give a direct flow measurement. Using this NIR method, spectra were obtained for blends of powder using non-coated API and then again using API coated with nanoparticles. Using the spectral data, the numerical flow rate of the voiding blends can be calculated.