A review of current techniques for the evaluation of powder mixing

<p>Blending a mixture of powders to a homogeneous system is a crucial step in many manufacturing processes.To achieve a high quality of the end product, powder mixtures should be made with high contentuniformity. For instance, producing uniform tablets depends on the homogeneous dispersion of activepharmaceutical ingredient (API), often in low level quantities, into excipients. To control the uniformityof a powder mixture, the first required step is to estimate the powder content information during blending.There are several powder homogeneity evaluation techniques which differ in accuracy, fundamentalbasis, cost and operating conditions. In this article, emerging techniques for the analysis of powder contentand powder blend uniformity, are explained and compared. The advantages and drawbacks of all thetechniques are reviewed to help the readers to select the appropriate equipment for the powder mixingevaluation. In addition, the paper highlights the recent innovative on-line measurement techniques usedfor the non-invasive evaluation of the mixing performance.</p>