Within the pharmaceutical industry, inline near infrared (NIR) spectroscopy is one of the most commonly applied process analytical technologies to monitor content uniformity of powder blends (1).Inline NIR provides direct insight into blending operations with respect to the degree of uniformity of the ingredient of interest either for process development or control during commercialmanufacturing. A quantitative calibration for a specific ingredient may be applied to predict the content of small fractions of the powder blend during the blend process, such as for every revolutionin the case of a rotary blender. The actual size and sampled volume of the powder blend is an important variable for interpretation of NIR results.