Assessing Hyperspectral Image Content of Pharmaceutical Products Using the Herfindahl–Hirschman Index and Ripley's K-Functions

Hyperspectral chemical imaging technologies are frequently applied in the pharmaceutical industry to assess the distribution of ingredients in product intermediates and finished products. This article discusses two recognized measures of spatial uniformity in the context of pharmaceuticals. Synthetic images are used to introduce the utility of Ripley's K-function and the Herfindahl-Hirschman index (HHI) for describing image content. These metrics were applied to a commercial-like product to demonstrate the practical interpretation for product development. The simple approaches presented here offer the possibility of reporting objective measures of intra-tablet compositional uniformity with minimal supervision.