The data set comprises the micro-CT data for the publication Brands et al. (2025). In a joint work within the 1st funding period of the SPP2364, the three-dimensional distribution of the active ingredient in pharmaceutical tablets is investigated using a segmented CT image data set of a tablet. The data published here contains the raw, reconstructed micro-CT image data after acquisition using the Zeiss Xradia Versa 510. Imaging was performed by stitching five individual, overlapping region of interest scans over the full width of the tablet. Additionally, the data set of the segmented active ingredient particles is included in a downscaled version. Further information can be found in the corresponding publication "Penetration depth and effective sample size characterization of UV/Vis radiation into pharmaceutical tablets".