Measurement of density variations in tablets using X-ray computed tomography.

In this paper the application of X-ray computed tomography (CT) to measure the material density distribution in pharmaceutical tablets is discussed. X-ray CT is a non-destructive inspection technique which provides cross-sectional images in different planes through a component. The CT image values provide information on the local X-ray attenuation coefficients. For a particular material and X-ray energy, X-ray attenuation is approximately proportional to material density. Determination of quantitative density distributions requires consideration of non-linear instrumental effects including scatter and "beam hardening". Density maps in tablets manufactured under controlled conditions are presented. The results are discussed with reference to the local properties of the material within the tablet and the tablet design features.