In this study, the potential of micro-focus X-ray (MFX) imaging as a tool in the design and quality control of drug delivery systems has been demonstrated. MFX imaging has been used to map the spatial distribution of a drug down to length-scales of approximately 10-100 microm and has shown that the spatial distribution of the drug amiodarone within a hydroxypropylmethylcellulose (HPMC) controlled release tablet (diameter 10 mm) is not homogeneous. MFX imaging allows an assessment to be made of the degree of mixing of the original powders. Despite vigorous mixing during the manufacture of the tablets, the drug particles, originally of size 180-420 microm, were found to be concentrated within isolated but spatially extended patches of sizes up to 1 mm that were scattered across the tablet.