Determining drug spatial distribution within controlled delivery tablets using MFX imaging

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 .apprx.10-100 micro m and has shown that the spatial distribution of the drug amiodarone within a hydroxypropylmethylcellulose (HPMC) controlled release tablet (diam. 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 manuf. of the tablets, the drug particles, originally of size 180-420 micro m, were found to be concd. within isolated but spatially extended patches of sizes up to 1 mm that were scattered across the tablet.