Observations on the use of Compressed Discs in Dissolution Studies

Abstract

Intrinsic dissolution rates of crystalline and “amorphous” digoxin from compressed discs of the drug show a dependency on the initial particle characteristics, such as specific surface area. Scanning electron microscopy of disc surfaces show that pits appear at the boundaries between.crystals although some fusion has obviously occurred. Presumably these edges act as preferential sites for dissolution. After some dissolution has occurred the disc surface appears microcrystalline and has by no means the same surface area as the starting surface. Some caution has therefore to be applied in the interpretation of dissolution results obtained from compressed discs.