A novel compression-coated doughnut-shaped tablet design for zero-order sustained release.

A novel coated doughnut-shaped tablet is evaluated as to its ability to be manufactured in a reproducible manner, and as to whether it releases model drugs at a zero-order rate. The doughnut-shaped tablets were compressed using specially designed punches, which make automated production feasible. In the preliminary part of the experiment, HPMC K15M mixed with gelatin was found to be the most suitable coating tablet material with respect to its disintegration and adherence properties.