OBJECTIVETo develop a colon position pulsatile capsule drug delivery system of which the lag-time is controlled by a plug tablet mainly made of konjac glucomannan and evaluate its release profile in vitro.

METHODImpermeable capsule body was prepared by filling method, the plug tablet was pressed by direct compression, and the rapid-disintegrable drug tablets was made by wet granulation. The pulsatile capsules were prepared by putting the drug tablet into the impermeable body and sealed it with the plug tablet The factors affecting the lag-time were investigated by dissolution testing.

RESULTThe formulation of the rapid-disintegrable drug tablets influenced the pulsatile release of the drug, the composition of the plug tablet significantly influenced the lag-time; the lag-time was extended with the higher viscosity of HPMC and the increased proportion of konjac glucomannan.

CONCLUSIONThe pulsatile capsule with a suitable lag-time and colon position characteristics can be achieved by adjusting the composition of the plug tablet.