drug dosage form layered powered by hydrogel

"DRUG DOSAGE FORM IN LAYERS ENGAGED IN HYDROGEL". One form of controlled release dosage for sertraline has a central part which comprises a composition comprising sertraline and a water-swellable composition wherein the water-swellable composition is in a separate region within the central portion. A coating around said central portion is water-permeable, water-insoluble and has at least one opening therethrough. In one embodiment, the dosage form releases sertraline in the use environment at an average speed of 6 to 10 wt% per hour of the second to twelfth hour after introduction into a use environment is less than about 25% by weight during the first two hours and at least 70% by weight after the twelfth hour, which correspond to the percentages released from the compressed drug mass divided by the total mass of drug originally present in the tablet. In another embodiment, the dosage form releases less than about 25% of the sertraline in two hours environment of use after introduction of the dosage form into the use environment and releases at least 25% by weight of the eighth to twenty-fourth hour.