DETAILED DESCRIPTION OF THE INVENTION According to the present invention, therapeutic dosage forms have now been discovered which are easy to prepare, provide sustained release of contained therapeutic agents and float on gastric fluid.
These unit dosage forms, which are in the form of tablets, although not compressed, have sufficient mechanical stability and hardness so that they will withstand the normal stress of production, packaging and dispensing.
They have a density which is less than one and sufficiently low so that they will float on gastric fluid.
Typically, the density is from about 0.
6 to 0.
95.
The tablets contain as essential ingredients, the therapeutic agent in sufficient concentration to be therapeutically effective, about 0.
5 to 4% of a gelling agent, 10-20% of a therapeutically acceptable inert oil and water.
The optimum concentration of the therapeutic agent in the non-compressed tablet will, of course, vary with the identity of the therapeutic agent and its optimum therapeutic dosage.
Generally, the amount of the agent in the tablet will be from about 50 to about 75% by weight based on the total weight of the tablet.
(All percentages by weight in this disclosure and claims are based on total weight.
) Except for those which must be protected from the gastric fluid, there is practically no limitation to the therapeutic agents which can be administered in accordance with this invention.
They include, for example, analgesics, anorexias, antacids, antibiotics, antidiabetics, antihistamines, steroids, antinauseants, antispasmodies, cardiovascular preparations, decongestants, diuretics, geriatrics, muscle relaxants, tranquilizers and vitamins.
More specific examples include theophylline, acetaminophen, ampicillin, atropine, penicillin, tetracycline, chlorathiazide, phenytoin, riboflavin, quinidine, cimetidine, captopril, indomethicin, prednisolone and estradiol.
The agents can be employed as free bases or as metal or acid addition salts.
The gelling agents which may be used in the present invention are hydrocolloids, i
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Vasodialators 
