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Process for the preparation of tablets with retarded liberation of the active agent is predetermined
| Details |
Inventors: Sothmann, Gunnar A.; Marttila, Esko V.;
Assignee: Orion-yhtyma Oy (FI)
Primary Examiner: Friedman; Stanley J.
Assistant Examiner:
Attorney, Agent or Firm: Burns, Doane, Swecker & Mathis
A process for the preparation of matrix-type tablets with retarded liberation of the active agent. The liberation of the active agent from the tablets takes place at a speed that has been adjusted precisely in advance. In the granulation process, polymethacrylate plastics insoluble in neutral or slightly acid water either as dissolved in an organic solvent or as a water dispersion are used as the retarding matrix substance. Before the tablets are compressed, an ester of a large-molecule fatty acid or a product obtained from same by means of hydrogenation is mixed into the grain mix in order to adjust the rate of liberation of the active agent. |
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DETAILED DESCRIPTION What we claim is: 1.
Process for the preparation of controlled release tablets containing an active agent comprising: (a) granulating the active agent with an organic solvent solution or a water dispersion of a copolymerizate of acrylic and methacrylic acid esters containing quaternary ammonium groups or an anionic copolymerizate of methacrylic acid and methyl ester of methacrylic acid; (b) mixing the granules with an ester of a fatty acid containing 10 to 30 carbon atoms, said ester being present in an amount less than 15% of the total weight of the mixture whereby the granules are coated with said ester; and (c) compressing the resulting mixture into tablets whereby the tablets release the active agent at a rate which is substantially independent of the compression pressure.
2.
A process as claimed in claim 1, characterized in that a water dispersion of a copolymerizate of methyl and ethyl esters of acrylic and methacrylic acid with neutral character is used as the retarding matrix substance.
3.
A process as claimed in claims 2 or 1, characterized in that the fatty acid ester is hydrogenated castor oil or hydrogenated cotton seed oil.
Description:
The subject of the present invention is a process for the preparation of such tablets in which the active agent can be made to become free from the tablet at a controlled speed and which speed of liberation can be set at the same level from batch to batch.
When a pharmaceutical substance is administered orally, it may have detrimental effects which should be avoided.
The occurrence of these side effects can often be reduced by technological means by bringing the preparation into such a form from which the active agent is liberated more slowly than normally.
The active agent may irritate the alimentary canal locally when high concentrations of the active agent come into contact with the intenstinal walls.
In such cases, when the liberation of the active agent from the preparation is made appropriate so that its absorption and its liberation from the preparation are in a correct proportion, the irritating effect can often be avoided
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