Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Reexamination Certificate
2001-07-16
2003-04-22
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
C424S464000, C424S490000, C424S468000, C424S469000, C424S486000, C424S487000, C514S159000, C514S166000
Reexamination Certificate
active
06551620
ABSTRACT:
The present invention relates to a pellet formulation for the treatment of the intestinal tract, which comprises, as a pharmaceutical active compound, aminosalicylic acid or a pharmaceutically tolerable salt or derivatives thereof.
The active compound aminosalicylic acid (in particular 5-ASA) or its derivatives have been used successfully for a relatively long time for the treatment of intestinal disorders, such as, for example, ulcerative colitis and Crohn's disease (DE 31 51 196 A1).
The use of 5-ASA and its derivatives as a chemotherapeutic agent in colonic cancer is likewise known, polyps in the colon and rectum being associated with an increased risk of carcinoma (WO 95/18622).
A coloscopic polypectomy in patients with polyps in the colon and/or rectum results in a considerable reduction in risk of the formation of colonic carcinomas and is recommended as a therapy, in particular in the case of colorectal polyps. The reccurrence rate after polypectomy, however, is high and amounts to about 6-30% per year. Aminosalicylic acid is suitable for the longer-term treatment of such patients and lowers the reccurrence rate of colorectal polyps.
The action of aminosalicylic acid in the treatment of intestinal disorders, or in the prevention of their recurrence or in the prevention of secondary disorders arising therefrom and possible accompanying disorders takes place by means of the contact of the active compound directly at the site of the disorder in the intestine, the action of the aminosalicylic acid, or a derivative thereof, being directly related to its local concentration in the intestinal area to be treated.
Since inflammatory processes often affect relatively large sections of the intestinal tract, the pharmaceutical form should spread reproducibly over wide areas of the intestine and release the active compound only at the site of inflammation.
A problem in the treatment with aminosalicylic acid is that the active compound is very easily absorbed and can be excreted via the kidney before its action can occur.
In the prior art, tablets and pellets are known which are coated with an enteric coating in order to thus prevent a premature release of the active compounds.
FR-A2 692 484 discloses a tablet for the controlled release of 4-ASA in a hydrophilic matrix which consists of swellable polymers forming a gel barrier, and having an enteric coating. After dissolution of the coating, the matrix swells and forms a gel barrier through which the active compound diffuses out. After an approximately two-hour lag phase, the composition disclosed in FR-A 2 692 484 releases the active compound approximately linearly in the intestine over a period of time of a further 14 h.
EP 0 453 001 A1 discloses a pharmaceutical composition in which the active compound is covered with at least two membranes, of which one is soluble at a pH of ≧5.5 and the other is insoluble at this pH but is permeable to the intestinal fluids.
EP 0 148 811 A1 discloses a pharmaceutical composition which consists of a core which contains the active compound. The core is surrounded by two layers, of which the inner layer is a diffusion membrane and the second layer is an anionic polymer and/or a fatty acid having a pK
a
of 4.5 to 7.
EP 0 629 398 A1 discloses pharmaceutical compositions in which the active compound-containing core is surrounded by an enteric phase. According to Example 2, the core can contain small amounts of hydroxypropyl-cellulose. The active compound should be released rapidly after dissolution of the enteric phase.
EP 0 485 840 A2 discloses an oral pharmaceutical form which contains a shell material surrounding the active compound consisting of a polysaccharide and a film-forming polymer material.
A disadvantage in the case of the pharmaceutical formulations known in the prior art is that the active compound is also absorbed into the blood circulation. This amount of active compound is thus lacking in the intestine, so that the effective dose of the medicament is reduced by the part of the active compound which is found in the blood.
Moreover, patients who suffer from intestinal disorders frequently have to be further treated over relatively long periods with the active compound, or derivatives thereof, after the acute disorder has died down in order to prevent the disorder flaring up again or secondary disorders resulting from the original disorder. In the case of such a long-term treatment, however, it has proven to be a problem that a certain nephrotoxicity of systemically available 5-ASA, i.e. 5-ASA found in the bloodstream, or derivatives thereof cannot be excluded (M. Barry, Prescribers Journal, 1992, 32, 205).
It is thus an object of the present invention to make available an orally administrable pharmaceutical formulation which does not have these disadvantages. According to the invention, formulations are therefore made available which have a controlled release profile which results in a high local active compound concentration at the site of action and simultaneously guarantees a blood level of the active compound which is as low as possible.
In the context of the present invention, it has now been found that pellet formulations are particularly suitable for this purpose, since unlike a tablet they spread the pharmaceutical form reproducibly over wide areas of the intestine and are thus particularly suitable for treatment of inflammatory processes, which often affect relatively large sections of the intestinal tract. In order to achieve the necessary local active compound concentration, the active compound must in this case be released at the site of inflammation within a relatively short time (up to a few hours) without, however, it being released virtually immediately, in order that its action does not wear off too rapidly.
The use of a swellable, gel-forming matrix such as described in FR-A 2 692 484 is not suitable for pellets having a diameter of ≧3 mm, since on account of the small diameter the polymer is very rapidly penetrated by the water, eroded as a result, and the active compound would thus be released virtually immediately (about 30 min).
In the context of the present invention, however, it has surprisingly been found that, if the active compound is present in the pellet core in a non gel-forming polymer matrix which is essentially insoluble and permeable to intestinal fluids and the active compound, a markedly reduced release of the active compound into the blood, with simultaneously increased local concentration of the active compound at the site of the disorder in the intestine, is guaranteed in comparison with aminosalicylic acid formulations already known in the prior art.
The present invention thus relates to an orally administrable pharmaceutical pellet formulation having a controlled release profile for the treatment of the intestinal tract, which comprises a core and an enteric coating, and, if appropriate, further pharmaceutically tolerable additives, the core including as a pharmaceutically active compound aminosalicylic acid or a pharmaceutically tolerable salt or derivative thereof, wherein the active compound is present in the core in a non gel-forming polymer matrix which is essentially insoluble in the intestinal tract and permeable to intestinal fluids and the active compound, the matrix-forming polymer making up at least 1% by weight of the total weight of the core.
The invention furthermore relates to a process for the production of the pellets described above and their use for the production of a medicament for the treatment of intestinal disorders, such as inflammatory intestinal disorders, preferably in the active phase and/or in the remission phase, for the prevention of these disorders, for the prevention of the recurrrence of these disorders or secondary disorders resulting therefrom, and of possible accompanying disorders and also for the treatment of intestinal cancer. The medicament is particularly suitable for the treatment of inflammatory intestinal disorders such as Crohn's disease and ulcerative colitis, and for the preventi
Dr. Falk Pharma GmbH
Page Thurman K.
Pulliam Amy E
Schwegman Lundberg Woessner & Kluth P.A.
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