Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Reexamination Certificate
1999-12-13
2001-07-31
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
C424S493000, C424S494000, C424S498000
Reexamination Certificate
active
06267990
ABSTRACT:
The present invention relates to a pharmaceutical preparation with which it is possible to achieve improved release of active ingredient as a function of time and of the pH value of the surroundings. The invention relates especially to such a preparation comprising an ACE (angiotensin converting enzyme) inhibitor as active ingredient, especially comprising captopril.
Slow-release pharmaceutical dosage forms for the controlled and delayed release of captopril are known. For example, U.S. Pat. No. 5,158,777 describes a composition in which a portion of the active ingredient (captopril) is released immediately and a second portion is released in a delayed manner. That is achieved, according to Example 2, by the provision of two different types of pellet, of which one type of pellet, containing active ingredient, is uncoated, while the other type, containing active ingredient, has a core comprising, inter alia, captopril and ascobic acid, the core being coated with a methacrylic acid polymer (EUDRAGIT® RS) which causes the active ingredient to be released in a delayed manner.
Other slow-release forms of captopril include, for example, according to U.S. Pat. No. 4,666,705 an uncoated tablet containing an acrylic acid polymer; according to U.S. Pat. No. 5,738,850 a preparation containing captopril in combination with chitosan; and according to U.S. Pat. No. 4,756,911 a coated tablet comprising a core containing, for example, captopril as active ingredient (column 4, line 57), one or more water-soluble or water-swellable primary hydrocolloidal swelling agents containing methoxy groups, one or more secondary hydrocolloidal swelling agents, one or more non-swellable binders and/or waxes, and one or more lubricants.
It has been found, however, that the prior art is in need of improvement in that the active ingredient is released prematurely according to the prior art and thus leads to a therapeutic plasma level that has too short a duration. In addition, in some slow-release forms the coatings may not have dissolved sufficiently to release the active ingredient when the tablet has reached the intestine so that the active ingredient is excreted before it is absorbed from the stomach/intestinal tract, since no further absorption takes place in the large intestine.
Investigations underlying the invention have shown that although formulations according to the prior art exhibit retarding effects in vitro, it is not possible in vivo to obtain a constant and therapeutically effective blood level concentration over a prolonged period, or to achieve prolonged ACE inhibition.
The problem underlying the invention is to provide a pharmaceutical preparation, especially a preparation comprising an ACE inhibitor as active ingredient, for example comprising captopril, that permits controlled release of the active ingredient, especially in the case of a single dose, and thus ensures over a prolonged period a therapeutically effective blood level with minimal variations in the blood level concentration, and that meets the requirement that the action should begin immediately and, furthermore, that permits prolonged ACE inhibition.
To that end there is provided according to the invention a pharmaceutical preparation which comprises or consists of the following components:
(i) an initial dose of active ingredient, which is provided by the active ingredient as desired in the form of a powder, granules and/or pellets, in each case together with optional excipients,
(ii) a first delayed-release type of pellet, in which the active ingredient and optional excipients are covered with a coating, and
(iii) a second delayed-release type of pellet, in which the active ingredient and optional excipients are again covered with a coating,
wherein the active ingredient is an ACE inhibitor, and
wherein the amounts of the coatings according to (ii) and (iii) are present in a ratio, based on weight, within the range of from 1:2 to 1:7.
With the preparation according to the invention it has been found, with captopril as active ingredient, that blood level concentrations with extremely small variations can be established in vivo and, moreover, that the action of the medicament begins almost immediately. Surprisingly, the active ingredient is released from the preparation according to the invention in such a manner that pronounced blood level peaks at the beginning are avoided and yet therapeutically effective blood concentrations are maintained over a long period of time. Above all it has been found, surprisingly, that ACE inhibition of above average duration can be achieved.
In the preparation according to the invention, the amounts of the coatings according to (ii) and (iii) may be present in a ratio, based on weight, of approximately 1:5.
The active ingredient is, therefore, an ACE (angiotensin converting enzyme) inhibitor, especially captopril, moexipril, perindopril, quinapril, ramipril, spirapril, tandolapril, mixtures thereof and/or their pharmaceutically acceptable salts, for example hydrochlorides, for example perindopril erbumine.
The active ingredient content of the initial dose may be from 5 to 30% by weight of the total active ingredient content.
In the initial dose, the active ingredient may be in the form of a powder, granules and/or in the form of a pellet, it being possible for granules and pellets to contain customary excipients.
Pellets of the first and second delayed-release types can be obtained by providing pellets which may have been prepared for an initial dose with the respective coating.
The coating for the first and second types of delayed-release pellet may be a coating that is resistant to qastic juices, especially based on polymethacrylic acid, more especially on EUDRAGIT® S. In a preferred embodiment, the same coating material is chosen for the first and second types of delayed-release pellet.
In a preferred embodiment, the coating for the first and second types of delayed-release pellet has, apart from polymethacrylic acid, no other component of equal or greater acidity.
The coating for the first and/or second type(s) of delayed-release pellet may comprise customary film-forming agents and/or excipients, especially dibutyl phthalate, polyethylene glycol, triethyl citrate (CITROFLEX®), ethyl cellulose (AQUACOAT®) titanium dioxide and/or hydroxypropylmethyl cellulose. Microcrystalline cellulose and/or lactose may come into consideration as excipients.
The ratio by weight of initial dose to first type of delayed-release pellet to second type of delayed-release pellet may be within the range of from 1:1:1 to 1:10:10 and may be especially approximately 1: approximately 1: approximately 2.
The preparation according to the invention can be characterised by the following proportions by weight:
initial dose: from 10 to 30% by weight,
first type of delayed-release pellet: from 20 to 40% by weight, and
second type of delayed-release pellet: from 40 to 60% by weight,
the sum of all three components being 100% by weight; it can be characterised especially by
initial dose: approximately 22.9% by weight,
first type of delayed-release pellet: approximately 25.8% by weight, and
second type of delayed-release pellet: approximately 51.3% by weight,
the sum of all three components being 100% by weight.
The preparation according to the invention may be in the form of a capsule, especially a gelatin capsule, the capsule comprising all three components. Such a capsule may comprise an amount of active ingredient required for a daily dose or for a single dose. For example, a capsule may comprise an amount of captopril required for the daily dose or single dose, especially in the range of from 25 to 300 mg, more especially from 50 to 200 mg and very especially from 75 to 150 mg.
The initial dose of captopril, based on a daily dose or a single dose, may be from 5 to 30 mg.
The active ingredient content of the pellets may be from 10 to 50%, it being possible to use customary excipients for pellet formation, such as microcrystalline cellulose and/or lactose, and it being possible for the pellets of the three components to
Fischer Wilfried
Klokkers Karin
Oppelt Renate
Hexal AG
Marshall O'Toole Gerstein Murray & Borun
Page Thurman K.
Tran S.
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