Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
2001-05-23
2004-06-15
Kishore, Gohamudi S. (Department: 1615)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
C424S400000, C424S451000, C424S452000, C424S457000, C424S458000, C424S459000, C424S461000, C424S463000, C424S464000, C424S465000, C424S468000, C424S474000, C424S475000, C424S479000, C424S480000, C424S489000, C424S490000, C424S493000, C424S494000, C424S497000
Reexamination Certificate
active
06750249
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a controlled-release oral preparation comprising esculetin or its derivative as an effective component.
Because the controlled-release oral preparation of the present invention can gradually release esculetin or its derivative in a controlled manner over a long period of time, the preparation can maintain the effect of the esculetin or the derivative for a long time by a single administration. As a result, the preparation can improve symptoms such as inflammations, aches, performance disorders, and the like which are induced by a break-down of arthrodial cartilage such as osteoarthropathy, chronic rheumatism, etc.
BACKGROUND ART
Chronic rheumatism, rheumatic fever, osteoarthropathy, and the like are included in the arthropathy. Of these chronic rheumatism and osteoarthropathy are suffered by a great number of patients and thus are considered to be major arthropathy. There are two types of osteoarthropathy; one is congenitus or secondary in nature, and the other is primary and induced by progressive deformation of arthrodial cartilage due to aging. The number of patients suffering from the primary osteoarthropathy has been increasing in recent years as the number of aged people increases. There is a significant difference between the cause of disease and pathology of chronic rheumatism and those of osteoarthropathy. However, these diseases are common inasmuch as the ultimately obstruct joint functions by fracture of the arthrodial cartilage. A primarily chosen medicine for rheumatic diseases such as chronicrheumatism, rheumatic fever, systemic lupus erythematosus, osteoarthropathy, and the like is an analgesicanti-inflammatory agent such as aspirin, indomethacin, or the like. In addition to these medicines, gold preparations such as thiosol, immunomodulating drug, steroid drugs, D-penicillamine, and the like are used as a chronic arthropathy curative medicine. On the other hand, esculetins such as esculetin, 4-methylesculetin and the like are known as medicines possessing a cholesterol reducing effect, vascular reinforcing effect, and anti-oxidation effect (Japanese Patent Publication No. 16626/1967). Carboxylic acid diesters of 4-methyl esculetin having 6-25 carbon atoms, particularly caprylic acid diester lauric acid diester, and palmitic acid diester, are known to exhibit an anti-inflammatory effect (French Patent No. 2276819).
The above conventional analgesic antiinflammation agents not only exhibit no effect of depressing fractures of the arthrodial cartilage, but also some of these agents have been confirmed to have an effect of exacerbating the diseases in an experiment using cartilage cells. Furthermore, no fracture depressant effect of the arthrodial cartilage has been clinically found in the above curative medicines for chronic arthropathy and osteoarthropathy. The arthrodial cartilage consists of cartilage cells and a cartilage matrix. The cartilage matrix has a three-dimensional matrix structure wherein type II collagen which is a cartilage cell-producing fibrous protein and proteoglycan which is a protein polysaccharide composite material, are non-conjunctively bonded and intertwined with hyaluronic acid in a complex manner. The cartilage matrix contains a large quantity of water which contributes to maintaining a normal joint function. The major polysaccharide forming proteoglycan is glycosaminoglycan consisting of chondroitin sulfate and keratan sulfate.
Watanabe et al. found that esculetins such as esculetin, 4-methyl esculetin, and the like strongly depress a decrease in the amount of glycosaminoglycan in the matrix due to stimulation of interleukin-1 and the like, and thus are useful as a protective agent for the arthrodial cartilage. (Japanese Patent Application Laid-open No. 312925/1994).
When orally-administered, these esculetins are immediately metabolized: in the liver and found in blood as a conjugate with glucuronic acid or sulfuric acid. The glucuronic acid conjugate is considered to become esculetin in the arthrodial cartilage and exhibit a cartilage protection effect. However, because the glucuronic acid conjugate has high water solubility and is immediately eliminated from the kidney, there is almost no such substance present in the blood three hours after oral administration. It is necessary for esculetin or a derivative thereof to be continuously present in the cartilage for a long time at a concentration above a certain level (0.01-100, preferably 0.1-10 ng/mg of cartilage) to exhibit the cartilage protection effect, requiring the administration of a large amount of the medicine (200-1,000 mg/kg) several times (6-12 times) a day. Administration of a large amount of the medicine involves a rapid increase in the blood concentration, thereby increasing risks of side effects.
In order to solve these problems, the inventors of the present invention have conducted extensive studies and found that it is possible to continuously maintain the concentration required for the compound to locally exhibit the medical effect (0.01-100, preferably0.1-10ng/mg of cartilage) for a long period of time (10 hours or more) and to reduce side effects at a lower dose than conventional medicines for oral administration by controlling release of esculetin or its derivative from a preparation.
Accordingly, an object of the present invention is to provide a novel arthropathy therapeutic oral preparation comprising esculetin or its derivative which can continuously maintain the local concentration of the effective components by controlled release, even if administered at a small dose, thereby decreasing a risk of side effect.
DISCLOSURE OF THE INVENTION
The present invention has been accomplished to solve these problems and relates to a controlled-release oral preparation such as granules, tablets, capsules, etc. comprising esculetin its derivative, or pharmacologically acceptable salts thereof, which can release the effective components (major medicines esculetin and its derivative) in a controlled manner.
The medicinal effect of esculetin or its derivatives has a correlation with the intracartilaginous concentration of esculetin or its derivatives after administration, esculetin: metabolized from the derivatives, and glucuronic acid conjugates of esculetins which produce esculetin by decomposition with time.
The intracartilaginous concentration of esculetin or its derivatives after administration, esculetin metabolized from the derivatives, and glucuronic acid conjugates of esculetins which produce esculetin by decomposition with time has a correlation with the sum of the blood concentration of esculetin or its derivatives and glucuronic acid conjugates of esculetin or its derivatives. When the sum of: intracartilaginous concentration of esculetin or its derivatives is 0.01 ng/mg of cartilage, the sum of blood concentration of esculetin or its derivatives and 6-position or 7-position glucuronic acid conjugates of esculetin or its derivatives which release esculetin or its derivatives in the cartilage is about 0.5 &mgr;mol/L. Therefore, to maintain the medicinal effect of esculetin or its derivatives, the sum of the blood concentration of esculetin or its derivatives and 6-position or 7-position glucuronic acid conjugates of esculetin or its derivatives which release esculetin or its derivatives in the cartilage must be 0.5 &mgr;mol/L or more.
Because of the above reasons, there are no limitations to the form and formulation for the oral administration preparation of the present invention inasmuch as the preparation comprises esculetin, its derivatives, or pharmacologicalIly acceptable salts thereof as major components, can be orally administered, and, when orally administered to a dog at a dose of 1 to 100 mg/kg, can maintain the blood concentration of 0.5 &mgr;mol/L or more of esculetin or its derivatives and 6-position or 7-position glucuronic acid conjugates of esculetin or its derivatives which release esculetin or its derivatives, in the cartilage for a period of 10 hours or more.
BEST MOBE FOR CARRYING OUT THE INVENTIO
Chiba Tadahiko
Ono Saichi
Yamaguchi Iwao
Hollander Law Firm, P.L.C.
Kishore Gohamudi S.
Kureha Chemical Industry Co. Ltd.
Oh Simon J.
LandOfFree
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