Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Tablets – lozenges – or pills
Reexamination Certificate
1998-08-12
2001-06-12
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Tablets, lozenges, or pills
C424S400000, C424S464000, C424S489000, C424S493000, C252S391000, C514S777000, C514S964000
Reexamination Certificate
active
06245354
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a drug delivery system using a galactoxyloglucan, that is, to a drug sustained release preparation containing as a sustained release ingredient a partial degradation product of the galactose moiety of a galacto-xyloglucan and a method for the sustained release of a drug thereby. More particularly, the present invention provides a drug sustained release preparation which can gradually release the drug in biobody by utilizing thermally reversible gel (or thermoreversible gel) behavior of the galactose-partial degradation product of a galactoxyloglucan, which is produced by partially removing a galactose moiety on the side-chain from a galactoxyloglucan with an enzyme, and also provides a method of gradually releasing a drug by using the galactose-partial degradation product of a galactoxyloglucan.
PRIOR ART
The so-called drug delivery system (abbreviated as DDS), that is a technique for maintaining a constant blood level of a drug for a long period of time by administrating of a drug into body, or for maintaining an optimal concentration of a drug in the target organ specifically and further for a long period of time, is important in order to enhance the effect of the drug, and to diminish a side effect so as to use the drug safely. A pharmaceutical preparation defined as a sustained release preparation is known as one of such techniques, and the development of a sustained release preparation being capable of controlling the release of drugs at the most suitable release rate and concentration is important no less than the development of a new drug.
Various new forms of a pharmaceutical preparation are known as such a drug sustained release preparation, which include forms approached from technological aspect, such as those utilizing a thin membrane of a polymer or utilizing a deformated surface of a solid material and further forms approached from biological aspect, such as those utilizing as a carrier a liposome, an emulsion or a polylactic acid.
As a pharmaceutical preparation being capable of sustaining release of a drug, a hydrogel preparation using various hydrogels as a sustained release ingredient has been proposed, for instance, a hydrogel preparation comprising a core composed of a drug and a water-soluble polymer, and an outer layer of a base material comprising a water-soluble polymer (JP-A-63-215620), and a composite drug prepared by incorporating a peptide into a polysaccharide (JP-A-5-38635). Furthermore, it is reported to use a suppository using as a sustained release ingredient, Pluronic, a polyoxyethylene-polyoxypropylene copolymer which is in the form of a sol at a low temperature but is gelled at a body temperature [S. Miyazaki et. al., Chem. Pharm. Bull., 32, 4205 (1984)].
The conventional attempts using a polymer having gelling property as a gel base for a drug (a sustained release ingredient) have some problems such as a difficulty of the infusion into the body or being painful due to high viscosity in any dosage form such as oral administration, rectal administration with a suppository etc. or injection.
A gel base for DDS, which maintains a suitable shape in a body and enables to exhibit the sustained release properties, is desired to have the characteristic that it has a low viscosity and is liquid or a sol when infused, and it is thickened and gelled at around the body temperature. The above-mentioned synthetic polymer, Pluronic, is known as such a gel base, but it must be used in a high concentration such as 20 to 30% for gelation. On the other hand, for oral administration, the dosage shall be at the most about several hundreds of mg per kg in view of safety, and the amount in the safe range is not necessarily suitable to the desired sustained release preparation in the scope of safety.
An object of the present invention is to provide a sustained release preparation using a natural polysaccharide which is safe for a body as a gel base (a sustained release ingredient) for DDS and a method for effecting sustained release of a drug.
SUMMARY OF THE INVENTION
The gel base (a sustained release ingredient) useful for DDS have preferably the following characteristics; 1) it is originated from nature to be safeful for the body, 2) it can be gelled even in a low concentration, 3) it has a low viscosity at room temperature and is liquid or a sol when infused and it is thickened and gelled at a body temperature within the body. The present inventors have intensively studied to produce a gel base satisfying the above characteristics from natural polysaccharides which are safe for a body, and as a result, have found that the partial degradation product of the galactose moiety of a galactoxyloglucan, which is produced by removing a part of galactose moieties from a galactoxyloglucan (hereinafter, it is optionally referred to a merely as “galactose-partial degradation product”), is useful as a gel base. That is, the present invention provides a drug sustained release preparation which is produced by incorporating of a drug into the galactose-partial degradation product to be used as a gel base. The present invention provides also a method of controlling release of a drug by incorporating the galactose-partial degradation product as a sustained release ingredient into a drug-containing preparation.
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S. Miyazaki et al. “Pluronic F-127 Gels as a Vehicle for Topical Administration of Anitcancer Agents”, Chem. Phar. Bull., vol. 32, No. 10, pp. 4205-4208, 1984.
Miyazaki Shozo
Shirakawa Mayumi
Yamatoya Kazuhiko
Channavajjala Lakshmi
Dainippon Pharmaceutical Co., Ltd.
Page Thurman K.
Wenderoth , Lind & Ponack, L.L.P.
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