Compositions – Magnetic – With wax – bitumen – resin – or gum
Patent
1999-03-01
2000-12-26
Koslow, C. Melissa
Compositions
Magnetic
With wax, bitumen, resin, or gum
252 6252, 252 6254, 536113, 536121, 424 9322, 424 9364, 424 936, 424493, C08L 500, C08K 308, C08B 3700, A61K 4906
Patent
active
061653780
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a complex of a polysaccharide derivative which is substituted with both substituents of a carboxyalkyl group and an unsubstituted or substituted aminoalkyl group with a magnetic metal oxide, a production process for the same and a use thereof.
BACKGROUND ART
Complexes of polysaccharides or polysaccharide derivatives with magnetic metal oxides are proposed in order to improve stability and toxicity of aqueous magnetic sols. Disclosed in, for example, Japanese Patent Publication 13521/1984 (U.S. Pat. No. 4,101,435) are a complex of dextran or dextran modified with sodium hydroxide with magnetic iron oxide of a colloidal size and in U.S. Pat. No. 4,452,773, magnetic iron oxide microspheres obtained by covering magnetic iron oxide particles having a particle diameter of 10 to 20 nm with dextran. Further, complexes of carboxyalkyl ethers of polysaccharides with magnetic iron oxide having a particle diameter of 2 to 100 nm are disclosed in Japanese Patent Application Kokai (Laid-Open) 134001/1991 (U.S. Pat. No. 5,204,457). These complexes are useful as an MRI contrast medium, particularly an MRI contrast medium for liver but have several points to be improved in order to use them as an MRI contrast medium for other organs or sites.
Accordingly, the present investors have prepared a complex of a polysaccharide derivative having both substituents of a carboxyalkyl group and an unsubstituted or substituted aminoalkyl group with a magnetic metal oxide and administered it into a blood flow in the form of an aqueous sol to find that it has a slow blood clearance (slow removal from blood) and a low toxicity and is very useful as a nuclear magnetic resonance imaging (hereinafter abbreviated as MRI) contrast medium, particularly a contrast medium for a blood vessel, and thus have come to complete the present invention.
DISCLOSURE OF THE INVENTION
Thus, the present invention provides a complex of a polysaccharide derivative obtained by carboxyalkyl-etherifying or unsubstituted or substituted aminoalkyl-etherifying a polysaccharide (the above carboxy group and/or amino group may be of a salt form) with a magnetic metal oxide.
The complex of the present invention shall be explained below in further details.
The polysaccharide derivative (hereinafter referred to merely as a polysaccharide ether derivative) having both substituents of a carboxyalkyl ether group and an unsubstituted or substituted aminoalkyl ether group (the above carboxy group and/or amino group may be of a salt form, hereinafter the same) which is one component for constituting the complex of the present invention can be produced by carboxyalkyl-etherifying and an unsubstituted or substituted aminoalkyl-etherifying (hereinafter referred to as aminoalkyl-etherification) a polysaccharide by a method known per se. The order of carboxyalkyl-etherification and aminoalkyl-etherification shall not specifically be restricted, and from the viewpoint that the substitution rates of both substituents can easily be determined, the carboxyalkyl-etherification is preferably carried out first.
The carboxyalkyl-etherification of a polysaccharide can readily be carried out by, for example, adding an alkali to an aqueous solution or a suspension of the polysaccharide (this may be aminoalkyl-etherified in advance by the following method) and then adding monohaloalkylcarboxylic acid, particularly monochloroalkylcarboxylic acid to react them according to conventionally known methods, for example, methods described in U.S. Pat. No. 2,746,906, U.S. Pat. No. 2,876,165 and KOGYO KAGAKU ZASSHI (Japanese Journal of Industrial Chemistry) 68, 1590 (1965). Further, the aminoalkyl-etherification of a polysaccharide or a carboxyalkyl-etherified polysaccharide can be carried out as well by, for example, adding an alkali to an aqueous solution or a suspension of the polysaccharide or the carboxyalkyl-etherified polysaccharide and then adding unsubstituted or substituted aminoalkyl halide or corresponding epoxide, or unsubstituted or subs
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Hanaichi Takamasa
Hasegawa Masakatsu
Kito Kyoji
Maruno Shigeo
Murase Katsutoshi
Koslow C. Melissa
Meito Sangyo Kabushiki Kaisha
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