Abstract: The present invention provides a novel amphiphilic substance, a nanoparticle using the novel amphiphilic substance, which can be used as a nanocarrier having high biocompatibility, a drug delivery system and a probe useful for the system, and, a molecular imaging system and a probe useful for the system. An amphiphilic block polymer comprising a hydrophilic block; and a hydrophobic block, wherein the hydrophilic block is a hydrophilic polypeptide chain having 10 or more sarcosine units, and the hydrophobic block is a hydrophobic molecular chain comprising units selected from the group consisting of amino acid units and hydroxyl acid units as essential structural units, and having 5 or more of the essential structural units.

Abstract: The anthranilic acid derivative or the salt thereof represented by the general formula wherein R1 and R2 are hydrogen atom, or the like; R3 is a phenyl, cycloalkyl or bicyclic heterocyclic group which may be substituted, or the like; R4 is a phenyl, cycloalkyl or pyridyl group which may be substituted, or the like; X1 is an alkylene or alkenylene group which may be substituted or a bond; X2 is the general formula —X3—X4— or —X4—X3—, wherein X3 is a sulfur atom, an imino group or a bond, or the like; X4 means an alkylene or alkenylene group which may be substituted or a bond; is useful for a remedy such as rheumatoid arthritis, osteoarthritis and carcinoma, because it shows MMP—13 production inhibitory effect.

Abstract: An anthranilic acid derivative represented by the general formula (X) [wherein R1 represents hydrogen or a carboxy-protecting group; R2 represents optionally substituted phenyl, a heterocyclic group, etc.; R3 represents optionally substituted phenyl, a monocyclic heterocyclic group, etc.; X1 represents carbonyl, etc.; X2 represents optionally substituted alkylene group, a bond, etc.; X3 represents oxygen, a bond, etc.; and X4 represents a group represented by the general formula —X5—X6— or —X6—X5— (wherein X5 means oxygen, a bond, etc.; and X6 means optionally substituted alkylene, a bond, etc.)] or a salt of the derivative. The derivative or salt has the inhibitory activity of MMP-13 production and is hence useful as a therapeutic agent for articular rheumatism, osteoarthritis, cancer, etc.

Abstract: An anthranilic acid derivative represented by the general formula (X) [wherein R1 represents hydrogen or a carboxy-protecting group; R2 represents optionally substituted phenyl, a heterocyclic group, etc.; R3 represents optionally substituted phenyl, a monocyclic heterocyclic group, etc.; X1 represents carbonyl, etc.; X2 represents optionally substituted alkylene group, a bond, etc.; X3 represents oxygen, a bond, etc.; and X4 represents a group represented by the general formula -X5-X6- or -X6-X5- (wherein X5 means oxygen, a bond, etc.; and X6 means optionally substituted alkylene, a bond, etc.)] or a salt of the derivative. The derivative or salt has the inhibitory activity of MMP-13 production and is hence useful as a therapeutic agent for articular rheumatism, osteoarthritis, cancer, etc.

Abstract: The anthranilic acid derivative or the salt thereof represented by the general formula wherein R1 and R2 are hydrogen atom, or the like; R3 is a phenyl, cycloalkyl or bicyclic heterocyclic group which may be substituted, or the like; R4 is a phenyl, cycloalkyl or pyridyl group which may be substituted, or the like; X1 is an alkylene or alkenylene group which may be substituted or a bond; X2 is the general formula -X3-X4- or -X4-X3-, wherein X3 is a sulfur atom, an imino group or a bond, or the like; X4 means an alkylene or alkenylene group which may be substituted or a bond; is useful for a remedy such as rheumatoid arthritis, osteoarthritis and carcinoma, because it shows MMP-13 production inhibitory effect.

Abstract: The present invention provides a novel amphiphilic substance, a nanoparticle using the novel amphiphilic substance, which can be used as a nanocarrier having high biocompatibility, a drug delivery system and a probe useful for the system, and, a molecular imaging system and a probe useful for the system. An amphiphilic block polymer comprising a hydrophilic block; and a hydrophobic block, wherein the hydrophilic block is a hydrophilic polypeptide chain having 10 or more sarcosine units, and the hydrophobic block is a hydrophobic molecular chain comprising units selected from the group consisting of amino acid units and hydroxyl acid units as essential structural units, and having 5 or more of the essential structural units.