Gadobenic acid (

INN Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway; before the advent of motorized transportation they also provided accommo ...

, brand name Multihance) is a complex of

gadolinium Gadolinium is a chemical element with the symbol Gd and atomic number 64. Gadolinium is a silvery-white metal when oxidation is removed. It is only slightly malleable and is a ductile rare-earth element. Gadolinium reacts with atmospheric oxygen ...

with the

ligand In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's elec ...

BOPTA. In the form of the methylglucamine salt meglumine gadobenate ( INNm) or gadobenate dimeglumine (

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), it is used as a gadolinium-based MRI contrast medium. BOPTA is a derivative of

DTPA Pentetic acid or diethylenetriaminepentaacetic acid (DTPA) is an aminopolycarboxylic acid consisting of a diethylenetriamine backbone with five carboxymethyl groups. The molecule can be viewed as an expanded version of EDTA and is used similar ...

in which one terminal

carboxyl group In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...

, –C(O)OH is replaced by -C–O–CH₂C₆H₅. Thus gadobenic acid is closely related to

gadopentetic acid Gadopentetic acid, sold under the brand name Magnevist, is a gadolinium-based MRI contrast agent. It is usually administered as a salt of a complex of gadolinium with DTPA (''d''iethylene''t''riamine''p''ent''a''cetate) with the chemical formul ...

. BOPTA itself was first synthesized in 1995. In the "gadobenate" ion gadolinium ion is 9-

coordinate In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as Euclidean space. The order of the coordinates is sign ...

with BOPTA acting as an 8-coordinating ligand. The ninth position is occupied by a water molecule, which exchanges rapidly with water molecules in the immediate vicinity of the strongly

paramagnetic Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, ...

complex, providing a mechanism for MRI contrast enhancement. ¹³⁹La NMR studies on the diamagnetic La-BOPTA²⁻ complex suggest that the Gd complex maintains in solution the same kind of coordination as found, by

X-ray crystallography X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...

, in the solid state for Gd-BOPTA disodium salt.

References

External links

* * MRI contrast agents Organogadolinium compounds {{pharmacology-stub