Patent ID: 6991778

Claim:
In a method of enhancing the image obtained by MRI of the joint of an animal which comprises the step of injecting into the joint, prior to or during the MRI scan thereof, in admixture with a non-toxic pharmacologically acceptable sterile aqueous vehicle, a non-toxic amount effective to enhance the MR image thereby obtained by the scan, of a water soluble nitroxyl-functionalized dendrimer which is non-toxic in the amount administered, the improvement wherein (a) the joint exhibits the symptoms of a degenerative joint disease or trauma; (b) the nitroxide is a bio-reductive resistant, positively charged at physiological pH, nitroxyl poly-functionalized dendrimer of Formula (I): wherein each R independently is either (A) a nitroxyl group of Formula (II): wherein X is an oxygen atom or two hydrogen atoms, n is the integer 0 or 2, R′ is lower alkyl and R″ is H or lower alkyl, or (B) a group of Formula (IV): wherein each alkylene in Formulae (I), and (IV) is a bridging divalent alkylene group of 2-6 carbon atoms with 2-3 carbon atoms in the chain and R is as defined herein; (c) wherein, for a given R of Formula I, the number of iterations of Formula IV is 0-4, (d) the number of terminal R groups in the dendrimer molecule which are nitroxyl groups of Formula (II) is from 12 to 48; and (e) the dose of the composition which is injected into the joint of such an animal is effective to selectively visualize the proteoglycans of the cartilage present in the joint in the MR image produced by the scan.