Claims for Patent: 5,573,748

Summary for Patent: 5,573,748

Title:	Radiolabeled technetium chelates for use in renal function determinations
Abstract:	The present invention is directed to novel radiopharmaceutical imaging agents incorporating Tc-99m as a radiolabel. In particular, the novel imaging agents disclosed herein have relatively high renal extraction efficiencies, and hence are useful for conducting renal function imaging procedures. The novel Tc-99m compounds of a present invention have the following general formula: ##STR1## wherein X is S or N; and wherein Y is H or wherein Y is ##STR2## and where R.sub.1 is --H, --CH.sub.3, or --CH.sub.2 CH.sub.3 ; R.sub.2 is --H, --CH.sub.2 CO.sub.2 H, --CH.sub.2 CONH.sub.2, --CH.sub.2 CH.sub.2 CO.sub.2 H, --CH.sub.2 CH.sub.2 CONH.sub.2, --CH.sub.3, --CH.sub.2 CH.sub.3, CH.sub.2 C.sub.6 H.sub.5, or --CH.sub.2 OH; and Z is --H, --CO.sub.2 H, --CONH.sub.2, --SO.sub.3 H, --SO.sub.2 NH.sub.2, or --CONHCH.sub.2 CO.sub.2 H; and the Tc is Tc-99m; and water-soluble salts thereof. Of the foregoing, the presently preferred Tc-99m compound of the present invention is Tc-99m-mercaptoacetylglycylglycylglycine (Tc-99m-MAGGG). The present invention is also directed to novel chelating agents that may be reacted with Tc-99m to form the foregoing compounds. Such novel chelating agents have the following general formula. ##STR3## where X and Y have the same definitions as above, and wherein Y' is --H.sub.2 when X is N, or wherein Y' is --H, or a suitable protective group such as --COCH.sub.3, --COC.sub.6 H.sub.5, --CH.sub.2 NHCOCH.sub.3, --COCF.sub.3, or --COCH.sub.2 OH when X is S. The present invention also provides methods for preparing and using the novel Tc-99m compounds.
Inventor(s):	Fritzberg; Alan (Edmonds, WA)
Assignee:	University of Utah Research Foundation (Salt Lake City, UT)
Application Number:	08/262,947
Patent Claims:	1. A prepackaged kit for use in preparing a compound comprising technetium-99m, said compound having the general formula ##STR18## and water-soluble salts thereof, said prepackaged kit comprising: A container containing a selected quantity of a ligand of the general formula ##STR19## wherein X is S or N; and wherein Y.sup.1 is --H or a group which protects the sulfur from oxidation where X is S, or wherein Y.sup.1 is --H.sub.2 where X is N; and wherein Y is --H or wherein Y is ##STR20## and where R.sub.1 is --H, --CH.sub.3, or --CH.sub.2 CH.sub.3 ; R.sub.2 is --H, --CH.sub.2 CO.sub.2 H, --CH.sub.2 CONH.sub.2, --CH.sub.2 CH.sub.2 CO.sub.2 H, --CH.sub.2 CH.sub.2 CONH.sub.2, --CH.sub.3, --CH.sub.2 CH.sub.3, or --CH.sub.2 OH; and Z is --H, --CO.sub.2 H, --CONH.sub.2, --SO.sub.3 H, --SO.sub.2 NH.sub.2, or --CONHCH.sub.2 CO.sub.2 H; a suitable amount of a water soluble stannous salt to induce the reaction of said ligand with a technetium-99m pertechnetate salt; and a suitable amount of an intermediate exchange ligand to complex with said suitable amount of soluble stannous salt, wherein said container has sufficient volume for accepting a suitable amount of a water soluble technetium-99m pertechnetate salt to provide a desired level of radioactivity. 2. A prepackaged kit as defined in claim 1, wherein X is S. 3. A prepackaged kit as defined in claim 2, wherein, when Y.sup.1 comprises said group which protects the sulfur from oxidation, Y.sup.1 is --COCH.sub.3, --COC.sub.6 H.sub.5, --CH.sub.2 NHCOCH.sub.3, --COCF.sub.3, --COCH.sub.2 CO.sub.2 H, or --COCH.sub.2 OH. 4. A prepackaged kit as defined in claim 2, wherein Y' is --COC.sub.6 H.sub.5, and Y is --CH.sub.2 CO.sub.2 H. 5. A prepackaged kit as defined in claim 2, wherein Y is --CHCH.sub.3 CO.sub.2 H; --CH(CH.sub.2 CONH.sub.2)CO.sub.2 H; or --CH(CH.sub.2 CH.sub.2 CONH.sub.2)COOH. 6. A prepackaged kit as defined in claim 2, wherein the intermediate exchange ligand is acetate, glycine, citrate, malonate, gluconate, tartrate, malate, lactate, hydroxyisobutyrate, pyrophosphate, N-methyl N,N'-bis(2hydroxyethyl)ethylenediamine, or glucoheptonate.