NOVEL ANTIBACTERIAL COMPOUNDS

Abstract: Novel multibinding compounds are disclosed. The compounds of the invention comprise from 2-10 ligands covalently connected, each of said ligands being capable of inhibiting bacterial Type II DNA topoisomerase, thereby modulating the biological processes/functions thereof.

Description: NOVEL ANTIBACTERIAL COMPOUNDS Cross Reference to Related Applications This application claims the benefit of United States Provisional Application Serial Numbers 60/088,448, filed June 8, 1998, and 60/093,072, filed July 16, 1998, both of which are incorporated by reference in their entirety. Field of the Invention This invention relates to novel therapeutic compounds that act as antibacterial agents by virtue of their ability to inhibit bacterial type II DNA topoisomerases, thus preventing replication of the bacteria. More particularly, the invention relates to novel antibacterial compounds that inhibit bacterial type II DNA topoisomerases by acting as multibinding agents. The multibinding agents of the invention comprise from 2-10 ligands covalently connected by a linker or linkers, wherein said ligands in their monovalent (i.e. unlinked) state are capable of inhibiting bacterial type II DNA topoisomerases. The manner in wh' h the ligands are linked is such that the multibinding agents so constructed demonstrate an increased biological and/or therapeutic effect as compared to the same number of unlinked ligands available for inhibiting bacterial type II DNA topoisomerases . The compounds of the invention are particularly useful in mammals for treating disease states that are mediated by bacteria. Accordingly, the invention also relates to pharmaceutical compositions comprising a pharmaceutically acceptable excipient and an effective amount of a compound of the invention, and to methods of using such compounds and pharmaceutical compositions containing them for the treatment of such conditions. The compounds are also useful for use in animal feed to improve the growth of livestock. Still further, the invention relates to methods of preparing such compounds. Background Antibacterial compounds that act by the inhibiting the action of bacterial type II DNA topoisomerases are well known. However, an increasing problem with respect to the effectiveness of such antibacterial agents relates to the emergence of strains of bacteria that are highly resistant to these agents. If no appropriate treatment is found, such strains will represent a significant health hazard. Additionally, existing antibacterial drugs have many disadvantages, including lack of selectivity for their target, low potency, short duration of action, toxicity, and the like. It would therefore be highly desirable to find antibacterial agents that are active against a broad spectrum of bacteria, in particular bacteria that are resistant to existing drug therapy. It would be also be advantageous to discover antibacterial agents that demonstrate high activity and selectivity toward their targets, and are of low toxicity. Related Disclosures Antibacterial compounds are disclosed in Patent Applications EP 0 802 199, EP 0 801 075, EP 0 667 353, WO 97/28812, U.S. 3,590,036, and in Biochemistry, 1989, 28, p3886-3894, Yakhak Hoeji, V38, No6, (1994), JACS H8, pp 13107-13108 (1996), JACS 119, pp 12041-12047 (1997), and JACS 116, pp 4573-4590 (1994). A method of reducing hair growth with DNA topoisomerase inhibitors is disclosed in WO 98/29086. The disclosures of these and other documents referred to throughout this application are incoφorated herein by reference. Summary of the Invention This invention addresses the above needs by providing novel multibinding agents. Accordingly, in one aspect, the present invention relates to novel multibinding agents: wherein a multibinding agent comprises 2-10 ligands, which may be the same or different, covalently connected by a linker or linkers, which may be the same or different, wherein each of said ligands is capable of inhibiting bacterial type II DNA topoisomerases. The preferred multibinding agents are represented by Formula I: (L)p(X)q Formula I in which L is a ligand that may be the same or different at each occurrence; X is a linker that may be the same or different at each occurrence; p is an integer of 2-10; and q is an integer of 1-20; or a salt thereof; wherein each of said ligands is capable of inhibiting bacterial type II DNA topoisomerases. Preferably q is less than p. In a second aspect, the invention relates to a method of treatment of mammals having a disease state that is treatable by a broad spectrum antibacterial, comprising administering a therapeutically effective amount of a novel multibinding agent thereto; wherein a multibinding agent comprises 2-10 ligands, which may be the same or different, covalently connected by a linker or linkers, which may be the same or different, wherein each of said ligands is capable of inhibiting bacterial type II DNA topoisomerases. The preferred multibinding agent is a compound of Formula I. In a third aspect, the invention relates to a pharmaceutical composition comprising a therapeutically effective amount of one or more multibinding agents, or a pharmaceutically acceptable salt thereof, said multibinding agent comprising 2-10 ligands, which may be the same or different, covalently connected by a linker or linkers, which may be the same or different, wherein each of said ligands is capable of inhibiting bacterial type II DNA topoisomerases, admixed with at least one pharmaceutically acceptable excipient. In a fourth aspect, the invention relates to processes for preparing the multibinding agents, in particular the compounds of Formula I. In a fifth aspect, the invention relates to a method of improving the growth of livestock. In a sixth aspect, the invention relates to a method for identifying a multibinding agent capable of inhibiting bacterial type II DNA topoisomerases, comprising preparing an array of multimeric agents, contacting the multimeric agent array with a bacterial type I DNA topoisomerase, and selecting a multibinding agent based upon its ability to bind o the 5-HT receptor. DETAILED DESCRIPTION OF THE INVENTION Bacterial type II DNA topoisomerases are enzymes that are essential for DNA replication and transcription in bacteria. Consequently, bacterial type II DNA topoisomerases are targets of chemotherapeutics designed to have antibacterial activity. The inhibition of two bacterial type II DNA topoisomerases, DNA Gyrase and DNA topoisomerase IV has been the focus of antimicrobial chemotherapeutics. DNA Gyrase (M r 373,560) is an enzyme that effects ATP-dependent relaxation of the DNA molecule, and catalyzes supercoiling. DNA topoisomerase IV is also an enzyme effecting ATP-dependent relaxation of the DNA molecule. It, however, does not catalyze DNA supercoiling. Antibacterial compounds that exert their antibacterial activity by the inhibition of bacterial type II DNA topoisomerases are well known. The exact mode of action of these compounds, whose effects are bactericidal, are unclear. However, it is understood that the activity of such compounds arises in some manner from the binding of the compound to bacterial DNA, or a bacterial type II DNA topoisomerase and/or to a bacterial type II DNA topoisomerase /DNA complex. Without wishing to be bound by theory or any particular mechanism of action, it is believed that the bacteria are killed as a result of the physiological effects of inhibitors of bacterial type II DNA topoisomerases, including filamentation, and loss of septation; inhibition of nucleoid segregation; vacuole formation, inhibition of DNA synthesis; inhibition of transcription and protein synthesis; loss of supercoiling; DNA damage; and increased mutation rate. Other effects include inhibition of conjugation, plasmid loss, and inhibition of virulence gene expression. Inhibition of DNA synthesis is probably the most important effect that the bacterial Type II DNA topoisomerase inhibitors exert on bacteria. The compounds of the invention are multibinding agents, and although not wishing to be bound or restricted by any particular theory or proposed mechanism of action, it is believed that the surprising activity of these compounds at least in part arises from their ability to bind to their target in a multivalent manner and inhibit bacterial type II DNA topoisomerases. In this manner, the energetic costs of binding to its target are lowered. Multivalent binding interactions are characterized by the concurrent interaction of at least two ligands of a multibinding agent with multiple ligand binding sites. Multivalent interactions differ from collections of individual monovalent interactions by the phenomenon of energetic coupling, wherein the binding of one ligand of a multibinding agent to its receptor will typically affect the thermodynamics of binding of a second ligand of the same multibinding agent, giving rise to an enhanced biological effect. The multivalent interactions may also circumvent resistance mechanisms exerted by recalcitrant bacterial strains. In some modes of resistance the monomeric compound has reduced affinity and is inhibitory against mutated forms of the bacterial topoisomerase. Multivalent ligands bind efficiently to the mutant topoisomerases because of the reduced energetics of the interaction. Definitions As used herein: The term "alkyl" refers to a monoradical branched or unbranched saturated hydrocarbon chain, preferably having from 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, secondary butyl, tert-butyl, n-hexyl, n-octyl, n-decyl, n- dodecyl, 2-ethyldodecyl, tetradecyl, and the like, unless otherwise indicated. The term "substituted alkyl" refers to an alkyl group as defined above having from 1 to 5 substituents selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, -SO-heteroaryl, -SO 2 - alkyl, -S0 -aryl, -S0 -heteroaryl, and mono- and di-alkylamino, mono- and di- cycloalkylamino, mono- and di-substituted cycloalkylamino, mono- and di-alkenylamino, mono- and di-substituted alkenylamino, mono- and di-cycloalkenylamino, mono- and di- substituted cycloalkenylamino, mono- and di-alkynylamino, mono- and di-substituted alkynylamino, mono- and di-arylamino, mono- and di-heteroarylamino, mono- and di- heterocyclic amino, and unsymmetric di-substituted amines having different substituents selected from alkyl, cycloalkyl, substituted cycloalkyl. alkenyl, substituted alkenyl, cycloalkenyl, substituted cycloalkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl and heterocyclic. The term "alkylene" refers to a diradical of a branched or unbranched saturated hydrocarbon chain, preferably having from 1 to 40 carbon atoms, preferably 1-10 carbon atoms, more preferably 1-6 carbon atoms. This term is exemplified by groups such as methylene (-CH 2 -), ethylene (-CH 2 CH -), the propylene isomers (e.g., -CH CH CH 2 - and - CH(CH 3 )CH 2 -) and the like. The term "substituted alkylene" refers to: (a) an alkylene group as defined above having from 1 to 5 substituents selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino (including, for example, N- glucosaminecarbonyl, benzoylamino, biphenylcarbonylamino, and the like), acyloxy, amino, aminoacyl, aminoacyloxy, oxyacylamino, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, thioaryloxy, heteroaryl, heteroaryloxy, thioheteroaryloxy, heterocyclic, heterocyclooxy, thioheterocyclooxy, nitro, and -NR a R , wherein R a and R b may be the same or different and are chosen from hydrogen, optionally substituted alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, heteroaryl and heterocyclic. Additionally, such substituted alkylene groups include those where 2 substituents on the alkylene group are fused to form one or more cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, heterocyclic or heteroaryl groups fused to the alkylene group, (b) an alkylene group as defined above that is interrupted by 1 -20 atoms or substituents independently chosen from oxygen, sulfur and NR a -, wherein R a is chosen from hydrogen, optionally substituted alkyl, cycloalkyl. alkenyl, cycloalkenyl, alkynyl, aryl, heteroaryl and heterocyclic; or (c) an alkylene group as defined above that has both from 1 to 5 substituents as defined above and is also interrupted by 1 -20 atoms as defined above. Examples of substituted alkylenes are chloromethylene (-CH(Cl)-), aminoethylene (-CH(NH 2 )CH 2 -), l-(dodecanoylamino)propylene (-CH[NHC(O)-(CH 2 )n-CH 3 ] CH 2 -), l-(4-phenylbenzoylamino)pentylene (-CH[NHC(0)-Z] (CH 2 ) ) ,2-carboxypropylene isomers (-CH 2 CH(CO 2 H)CH 2 -), ethoxyethyl (-CH 2 CH 2 O-CH 2 CH 2 -), -), ethylmethylaminoethyl (-CH 2 CH 2 N(CH 3 ) CH 2 CH 2 -), l-ethoxy-2-(2-ethoxy- ethoxy)ethane (-CH 2 CH 2 O-CH 2 CH 2 -O-CH 2 CH 2 0-CH 2 CH 2 -), and the like. The term "alkaryl" or "aralkyl" refers to the groups -alkylene-aryl and -substituted alkylene-aryl in which alkylene and aryl are as defined herein. Such alkaryl groups are exemplified by benzyl, phenethyl and the like. The term "alkoxy" refers to the groups alkyl-O-, alkenyl-O-, cycloalkyl-O-, cycloalkenyl-O-, and alkynyl-O-, where alkyl, alkenyl, cycloalkyl, cycloalkenyl, and alkynyl are as defined herein. Preferred alkoxy groups are alkyl-O- and include, by way of example, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n-hexoxy, 1 ,2-dimethylbutoxy, and the like The term "substituted alkoxy" refers to the groups substituted alkyl-O-, substituted alkenyl-O-, substituted cycloalkyl-O-, substituted cycloalkenyl-O-, and substituted alkynyl-O- where substituted alkyl, substituted alkenyl, substituted cycloalkyl, substituted cycloalkenyl and substituted alkynyl are as defined herein. The term "alkylalkoxy" refers to the groups -alkylene-O-alkyl, alkylene-O-substituted alkyl, substituted alkylene-O-alkyl and substituted alkylene-O- substituted alkyl wherein alkyl, substituted alkyl, alkylene and substituted alkylene are as defined herein. Examples of such groups are methylenemethoxy (-CH 2 OCH 3 ), ethylenemethoxy (-CH 2 CH OCH 3 ), n-propylene-iso-propoxy (-CH 2 CH 2 CH 2 OCH(CH 3 ) 2 ), methylene-t-butoxy (-CH 2 -0-C(CH 3 ) 3 ) and the like. The term "alkylthioalkoxy" refers to the group -alkylene-S-alkyl, alkylene-S-substituted alkyl, substituted alkylene-S-alkyl and substituted alkylene-S- substituted alkyl wherein alkyl, substituted alkyl, alkylene and substituted alkylene are as defined herein. Preferred alkylthioalkoxy groups are alkylene-S-alkyl and include, by way of example, methylenethiomethoxy (-CH 2 SCH 3 ), ethylenethiomethoxy (- CH 2 CH 2 SCH 3 ), n-propylene-iso-thiopropoxy (-CH 2 CH 2 CH 2 SCH(CH 3 ) 2 ), methylene-t- thiobutoxy (-CH 2 SC(CH 3 ) 3 ) and the like. "Alkenyl" refers to a monoradical of a branched or unbranched unsaturated hydrocarbon preferably having two to twenty carbon atoms, and preferably having 1 -6 double bonds. This term is further exemplified by such radicals as vinyl, prop-2-enyl, pent-3-enyl, hex-5-enyl, 5-ethyldodec-3,6-dienyl, and the like. The term "substituted alkenyl" refers to an alkenyl group as defined above having from 1 to 5 substituents selected from the group consisting of alkoxy, substituted alkoxy, acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thiol, thioalkoxy, substituted thioalkoxy, aryl, heteroaryl, heterocyclic, aryloxy, thioaryloxy, heteroaryloxy, thioheteroaryloxy, heterocyclooxy, thioheterocyclooxy, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, -SO-heteroaryl, -SO 2 -alkyl, -S0 2 -substituted alkyl, -S0 2 -aryl, -SO 2 - heteroaryl, and mono- and di-alkylamino, mono- and di-(substituted alkyl)amino, mono- and di-cycloalkylamino, mono- and di-substituted cycloalkylamino, mono- and di- alkenylamino, mono- and di-cycloalkenylamino, mono- and di-substituted cycloalkenylamino, mono- and di-alkynylamino, mono- and di-substituted alkynylamino, mono- and di-arylamino, mono- and di-heteroarylamino, mono- and di- heterocyclic amino, and unsymmetric di-substituted amines having different substituents selected from alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl and heterocyclic. "Alkenylene" refers to a diradical of an unsaturated hydrocarbon, preferably having two to twenty carbon atoms and preferably having 1-6 double bonds. This term is further exemplified by such radicals as 1,2-ethenyl, 1 ,3-prop-2-enyl, l,5-pent-3-enyl, 1,4- hex-5-enyl, 5-ethyl-l,12-dodec-3,6-dienyl, and the like. The term "substituted alkenylene" refers to an alkenylene group as defined above having from 1 to 5 substituents, selected from the group consisting of alkoxy, substituted alkoxy, acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, oxyacylamino, azido, cyano. halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, thioaryloxy, heteroaryl, heteroaryloxy, thioheteroaryloxy, heterocyclic, heterocyclooxy, thioheterocyclooxy, nitro, and mono- and di-alkylamino, mono- and di-(substituted alkyl)amino, mono- and di- cycloalkylamino, mono- and di-substituted cycloalkylamino, mono- and di-alkenylamino, mono- and di-substituted alkenylamino, mono- and di-cycloalkenylamino, mono- and di- substituted cycloalkenylamino, mono- and di-alkynylamino, mono- and di-substituted alkynylamino, mono- and di-arylamino, mono- and di-heteroarylamino, mono- and di- heterocyclic amino, and unsymmetric di-substituted amines having different substituents selected from alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, substituted alkenyl, cycloalkenyl, substituted cycloalkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl and heterocyclic. Additionally, such substituted alkenylene groups include those where 2 substituents on the alkenylene group are fused to form one or more cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, heterocyclic or heteroaryl groups fused to the alkenylene group. "Alkynyl" refers to a monoradical of an unsaturated hydrocarbon, preferably having two to twenty carbon atoms, and preferably having 1-6 triple bonds. This term is further exemplified by such radicals as acetylenyl, prop-2-ynyl, pent-3-ynyl, hex-5-ynyl, 5-ethyldodec-3,6-diynyl, and the like. The term "substituted alkynyl" refers to an alkynyl group as defined above having from 1 to 5 substituents, selected from the group consisting of alkoxy, substituted alkoxy, acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, oxyacylamino, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, thioaryloxy, heteroaryl, heteroaryloxy, thioheteroaryloxy, heterocyclic, heterocyclooxy, thioheterocycloxy, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, -SO-heteroaryl, -SO 2 -alkyl, -SO 2 -substituted alkyl, -SO 2 -aryl, -SO -heteroaryl, SO2-heterocyclic, mono- and di-alkylamino, mono- and di-(substituted alkyl)amino, mono- and di-cycloalkylamino, mono- and di-substituted cycloalkylamino, mono- and di-alkenylamino, mono- and di-substituted alkenylamino, mono- and di- cycloalkenylamino, mono- and di-substituted cycloalkenylamino, mono- and di- alkynylamino, mono- and di-substituted alkynylamino, mono- and di-arylamino, mono- and di-heteroarylamino, mono- and di-heterocyclic amino, and unsymmetric di- substituted amines having different substituents selected from alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, substituted alkenyl, cycloalkenyl, substituted cycloalkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl and heterocyclic. "Alkynylene" refers to a diradical of an unsaturated hydrocarbon radical, preferably having two to twenty carbon atoms, and preferably having 1-6 triple bonds. This term is further exemplified by such radicals as l,3-prop-2-ynyl, l,5-pent-3-ynyl, 1,4- hex-5-ynyl, 5-ethyl-l,12-dodec-3,6-diynyl, and the like. The term "acyl" refers to the groups alkyl-C(O)-, substituted alkyl-C(O)-, cycloalkyl-C(O)-, substituted cycloalkyl-C(O)-, cycloalkenyl-C(O)-, substituted cycloalkenyl-C(O)-, aryl-C(O)-, heteroaryl-C(O)- and heterocyclic-C(O)- where alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, heteroaryl and heterocyclic are as defined herein. The term "acylamino" refers to the group -C(0)NRR where each R is independently hydrogen, alkyl, substituted alkyl, aryl, heteroaryl, heterocyclic or where both R groups are joined to form a heterocyclic group (e.g., morpholino) wherein alkyl, substituted alkyl, aryl, heteroaryl and heterocyclic are as defined herein. The term "aminoacyl" refers to the group -NRC(O)R where each R is independently hydrogen, alkyl, substituted alkyl, aryl, heteroaryl, or heterocyclic wherein alkyl, substituted alkyl, aryl, heteroaryl and heterocyclic are as defined herein. The term "aminoacyloxy" refers to the group -NRC(O)OR where each R is independently hydrogen, alkyl, substituted alkyl, aryl, heteroaryl, or heterocyclic wherein alkyl, substituted alkyl, aryl, heteroaryl and heterocyclic are as defined herein. The term "acyloxy" refers to the groups alkyl-C(O)O-, substituted alkyl-C(O)O-, cycloalkyl-C(0)0-, substituted cycloalkyl-C(O)O-, aryl-C(O)O-, heteroaryl-C(O)O-, and heterocyclic-C(0)0- wherein alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl, heteroaryl, and heterocyclic are as defined herein. The term "aryl" refers to an unsaturated aromatic carbocyclic group of from 6 to 14 carbon atoms having a single ring (e.g., phenyl) or multiple condensed (fused) rings (e.g., naphthyl or anthryl). Unless otherwise constrained by the definition for the aryl substituent, such aryl groups can optionally be substituted with from 1 to 5 substituents selected from the group consisting of acyloxy, hydroxy, thiol, acyl, alkyl, alkoxy, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, substituted alkyl, substituted alkoxy, substituted alkenyl, substituted alkynyl, substituted cycloalkyl, substituted cycloalkenyl, amino, aminoacyl, acylamino, alkaryl, aryl, aryloxy, azido, carboxyl, carboxylalkyl, cyano, halo, nitro, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, aminoacyloxy, oxyacylamino, thioalkoxy, substituted thioalkoxy, thioaryloxy, thioheteroaryloxy, -SO-alkyl, -SO- substituted alkyl, -SO-aryl, -SO-heteroaryl, -S0 2 -alkyl, -S0 2 -substituted alkyl, -S0 2 -aryl, -S0 2 -heteroaryl, trihalomethyl, mono-and di-alkylamino, mono- and di-(substituted alkyl)amino, mono- and di-cycloalkylamino, mono- and di-substituted cycloalkylamino, mono- and di-alkenylamino, mono- and di-substituted alkenylamino, mono- and di- cycloalkenylamino, mono- and di-substituted cycloalkenylamino, mono- and di- alkynylamino, mono- and di-substituted alkynylamino, mono- and di-arylamino, mono- and di-heteroarylamino, mono- and di-heterocyclic amino, and unsymmetric di- substituted amines having different substituents selected from alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, substituted alkenyl, cycloalkenyl, substituted cycloalkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl, heterocyclic and the like. Preferred aryl substituents include alkyl, alkoxy, halo, cyano, nitro, trihalomethyl, and thioalkoxy. The term "aryloxy" refers to the group aryl-O- wherein the aryl group is as defined above including optionally substituted aryl groups as also defined above. The term "arylene" refers to a diradical derived from aryl or substituted aryl as defined above, and is exemplified by 1,2-phenylene, 1,3-phenylene, 1 ,4-phenylene, 1,2- naphthylene and the like. The term "carboxyalkyl" refers to the group "-C(O)Oalkyl" where alkyl is as defined above. The term "cycloalkyl" refers to cyclic alkyl groups of from 3 to 20 carbon atoms having a single cyclic ring or multiple condensed rings. Such cycloalkyl groups include, by way of example, single ring structures such as cyclopropyl, cyclobutyl, cyclopentyl, cyclooctyl, and the like, or multiple ring structures such as adamantanyl, and the like. The term "substituted cycloalkyl" refers to cycloalkyl groups having from 1 to 5 substituents selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO- substituted alkyl, -SO-aryl, -SO-heteroaryl, -S0 2 -alkyl, -S0 2 -substituted alkyl, -SO -aryl, -S0 -heteroaryl, and mono- and di-alkylamino, mono- and di-(substituted alkyl)amino, mono- and di-cycloalkylamino, mono- and di-alkenylamino, mono- and di-substituted alkenylamino, mono- and di-cycloalkenylamino, mono- and di-substituted cycloalkenylamino. mono- and di-alkynylamino, mono- and di-substituted alkynylamino, mono- and di-arylamino, mono- and di-heteroarylamino, mono- and di- heterocyclic amino, and unsymmetric di-substituted amines having different substituents selected from alkyl, substituted alkyl, cycloalkyl, alkenyl, substituted alkenyl, cycloalkenyl, substituted cycloalkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl and heterocyclic. The term "cycloalkenyl" refers to cyclic alkenyl groups of from 4 to 8 carbon atoms having a single cyclic ring and at least one point of internal unsaturation. Examples of suitable cycloalkenyl groups include, for instance, cyclobut-2-enyl, cyclopent-3-enyl. cyclooct-3-enyl and the like. The term "substituted cycloalkenyl" refers to cycloalkenyl groups having from 1 to 5 substituents selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy. thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl. heteroaryloxy, heterocyclic, heterocyclooxy. hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, -SO-heteroaryl, -S0 2 - alkyl, -SO?-substituted alkyl, -S0 2 -aryl, -S0 -heteroaryl, and mono- and di-alkylamino, mono- and di-(substituted alkyl)amino, mono- and di-cycloalkylamino, mono- and di- substituted cycloalkylamino, mono- and di-alkenylamino, mono- and di-substituted alkenylamino, mono- and di-cyc alkenylamino, nτ~>no- and di-substituted cycloalkenylamino, mono- and di-alkynylamino, mono- and di-substituted alkynylamino, mono- and di-arylamino, mono- and di-heteroarylamino, mono- and di- heterocyclic amino, and unsymmetric di-substituted amines having different substituents selected from alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, substituted alkenyl, cycloalkenyl, substituted cycloalkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl and heterocyclic. The term "halo" or "halogen" refers to fluoro, chloro, bromo and iodo. "Haloalkyl" refers to alkyl as defined above substituted by 1 -4 halo groups as defined above, which may be the same or different, such as 3-fluorododecyl, 12,12,12- trifluorododecyl, 2-bromooctyl, -3-bromo-6-chloroheptyl, and the like. The term "heteroaryl" refers to an aromatic carbocyclic group of from 1 to 15 carbon atoms and 1 to 4 heteroatoms selected from oxygen, nitrogen and sulfur within at least one ring (if there is more than one ring). Unless otherwise constrained by the definition for the heteroaryl substituent, such heteroaryl groups can be optionally substituted with 1 to 5 substituents selected from the group consisting of acyloxy, hydroxy, thiol, acyl, alkyl, alkoxy, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, substituted alkyl, substituted alkoxy, substituted alkenyl, substituted alkynyl, substituted cycloalkyl, substituted cycloalkenyl, amino, aminoacyl, acylamino, alkaryl, aryl, aryloxy, azido, carboxyl, carboxylalkyl, cyano, halo, nitro, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, aminoacyloxy, oxyacylamino, thioalkoxy, substituted thioalkoxy, thioaryloxy, thioheteroaryloxy, -SO-alkyl, -SO- substituted alkyl, -SO-aryl, -SO-heteroaryl, -S0 2 -alkyl, -S0 2 -substituted alkyl, -S0 -aryl, -S0 -heteroaryl, trihalomethyl, mono-and di-alkylamino, mono- and di-(substituted alkyl)amino, mono- and di-cycloalkylamino, mono- and di-substituted cycloalkylamino, mono- and di-alkenylamino, mono- and di-substituted alkenylamino, mono- and di- cycloalkenylamino, mono- and di-substituted cycloalkenylamino, mono- and di- alkynylamino, mono- and di-substituted alkynylamino, mono- and di-arylamino, mono- and di-heteroarylamino, mono- and di-heterocyclic amino, and unsymmetric di- substituted amines having different substituents selected from alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, substituted alkenyl, cycloalkenyl, substituted cycloalkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl, heterocyclic and the like. Preferred aryl substituents include alkyl. alkoxy. halo, cyano, nitro, trihalomethyl, and thioalkoxy. Such heteroaryl groups can have a single ring (e.g., pyridyl or furyl) or multiple condensed rings (e.g., indolizinyl or benzothienyl). Preferred heteroaryls include pyridyl, pyrrolyl and furyl. The term "heteroaryloxy" refers to the group heteroaryl-O-. The term "heteroarylene" refers to the diradical group derived from heteroaryl or substituted heteroaryl as defined above, and is exemplified by the groups 2,6-pyridylene, 2,4-pyridiylene, 1 ,2-quinolinylene, 1,8-quinolinylene, 1 ,4-benzofuranylene, 2,5- pyridinylene, 1,3-morpholinylene, 2,5-indolenyl, and the like. The term "heterocycle" or "heterocyclic" or "heterocyclo" refers to a monoradical saturated or unsaturated group having a single ring or multiple condensed rings, from 1 to 40 carbon atoms and from 1 to 10 hetero atoms, preferably 1 to 4 heteroatoms, selected from nitrogen, sulfur, phosphorus, and/or oxygen within the ring. Unless otherwise constrained by the definition for the heterocyclic substituent, such heterocyclic groups can be optionally substituted with 1 to 5, and preferably 1 to 3 substituents, selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, oxyaminoacyl, cyano, halogen, hydroxyl, keto, thioketo, carboxyl. carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy. substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO- substituted alkyl, -SO-aryl, -SO-heteroaryl, -S0 2 -alkyl, -S0 2 -substituted alkyl, -S0 2 -aryl, -S0 2 -heteroaryl, and mono- and di-alkylamino, mono- and di-(substituted alkyl)amino, mono- and di-cycloalkylamino, mono- and di-substituted cycloalkylamino, mono- and di- alkenylamino, mono- and di-substituted alkenylamino, mono- and di-cycloalkenylamino, mono- and di-substituted cycloalkenylamino, mono- and di-alkynylamino, mono- and di- substituted alkynylamino, mono- and di-arylamino, mono- and di-heteroarylamino, mono- and di-heterocyclic amino, and unsymmetric di-substituted amines having different substituents selected from alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, substituted alkenyl, cycloalkenyl, substituted cycloalkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl and heterocyclic. Such heterocyclic groups can have a single ring or multiple condensed rings. Examples of nitrogen heterocycles and heteroaryls include, but are not limited to, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole, indole. indazole, purine, quinolizine, isoquinoline, quinoline, phthalazine, naphthylpyridine, quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine, acridine, phenanthroline, isothiazole, phenazine, isoxazole, phenoxazine, phenothiazine, imidazolidine, imidazoline, piperidine, piperazine, indoline, morpholino, piperidinyl, tetrahydrofuranyl, and the like as well as N-alkoxy-nitrogen containing heterocycles. A preferred class of heterocyclics include "crown compounds" which refers to a specific class of heterocyclic compounds having one or more repeating units of the formula [-(CH 2 -) m Y-] where m is equal to or greater than 2, and Y at each separate occurrence can be O, N, S or P. Examples of crown compounds include, by way of example only, [-(CH 2 ) 3 -NH-] 3 , [-((CH 2 ) 2 -0) 4 -((CH 2 ) 2 -NH) 2 ] and the like. Typically such crown compounds can have from 4 to 10 heteroatoms and 8 to 40 carbon atoms. The term "heterocyclooxy" refers to the group heterocyclic-O-. The term "thioheterocyclooxy" refers to the group heterocyclic-S-. The term "heterocyclene" refers to the diradical group formed from a heterocycle as defined herein, and is exemplified by the groups 2,6-morpholino, 2,5-morpholino and the like. The term "oxyacylamino" refers to the group -OC(0)NRR where each R is independently hydrogen, alkyl, substituted alkyl, aryl, heteroaryl, or heterocyclic wherein alkyl, substituted alkyl, aryl, heteroaryl and heterocyclic are as defined herein. The term "thiol" refers to the group -SH. The term "thioalkoxy" refers to the group -S-alkyl. The term "substituted thioalkoxy" refers to the group -S-substituted alkyl. The term "thioaryloxy" refers to the group aryl-S- wherein the aryl group is as defined above including optionally substituted aryl groups also defined above. The term "thioheteroaryloxy" refers to the group heteroaryl-S- wherein the heteroaryl group is as defined above including optionally substituted aryl groups as also defined above. As to any of the above groups which contain one or more substituents, it is understood, of course, that such groups do not contain any substitution or substitution patterns which are sterically impractical and/or synthetically non-feasible. In addition, the compounds of this invention include all stereochemical isomers arising from the substitution of these compounds. "Alkyl optionally interrupted by 1-5 atoms chosen from O, S, or N" refers to alkyl as defined above in which the carbon chain is interrupted by O, S, or N. Within the scope are ethers, sulfides, and amines, for example 1-methoxydecyl, 1-pentyloxynonane, l-(2- isopropoxyethoxy)-4-methylnonane, l-(2-ethoxyethoxy)dodecyl, 2-(t-butoxy)heptyl, 1- pentylsulfanylnonane, nonylpentylamine, and the like. "Heteroarylalkyl" refers to heteroaryl as defined above linked to alkyl as defined above, for example pyrid-2-ylmethyl, 8-quinolinylpropyl, and the like. "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances in which it does not. "Ligand" as used herein denotes an antibacterial compound that impairs the viability of bacteria by inhibiting bacterial type II DNA topoisomerases. The ligand has a single ligand domain. As noted above, although it is known that a ligand exerts its activity by binding of the ligand to the target , that is bacterial DNA, or a bacterial Type II DNA topoisomerase, or to the topoisomerase/DNA complex, the exact mode of binding of such ligands is not clear. Accordingly, a ligand as used herein is considered to be a compound that is a binding partner for bacterial DNA, bacterial Type II DNA topoisomerase or the Type II DNA topoisomerase /DNA complex (its "receptor") and is bound thereto by complementarity. The specific region or regions of the ligand that is (are) recognized by the bacterial Type II DNA topoisomerase and/or the Type II DNA topoisomerase /DNA complex is designated as the "ligand domain". By virtue of the ligand domain, a ligand may be either capable of binding to bacterial DNA, bacterial Type II DNA topoisomerase or Type II DNA topoisomerase /DNA complex by itself, or may require the presence of one or more non-ligand components for binding (e.g. Ca 2+ , Mg 2+ , or a water molecule is required for the binding of a ligand domain to various receptors). A preferred class of ligands is the "quinolone" class. Examples of ligands useful in this invention, including quinolones, are shown as Formula II. Non-quinolone ligands include novobiocin, coumermycin Al, cinodine, microcin, clerocidin, cyclothialidine, and the like. Those skilled in the art will appreciate that portions of the ligand structure that are not essential for molecular recognition and binding activity (i.e. that are not part of the ligand domain) may be varied substantially, replaced or substituted with unrelated structures (for example, with ancillary groups as defined below), and, in some cases, omitted entirely without affecting the binding interaction. Accordingly, it should be understood that the term ligands is not intended to be limited to compounds known to be useful as antibacterial compounds (for example, known drugs). Those skilled in the art will understand that the term ligand can equally apply to a molecule that is not normally recognized as having useful properties related to binding to bacterial bacterial type II DNA topoisomerases (and thus inhibiting the enzyme), in that ligands that exhibit minimally useful properties as monomers can be highly active as multibinding agents, due to the biological benefit (increased biological effect) conferred by multivalency.. The primary requirement for a ligand as defined herein is that it has a ligand domain as defined above. It should be understood that the term "ligand" or "ligands" is intended to include racemic ligands as well as the individual stereoisomers of the ligands, including pure enantiomers and non-racemic mixtures thereof. Additionally, the term "linker" is intended to include racemic linkers as well as the individual stereoisomers of the linkers, including pure enantiomers and non-racemic mixtures thereof. The scope of the invention as described and claimed encompasses the racemic forms of the ligands and linkers as well as their individual enantiomers and non-racemic mixtures thereof, and accordingly includes all stereoisomers of the compounds of Formula I. Preferred ligands within the scope of this definition are quinolones of the formula: Formula II wherein: R , ι is hydrogen, lower alkyl, lower alkoxy, lower haloalkyl, cycloalkyl, cycloalkylalkyl, alkylamino. aryl, heteroaryl, or heterocyclo; R )2 ; is hydrogen, lower alkyl; lower alkoxy, or halo; R is -COOR , in which R is hydrogen or lower alkyl; or R and RR wwhheenn ttaakkeenn ttooggeetthher with the carbons to which they are attached represent a group of the formula; in which R is hydrogen or lower alkyl; R " is hydrogen, lower alkyl, lower alkoxy, hydroxy. halo, cycloalkyl, cycloalkylalkyl, amino, alkylamino. aryl, heteroaryl, or heterocyclo; Y is -N- or -CR 6 -. in which R 6 is hydrogen, lower alkyl, hydroxy, lower alkoxy, halo, cycloalkyl, cycloalkylalkyl, alkylamino, aryl, heteroaryl, or heterocyclo; R 7 is hydrogen, lower alkyl. lower alkoxy, hydroxy, halo, cycloalkyl, cycloalkylalkyl, alkylamino, aryl, heteroaryl, or heterocyclo; Z is -N- or -CR 8 -, in which R 8 is hydrogen, lower alkyl, or halo; or R and R when taken together represent a group of the formula 0-W-O; or R and R when taken together represent a group of the formula -O-W-; in which W is lower alkylene. The preferred points of attachment to a linker are at positions R 1 , R 2 , R 5 , R 6 , R 7 and R 8 . It should be noted that where R 7 is piperazin-1-yl, a more preferred point of attachment of the linker is to the 4 " -position of the piperazine group (i.e. the NH group). "Multibinding agent" or "multibinding compound" as used herein refers to a compound that is capable of multivalency as defined herein, and which has 2-10 ligands as defined herein, which may be the same or different, connected by one or more covalent linker or linkers, which may be the same or different, preferably from 1-20 in number. A multibinding agent provides an improved biological and/or therapeutic effect as measured against that achieved by the same number of unlinked ligands available for binding to the ligand binding site of the bacterial type II DNA topoisomerase and/or the type II DNA topoisomerase /DNA complex. Examples of increased biological and/or therapeutic effect with respect to the target include, for example, increased specificity, increased affinity, increased selectivity, increased potency, increased efficacy, increased therapeutic index, a change in the duration of action, decreased toxicity, decreased side effects, improved bioavailability, improved pharmacokinetics, improved activity spectrum, and the like. The multibinding compounds of the invention exhibit one or more of the foregoing effects. "Potency" as used herein refers to the minimum concentration at which a ligand is able to achieve a desirable biological or therapeutic effect. The potency of a ligand is typically proportional to its affinity for its ligand binding site. In some cases, the potency may be non-linearly correlated with its affinity. In comparing the potency of two drugs, e.g., a multibinding agent and the aggregate of its unlinked ligand, the dose- response curve of each is determined under identical test conditions (e.g., in an in vitro or in vivo assay or in an appropriate animal model. The finding that the multibinding agent produces an equivalent biological or therapeutic effect at a lower concentration than the aggregate unlinked ligand (e.g., on a per weight, per mole, or per ligand basis) is indicative of enhanced potency. "Univalency " as used herein refers to a single binding interaction between the ligand domain of one ligand as defined herein with the ligand recognition site of a bacterial Type II DNA topoisomerase and/or the Type II DNA topoisomerase /DNA complex. It should be noted that a compound having multiple copies of a ligand (or ligands) exhibits univalency when only one ligand of that compound is interacting with a ligand binding site. Examples of univalent interactions are depicted below. where the arrow represents a ligand domain and the indent represents the ligand binding site of a receptor (a Type II DNA topoisomerase or Type II DNA topoisomerase complex). "Multivalency" as used herein refers to the concurrent binding of 2 to 10 linked ligands (which may be the same or different) and two or more corresponding ligand binding sites of bacterial Type II DNA topoisomerase and/or the Type II DNA topoisomerase /DNA complex. Accordingly, two ligands connected by a linker that bind concurrently to two ligand binding sites are considered to be a bivalent compound; similarly, three ligands thus connected provide a trivalent compound. It should be understood that all compounds that contain multiple copies of a ligand attached to a linker (or linkers) do not necessarily exhibit the phenomena of multivalency, i.e. that improved biological and/or therapeutic effect of the multibinding agent is obtained as measured against that produced by the same number of unlinked ligands available for binding to a ligand binding site. For multivalency to occur, the ligand domains of the ligands that are connected by a linker have to be presented to their appropriate receptor(s) (i.e. the ligand binding sites) by the linker in a specific manner in order to bring about the desired ligand-orienting result, and thus produce a multibinding event. Thus, the term "multimeric ligand compound" refers to multiple copies of a ligand attached to a linker (or linkers) that may or may not exhibit the phenomena of multivalency. "Multimeric ligand compound library" refers to the collection of multimeric ligand compounds that are provided by the synthetic methods disclosed herein. "Selectivity" or "specificity" is a measure of the binding preferences of a ligand for different receptors and/or different ligands for the same receptor. The selectivity of a ligand with respect to its target receptor relative to another receptor is given by the ratio of the respective values of Kj (i.e., the dissociation constants for each ligand-receptor complex), or in cases where a biological effect is observed below the K_ selectivity is given by the ratio of the respective EC 50 s (i.e. the concentrations that produce 50% of the maximum response for the ligand interacting with the two distinct receptors). The term "ligand recognition site" or "ligand binding site" as used herein denotes the site on a bacterial Type II DNA topoisomerase and/or the Type II DNA topoisomerase /DNA complex that recognizes a ligand domain and provides a binding partner for a ligand. The ligand binding site may be defined by monomeric or multimeric structures. It should be recognized that the ligand binding sites that participate in biological multivalent binding interactions are constrained to varying degrees by their intra- and intermolecular associations (e.g., they may be covalently joined in a single or multiple structure, noncovalently associated in a multimeric structure, embedded in a membrane or polymeric matrix, and so on) and therefore have less relative translational and rotational freedom than if the same receptors were present as monomers in solution. The terms "agonism" and "antagonism" are well known in the art. By the term "modulatory effect" we mean the ability of a ligand to change the biological effect of an agonist or antagonist through binding to a receptor. As used herein, the terms "inert organic solvent" or "inert solvent" mean a solvent inert under the conditions of the reaction being described in conjunction therewith [including, for example, benzene, toluene, acetonitrile, tetrahydrofuran ("THF"), dimethylformamide ("DMF"), chloroform ("CHC1 3 "), methylene chloride (or dichloromethane or "CH 2 C1 2 "), diethyl ether, ethyl acetate, acetone, methyiethyl ketone, methanol, ethanol, propanol, isopropanol, tert-butanol, dioxane, pyridine, and the like]. Unless specified to the contrary, the solvents used in the reactions of the present invention are inert solvents. "Pharmaceutically acceptable salt" means those salts which retain the biological effectiveness and properties of the multivalent compounds of the invention, and which are not biologically or otherwise undesirable. The multivalent compounds of the invention are capable of forming both acid and base salts by virtue of the presence of amino and carboxyl groups respectively. 1. Pharmaceutically acceptable base addition salts may be prepared from inorganic and organic bases. Salts derived from inorganic bases include, but are not limited to, the sodium, potassium, lithium, ammonium, calcium, and magnesium salts. Salts derived from organic bases include, but are not limited to, salts of primary, secondary and tertiary amines, substituted amines including naturally-occurring substituted amines, and cyclic amines, including isopropylamine, trimethyl amine, diethylamine, triethylamine, tripropylamine, ethanolamine, 2-dimethylaminoethanol, tromethamine, lysine, arginine, histidine, caffeine, procaine, hydrabamine, choline, betaine, ethylenediamine, glucosamine, N-alkylglucamines, theobromine, purines, piperazine, piperidine, and N- ethylpiperidine. It should also be understood that other carboxylic acid derivatives would be useful in the practice of this invention, for example carboxylic acid amides, including carboxamides, lower alkyl carboxamides, di(lower alkyl) carboxamides, and the like. 2. Pharmaceutically acceptable acid addition salts may be prepared from inorganic and organic acids. Salts derived from inorganic acids include hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid and the like. Salts derived from organic acids include acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, malic acid, malonic acid, succinic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid and the like. The term "treatment" as used herein covers any treatment of a condition or disease in an animal, particularly a mammal, more particularly a human, and includes: (i) preventing the disease or condition from occurring in a subject which may be predisposed to the disease but has not yet been diagnosed as having it; (ii) inhibiting the disease or condition, i.e. arresting its development; (iii) relieving the disease or condition, i.e. causing regression of the condition; or. (iv) relieving the conditions caused by the disease, i.e. symptoms of the disease. The term "disease or condition which is alleviated by treatment with a multibinding agent" as used herein covers all conditions and disease states which are generally acknowledged in the art to be usefully treated with the ligands as defined in general, and those disease states which have been found to be usefully treated by the specific multibinding agents of our invention, including the compounds of Formula I. The term covers prophylactic treatment as well as relief or regression of the disease. Such disease states include, but are not limited to. treatment of a mammal for modifying physiological functions related to bacterial diseases, and the like. The term "therapeutically effective amount" refers to that amount of a multibinding agent, for example a compound of Formula I, that is sufficient to effect treatment, as defined above, when administered to a mammal or avian in need of such treatment. The therapeutically effective amount will vary depending on the subject and disease state being treated, the severity of the affliction and the manner of administration, and the like, and may be determined routinely by one of ordinary skill in the art. The term "protecting group" or "blocking group" refers to any group which when bound to one or more hydroxyl, thiol, amino or carboxyl groups of the compounds prevents reactions from occurring at these groups and which protecting group can be removed by conventional chemical or enzymatic steps to reestablish the hydroxyl, thio, amino or carboxyl group. The particular removable blocking group employed is not critical and preferred removable hydroxyl blocking groups include conventional substituents such as allyl, benzyl, acetyl, chloroacetyl, thiobenzyl, benzylidine, phenacyl, t-butyl-diphenylsilyl and any other group that can be introduced chemically onto a hydroxyl functionality and later selectively removed either by chemical or enzymatic methods in mild conditions compatible with the nature of the product. Protecting groups are disclosed in more detail in T.W. Greene and P.G.M. Wuts, "Protective Groups in Organic Synthesis" 2 nd Ed., 1991, John Wiley and Sons, N.Y. Preferred removable amino blocking groups include conventional substituents such as t-butyoxycarbonyl (t-BOC), benzyloxycarbonyl (CBZ), fluorenylmethoxycarbonyl (FMOC), allyloxycarbonyl (ALOC) and the like, which can be removed by conventional conditions compatible with the nature of the product. Preferred carboxyl protecting groups include esters such as methyl, ethyl, propyl, t-butyl etc. which can be removed by mild conditions compatible with the nature of the product. "Linker" or "linkers" as used herein, identified where appropriate by the symbol X, refers to a group or groups that covalently link(s) from 2-10 ligands (as defined herein) in a manner that provides a compound capable of multivalency. The linker is a ligand domain orienting entity that permits attachment of multiple copies of ligands (which may be the same or different) thereto. The extent to which multivalent binding is realized depends upon the efficiency with which the linker that joins the ligands permits the ligand domains to be presented to the ligand recognition sites. Beyond presenting ligand domains for multivalent interactions with receptors, the linker spatially constrains these interactions to occur within dimensions defined by the linker. Thus, the structural features of the linker (valency, geometry, orienting capabilities, size, flexibility, chemical composition) are features of multibinding agents that play an important role in determining their activities. The term linker, however, does not include solid inert supports such as beads, resins, glass particles, rods, fibers, and the like, but it should be understood that the multibinding compounds of the invention can be attached to a solid support if desired to provide, for example, a material useful for separation and purification processes (e.g. affinity chromatography). The ligands are covalently attached to the linker or linkers using conventional chemical techniques, for example reaction between a carboxylic acid and an amine to form an amide, an amine and a sulfonyl halide to form a sulfonamide, an alcohol or phenol with an alkyl or aryl halide to form an ether, and the like. The linker (or linkers) is attached to the ligand at a position such that the ligand domain is permitted to orient itself appropriately in order to bind to the ligand binding site. The term linker embraces everything that is not considered to be part of the ligand. The relative orientation in which the ligand domains are displayed derives from the particular point or points of attachment of the ligands to the linker, and on the framework geometry. The determination of where acceptable substitutions can be made on a ligand is typically based on prior knowledge of structure-activity relationships of the ligand and/or congeners and/or structural information about ligand-receptor complexes (e.g., from X-ray crystallography, NMR). Such positions and the synthetic methods for covalent attachment are well known in the art. Suitable linkers are discussed below. At present, it is preferred that the multibinding agent is a bivalent compound, in which two ligands are covalently linked. "Biological effect" as used herein includes, but is not limited to. increased affinity, increased selectivity, increased potency, increased efficacy, increased duration of action, decreased toxicity, and the like. Combinatorial Libraries The methods described above lend themselves to combinatorial approaches for selecting compounds that have multibinding properties related to the inhibition of bacterial type II DNA topoisomerases from a library of multimeric compounds. Specifically, factors such as the proper juxtaposition of the individual ligands of a multibinding compound with respect to the relevant array of binding sites on a target or targets is important in optimizing the interaction of the multibinding compound with its target(s) and to maximize the biological advantage through multivalency. One approach is to identify a library of candidate multibinding compounds with properties spanning the multibinding parameters that are relevant for a particular target. These parameters include: (1) the identity of ligand(s), (2) the orientation of ligands, (3) the valency of the construct, (4) linker length, (5) linker geometry, (6) linker physical properties, and (7) linker chemical functional groups. Libraries of multimeric compounds potentially possessing multibinding properties (i.e., candidate multibinding compounds) and comprising a multiplicity of such variables are prepared and these libraries are then evaluated via conventional assays corresponding to the ligand selected and the multibinding parameters desired. Considerations relevant to each of these variables are set forth below: Selection of ligand(s) A single ligand or set of ligands that are capable of inhibiting bacterial type II DNA topoisomerases is (are) selected for incorporation into the libraries of candidate multibinding compounds. The only requirement for the ligands chosen is that they are capable of interacting with a bacterial type II DNA topoisomerase(s). Thus, the chosen ligands may be known drugs, modified forms of known drugs, substructures of known drugs or substrates of modified forms of known drugs (which are competent to interact with the target), or other compounds. The ligands are preferably chosen based on known favorable properties that may be projected to be carried over to or amplified in multibinding forms. Favorable properties include demonstrated safety and efficacy in human patients, appropriate PK/ADME profiles, synthetic accessibility, and desirable physical properties such as solubility, logP, etc. However, it is crucial to note that ligands that display an unfavorable property from among the previous list may obtain a more favorable property through the process of multibinding compound formation; i.e., ligands should not necessarily be excluded on such a basis. For example, a ligand that is not sufficiently potent at a particular target so as to be efficacious in a human patient may become highly potent and efficacious when presented in multibinding form. A ligand that is potent and efficacious but not of utility because of a non-mechanism-related toxic side effect may have increased therapeutic index (increased potency relative to toxicity) as a multibinding compound. Compounds that exhibit short in vivo half-lives may have extended half-lives as multibinding compounds. Physical properties of ligands that limit their usefulness (e.g. poor bioavailability due to low solubility, hydrophobicity, hydrophilicity) may be rationally modulated in multibinding forms, providing compounds with physical properties consistent with the desired utility. Orientation: selection of ligand attachment points and linking chemistry Several points are chosen on each ligand at which to attach the ligand to the linker. The selected points on the ligand/linker for attachment are functionalized to contain complementary reactive functional groups. This permits probing the effects of presenting the 5-HT ligands to their receptor(s) in multiple relative orientations, an important multibinding design parameter. The only requirement for choosing attachment points is that attaching to at least one of these points does not abrogate activity of the 5- HT ligand. Such points for attachment can be identified by structural information when available. For example, inspection of a co-crystal structure of a protease inhibitor bound to its target allows one to identify one or more sites where linker attachment will not preclude the enzyme:inhibitor interaction. Alternatively, evaluation of ligand/target binding by nuclear magnetic resonance will permit the identification of sites non- essential for ligand/target binding. See, for example, Fesik, et al., U.S. Patent No. 5,891,643. When such structural information is not available, utilization of structure- activity relationships (SAR) for ligands will suggest positions where substantial structural variations are and are not allowed. In the absence of both structural and SAR information, a library is merely selected with multiple points of attachment to allow presentation of the ligand in multiple distinct orientations. Subsequent evaluation of this library will indicate what positions are suitable for attachment. It is important to emphasize that positions of attachment that do abrogate the activity of the monomeric ligand may also be advantageously included in candidate multibinding compounds in the library provided that such compounds bear at least one ligand attached in a manner which does not abrogate intrinsic activity. This selection derives from, for example, heterobivalent interactions within the context of a single target molecule. For example, consider a receptor agonist ligand bound to its target receptor, and then consider modifying this ligand by attaching to it a second copy of the same ligand with a linker which allows the second ligand to interact with the same receptor molecule at sites proximal to the antagonist binding site, which include elements of the receptor that are not part of the formal antagonist binding site and/or elements of the matrix surrounding the receptor such as the membrane. Here, the most favorable orientation for interaction of the second ligand molecule with the receptor/matrix may be achieved by attaching it to the linker at a position which abrogates activity of the ligand at the formal agonist binding site. Another way to consider this is that the SAR of individual ligands within the context of a multibinding structure is often different from the SAR of those same ligands in monomeric form. The foregoing discussion focused on bivalent interactions of dimeric compounds bearing two copies of the same ligand joined to a single linker through different attachment points, one of which may abrogate the binding/activity of the monomeric ligand. It should also be understood that bivalent advantage may also be attained with heterodimeric constructs bearing two different ligands, which may be agonists or antagonists, that bind to common or different targets. Once the ligand attachment points have been chosen, one identifies the types of chemical linkages that are possible at those points. The most preferred types of chemical linkages are those that are compatible with the overall structure of the ligand (or protected forms of the ligand) readily and generally formed, stable and intrinsically innocuous under typical chemical and physiological conditions, and compatible with a large number of available linkers. Amide bonds, ethers, amines, carbamates, ureas, and sulfonamides are but a few examples of preferred linkages. Linkers: spanning relevant multibinding parameters through selection of valency, linker length, linker geometry, rigidity, physical properties, and chemical functional groups In the library of linkers employed to generate the library of candidate multibinding compounds, the selection of linkers employed in this library of linkers takes into consideration the following factors: Valency. In most instances the library of linkers is initiated with divalent linkers. The choice of ligands and proper juxtaposition of two ligands relative to their binding sites permits such molecules to exhibit target binding affinities and specificities more than sufficient to confer biological advantage. Furthermore, divalent linkers or constructs are also typically of modest size such that they retain the desirable biodistribution properties of small molecules. Linker length. Linkers are chosen in a range of lengths to allow the spanning of a range of inter-ligand distances that encompass the distance preferable for a given divalent interaction. In some instances the preferred distance can be estimated rather precisely from high-resolution structural information of targets, typically enzymes and soluble receptor targets. In other instances where high-resolution structural information is not available (such as 7TM G-protein coupled receptors), one can make use of simple models to estimate the maximum distance between binding sites either on adjacent receptors or at different locations on the same receptor. In situations where two binding sites are present on the same target (or target subunit for multisubunit targets), preferred linker distances are 2-20 angstroms, with more preferred linker distances of 3-12 angstroms. In situations where two binding sites reside on separate (e.g., protein) target sites, preferred linker distances are 20-100 angstroms, with more preferred distances of 30-70 angstroms. Linker geometry and rigidity. The combination of ligand attachment site, linker length, linker geometry, and linker rigidity determine the possible ways in which the ligands of candidate multibinding compounds may be displayed in three dimensions and thereby presented to their binding sites. Linker geometry and rigidity are nominally determined by chemical composition and bonding pattern, which may be controlled and are systematically varied as another spanning function in a multibinding array. For example, linker geometry is varied by attaching two ligands to the ortho, meta, and para positions of a benzene ring, or in cis- or trans-arrangements at the 1,1- vs. 1,2- vs. 1,3- vs. 1 ,4- positions around a cyclohexane core or in cis- or trans-arrangements at a point of ethylene unsaturation. Linker rigidity is varied by controlling the number and relative energies of different conformational states possible for the linker. For example, a divalent compound bearing two ligands joined by 1,8-octyl linker has many more degrees of freedom, and is therefore less rigid than a compound in which the two ligands are attached to the 4,4' positions of a biphenyl linker. Linker physical properties. The physical properties of linkers are nominally determined by the chemical constitution and bonding patterns of the linker, and linker physical properties impact the overall physical properties of the candidate multibinding compounds in which they are included. A range of linker compositions is typically selected to provide a range of physical properties (hydrophobicity, hydrophilicity, amphiphilicity, polarization, acidity, and basicity) in the candidate multibinding compounds. The particular choice of linker physical properties is made within the context of the physical properties of the ligands they join and preferably the goal is to generate molecules with favorable PK/ADME properties. For example, linkers can be selected to avoid those that are too hydrophilic or too hydrophobic to be readily absorbed and/or distributed in vivo. Linker chemical functional groups. Linker chemical functional groups are selected to be compatible with the chemistry chosen to connect linkers to the ligands and to impart the range of physical properties sufficient to span initial examination of this parameter. Combinatorial synthesis Having chosen a set of n ligands (n being determined by the sum of the number of different attachment points for each ligand chosen) and m linkers by the process outlined above, a library of (n!)m candidate divalent multibinding compounds is prepared which spans the relevant multibinding design parameters for a particular target. For example, an array generated from two ligands, one which has two attachment points (Al, A2) and one which has three attachment points (Bl, B2, B3) joined in all possible combinations provide for at least 15 possible combinations of multibinding compounds: Al-Al A1-A2 Al-Bl A1-B2 A1-B3 A2-A2 A2-B1 A2-B2 A2-B3 Bl-Bl B1-B2 B1-B3 B2-B2 B2-B3 B3-B3 When each of these combinations is joined by 10 different linkers, a library of 150 candidate multibinding compounds results. Given the combinatorial nature of the library, common chemistries are preferably used to join the reactive functionalities on the ligands with complementary reactive functionalities on the linkers. The library therefore lends itself to efficient parallel synthetic methods. The combinatorial library can employ solid phase chemistries well known in the art wherein the ligand and/or linker is attached to a solid support. Alternatively and preferably, the combinatorial library is prepared in the solution phase. After synthesis, candidate multibinding compounds are optionally purified before assaying for activity by, for example, chromatographic methods (e.g., HPLC). Analysis of array by biochemical, analytical, pharmacological, and computational methods Various methods are used to characterize the properties and activities of the candidate multibinding compounds in the library to determine which compounds possess multibinding properties. Physical constants such as solubility under various solvent conditions and logD/clogD values can be determined. A combination of NMR spectroscopy and computational methods is used to determine low-energy conformations of the candidate multibinding compounds in fluid media. The ability of the members of the library to bind to the desired target and other targets is determined by various standard methods, which include radioligand displacement assays for receptor and ion channel targets, and kinetic inhibition analysis for many enzyme targets. In vitro efficacy, such as for receptor agonists and antagonists, ion channel blockers, and antimicrobial activity, can also be determined. Pharmacological data, including oral absoφtion, everted gut penetration, other pharmacokinetic parameters and efficacy data can be determined in appropriate models. In this way, key structure-activity relationships are obtained for multibinding design parameters that are then used to direct future work. The members of the library which exhibit multibinding properties, as defined herein, can be readily determined by conventional methods. First those members which exhibit multibinding properties are identified by conventional methods as described above including conventional assays (both in vitro and in vivo). Second, ascertaining the structure of those compounds which exhibit multibinding properties can be accomplished via art recognized procedures. For example, each member of the library can be encrypted or tagged with appropriate information allowing determination of the structure of relevant members at a later time. See, for example, Dower, et al., International Patent Application Publication No. WO 93/06121; Brenner, et al., Proc. Natl. Acad. Sci., USA, 89:5181 (1992); Gallop, et al., U.S. Patent No. 5,846,839; each of which are incoφorated herein by reference in its entirety. Alternatively, the structure of relevant multivalent compounds can also be determined from soluble and untagged libraries of candidate multivalent compounds by methods known in the art such as those described by Hindsgaul, et al., Canadian Patent Application No. 2,240,325 which was published on July 11, 1998. Such methods couple frontal affinity chromatography with mass spectroscopy to determine both the structure and relative binding affinities of candidate multibinding compounds to receptors. The process set forth above for dimeric candidate multibinding compounds can, of course, be extended to trimeric candidate compounds and higher analogs thereof. Follow-up synthesis and analysis of additional array(s) Based on the information obtained through analysis of the initial library, an optional component of the process is to ascertain one or more promising multibinding "lead" compounds as defined by particular relative ligand orientations, linker lengths, linker geometries, etc. Additional libraries can then be generated around these leads to provide for further information regarding structure to activity relationships. These arrays typically bear more focused variations in linker structure in an effort to further optimize target affinity and/or activity at the target (antagonism, partial agonism, etc.), and/or alter physical properties. By iterative redesign/analysis using the novel principles of multibinding design along with classical medicinal chemistry, biochemistry, and pharmacology approaches, one is able to prepare and identify optimal multibinding compounds that exhibit biological advantage towards their targets and as therapeutic agents. To further elaborate upon this procedure, suitable divalent linkers include, by way of example only, those derived from dicarboxylic acids, disulfonylhalides, dialdehydes, diketones. dihalides, diisocyanates, diamines, diols, mixtures of carboxylic acids, sulfonylhalides, aldehydes, ketones, halides, isocyanates, amines and diols. In each case, the carboxylic acid, sulfonylhalide, aldehyde, ketone, halide, isocyanate, amine and diol functional group is reacted with a complementary functionality on the ligand to form a covalent linkage. Such complementary functionality is well known in the art as illustrated in the following table: COMPLEMENTARY BINDING CHEMISTRIES First Reactive Group Second Reactive Group Linkage hydroxyl isocyanate urethane amine epoxide β-hydroxyamine sulfonyl halide amine sulfonamide carboxyl acid amine amide hydroxyl alkyl/aryl halide ether aldehyde amine/NaCNBH 4 amine ketone amine/NaCNBH 4 amine amine isocyanate urea Exemplary linkers include those described in the Appendix. Pharmaceutical Formulations When employed as pharmaceuticals, the compounds of the invention are usually administered in the form of pharmaceutical compositions. These compounds can be administered by a variety of routes including oral, rectal, transdermal, subcutaneous, intravenous, intramuscular, and intranasal. These compounds are effective as both injectable and oral compositions. Such compositions are prepared in a manner well known in the pharmaceutical art and comprise at least one active compound. This invention also includes pharmaceutical compositions that contain, as the active ingredient, one or more of the compounds of formula I above associated with one or more pharmaceutically acceptable carriers. In making the compositions of this invention, the active ingredient is usually mixed with an excipient, diluted by an excipient or enclosed within such a carrier which can be in the form of a capsule, sachet, paper or other container. When the excipient serves as a diluent, it can be a solid, semi- solid, or liquid material, which acts as a vehicle, carrier or medium for the active ingredient. Thus, the compositions can be in the form of tablets, pills, powders, lozenges, sachets, cachets, elixirs, suspensions, emulsions, solutions, syrups, aerosols (as a solid or in a liquid medium), ointments containing, for example, up to 10% by weight of the active compound, soft and hard gelatin capsules, suppositories, sterile injectable solutions, and sterile packaged powders. In preparing a formulation, it may be necessary to mill the active compound to provide the appropriate particle size prior to combining with the other ingredients. If the active compound is substantially insoluble, it ordinarily is milled to a particle size of less than 200 mesh. If the active compound is substantially water soluble, the particle size is normally adjusted by milling to provide a substantially uniform distribution in the formulation, e.g. about 40 mesh. Some examples of suitable excipients include lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, tragacanth, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, sterile water, syrup, and methyl cellulose. The formulations can additionally include: lubricating agents such as talc, magnesium stearate, and mineral oil; wetting agents; emulsifying and suspending agents; preserving agents such as methyl- and propylhydroxy-benzoates; sweetening agents; and flavoring agents. The compositions of the invention can be formulated so as to provide quick, sustained or delayed release of the active ingredient after administration to the patient by employing procedures known in the art. The compositions are preferably formulated in a unit dosage form, each dosage containing from about 0.1 mg to about 1 g, more usually about 1 to about 100 mg, of the active ingredient. The term "unit dosage forms" refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical excipient. Preferably, the compound of formula I above is employed at no more than about 20 weight percent of the pharmaceutical composition, more preferably no more than about 15 weight percent, with the balance being pharmaceutically inert carrier(s). The active compound is effective over a wide dosage range and is generally administered in a pharmaceutically effective amount. It, will be understood, however, that the amount of the compound actually administered will be determined by a physician, in the light of the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compound administered, the age, weight, and response of the individual patient, the severity of the patient's symptoms, and the like. For preparing solid compositions such as tablets, the principal active ingredient is mixed with a pharmaceutical excipient to form a solid preformulation composition containing a homogeneous mixture of a compound of the present invention. When referring to these preformulation compositions as homogeneous, it is meant that the active ingredient is dispersed evenly throughout the composition so that the composition may be readily subdivided into equally effective unit dosage forms such as tablets, pills and capsules. This solid preformulation is then subdivided into unit dosage forms of the type described above containing from, for example, 0.1 to about 500 mg of the active ingredient of the present invention. The tablets or pills of the present invention may be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action. For example, the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. The two components can be separated by an enteric layer which serves to resist disintegration in the stomach and permit the inner component to pass intact into the duodenum or to be delayed in release. A variety of materials can be used for such enteric layers or coatings, such materials including a number of polymeric acids and mixtures of polymeric acids with such materials as shellac, cetyl alcohol, and cellulose acetate. The liquid forms in which the novel compositions of the present invention may be incoφorated for administration orally or by injection include aqueous solutions, suitably flavored syrups, aqueous or oil suspensions, and flavored emulsions with edible oils such as corn oil, cottonseed oil, sesame oil, coconut oil, or peanut oil, as well as elixirs and similar pharmaceutical vehicles. Compositions for inhalation or insufflation include solutions and suspensions in pharmaceutically acceptable, aqueous or organic solvents, or mixtures thereof, and powders. The liquid or solid compositions may contain suitable pharmaceutically acceptable excipients as described supra. Preferably the compositions are administered by the oral or nasal respiratory route for local or systemic effect. Compositions in preferably pharmaceutically acceptable solvents may be nebulized by use of inert gases. Nebulized solutions may be inhaled directly from the nebulizing device or the nebulizing device may be attached to a face mask tent, or intermittent positive pressure breathing machine. Solution, suspension, or powder compositions may be administered, preferably orally or nasally, from devices that deliver the formulation in an appropriate manner. Actual methods of preparing such dosage forms are known, or will be apparent, to those skilled in this art; for example, see Remington's Pharmaceutical Sciences, Mack Publishing Company, Easton, Pennsylvania. 19th Edition, 1995, the complete disclosure of which is hereby incoφorated by reference. The composition or formulation to be administered will, in any event, contain a quantity of the active compound(s) in an amount effective to alleviate the symptoms of the subject being treated. UTILITY The multibinding agents of the invention are useful in medical treatments related to the inhibition of bacterial type II DNA topoisomerases, and accordingly exhibit biological effects well known to those skilled in the art, in particular antibacterial activity, which can be demonstrated in the tests described herein. Assays for antibacterial activity are well known to those skilled in the art, and are referenced and described in the fourth edition of "Antibiotics in Laboratory Medicine", by Victor Lorian, M.D., published by Williams and Wilkins, which is hereby incoφorated by reference. Additionally, see Antimicrobial Agents and Chemotherapy, Vol. 35, pp 910-915 (1991), Antimicrobial Agents and Chemotherapy, Vol. 35, pp 1489-1491 (1991), Antimicrobial Agents and Chemotherapy, Vol. 40, pp 2714-2720 (1996), and Proceedings of the National Academy of Sciences, Vol. 67, pp 674-681 (1970). METHODS OF PREPARATION Linker The linker (or linkers), when covalently attached to multiple copies of the ligands, provides a biocompatible, substantially non-immunogenic multibinding agent. The biological effects of the multibinding agent are highly sensitive to the valency, geometry, composition, size, flexibility or rigidity, the presence or absence of anionic or cationic charge, and similar considerations (including hydrophilicity and hydrophobicity as discussed below) with respect to the linker. Accordingly, the linker is preferably chosen to maximize the desired biological effect. The linker may be biologically "neutral", i.e. not itself contribute any biological activity to the compound of Formula I, or it may be chosen to enhance the biological effect of the molecule. In general, the linker may be chosen from any organic molecule that orients two or more ligands to the ligand binding sites, and permits multivalency. In this regard, the linker can be considered as a "framework" on which the ligands are arranged in order to bring about the desired ligand-orienting result, and thus produce a multibinding agent. For example, different orientations can be achieved by including in the framework groups containing monocyclic or polycyclic groups, including aryl and heteroaryl groups, or structures incoφorating one or more carbon-carbon multiple bonds (i.e., alkenes and alkynes). Other groups can also include oligomers and polymers which are branched- or straight-chain species. In preferred embodiments, rigidity is imparted by the presence of cyclic groups (e.g., aryl, heteroaryl, cycloalkyl, heterocycles, etc.). In other preferred embodiments, the ring is a six-or ten membered ring. In still further preferred embodiments, the ring is an aromatic group such as, for example, phenyl or naphthyl. Different frameworks can be designed to provide preferred orientations of the ligands. Such frameworks may be represented by using an array of dots (as shown below) wherein each dot may potentially be an atom, such as C, O, N, S, P, H, F, Cl, Br, and F, or the dot may alternatively indicate the absence of an atom at that position. To facilitate the understanding of the framework structure, the framework is illustrated as a two dimensional array in the following diagram, although clearly the framework is a three dimensional array in practice: Each dot is either an atom, chosen from carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus, or halogen, or the dot represents a point in space (i.e. an absence of an atom). Only certain atoms on the grid have the ability to act as an attachment point for the ligands, namely C, O, N, S, and P. Atoms can be connected to each other via bonds (single, double, or triple with acceptable resonance and tautomeric forms), with regard to the usual constraints of chemical bonding. Ligands may be attached to the framework via single, double, or triple bonds (with chemically acceptable tautomeric and resonance forms). Multiple ligand groups (2 to 10) can be attached to the framework such that the minimal, shortest path distance between adjacent ligand groups does not exceed 100 atoms or 40 angstroms. An example of a linker as represented by the grid is shown below for a biphenyl construct. Nodes (1,2), (2.0), (4,4), (5,2), (4,0), (6,2), (7,4), (9,4), (10,2), (9,0), (7,0) all represent carbon atoms. Node (10,0) is a chlorine atom. All other nodes (or dots) are points in space (i.e. represent an absence of atoms). Nodes (1,2) and (9,4) are attachment points. Hydrogen atoms are affixed to nodes (2,4), (4,4), (4,0), (2,0), (7,4), (10,2), and (7,0). Nodes (5.2) and (6,2) are connected by a single bond. The carbon atoms present are connected by either single or double bonds, taking into consideration the principle of resonance and/or tautomerism. The intersection of the framework (linker) and the ligand group, and indeed, the framework (linker) itself can have many different bonding patterns. Examples of acceptable patterns of three contiguous atom arrangements within the linker and at the linker-ligand interface are shown in the following diagram. ccc NCC CCN NCN occ sec cc CCO CN NCO OCN SCN CCS OCO SCO CO CCP NCS s NCP ocs sc OCP SCP cs CP NC NNC NN ONC SNC NC NO N N N ONN SN N NN NNO NS ONO STTO NO NP NNS SNS NS N N P cπrs " ONP SNP NP CSC CSN NSC osc PSC NSN OS CSO SSN PSN c SS NSO OS SSO P ~ S ~ 0 c SP NSS OS OS s-s-S " FB " S NSP OS -ST p-s PC PN NPC PPC NPN o PO NPO o PS O PP NPS o P NPP o p ~ s- o p-p-p One skilled in the art would be able to identify bonding patterns that would produce multivalent compounds. Methods for producing these bonding arrangements are described in "Advanced Organic Chemistry, 4 th Edition" by March (Wiley-Interscience (New York). 1992). These arrangements are described in the grid of dots shown in the Scheme above. All of the possible arrangements for the five most preferred atoms are shown. Each atom has a variety of acceptable oxidation states. The bonding arrangements underlined are less acceptable and are not preferred. Examples of molecular structures in which the above bonding patterns could be employed as components of the linker are shown below. o o ° o -N Λ N- W W ^ Figure 4 The identification of an appropriate framework geometry for ligand domain presentation is an important first step in the construction of a multivalent binding agent with enhanced activity. Systematic spatial searching strategies can be used to aid in the identification of preferred frameworks through an iterative process. Various strategies are known to those skilled in the art of molecular design and can be used for preparing the compounds of this invention. As shown in Figure 4, display vectors around similar central core structures such as phenyldiacetylene and cyclohexane dicarboxylic acid can be varied, as can the spacing of the ligand domain from the core structure (i.e., the length of the attaching moiety). It is to be noted that core structures other than those shown here can be used for determining the optimal framework display orientation of the ligands. The process may require the use of multiple copies of the same central core structure or combinations of different types of display cores. The above-described technique can be extended to trimers and compounds of higher-order valency as exemplified by structures shown in Figure 4. Assay of each of the individual compounds of a collection generated as described above will lead to a subset of compounds with the desired enhanced activities (e.g., potency, selectivity). The analysis of this subset using a technique such as Ensemble Molecular Dynamics will provide a framework orientation that favors the properties desired. A wide diversity of linkers is commercially available (see, e.g., the Available Chemicals Directory, (ACD), Chem. Sources USA, Chem. Sources International, Chemical Abstracts). Many of the linkers that are suitable for use in this invention fall into this category. Others can be readily synthesized, e.g., by methods known in the art and described below. Having selected a preferred framework geometry, the physical properties of the linker can be optimized by varying the chemical composition. The composition of a linker can be varied in numerous ways to achieve the desired physical properties. It can therefore be seen that there is a plethora of possibilities for the composition of a linker. Examples of linkers include aliphatic moieties, aromatic moieties, steroidal moieties, peptides, and the like. Specific examples are peptides or polyamides, hydrocarbons, aromatic groups, ethers, lipids, cationic or anionic groups, or a combination thereof, and many specific examples of linkers are shown in Figure 4. Examples are given below, but it should be understood that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. For example, properties of the linker can be modified by the addition or insertion of ancillary groups into the linker, for example, to change solubility of the multibinding agent (in water, fats, lipids, biological fluids, etc.), hydrophobicity, hydrophilicity. linker flexibility, antigenicity, molecular size, molecular weight, in vivo half-life, in vivo distribution, biocompatability, immunogenicity, stability, and the like. For example, the introduction of one or more poly or preferably oligo(ethylene glycol) (PEG) groups onto the linker enhances hydrophilicity and water solubility of the multibinding agent, increases both molecular weight and molecular size and, depending on the nature of the unPEGylated linker, may increase the in vivo retention time. Further, PEG may decrease antigenicity and potentially enhances the overall rigidity of the linker. Ancillary groups that enhance the water solubility/hydrophilicity of the linker are useful in practicing the present invention. Thus, it is within the scope of the present invention to use ancillary groups such as, for example, poly(ethylene glycol), alcohols, polyols (e.g., glycerin, glycerol propoxylate, saccharides, including mono-, oligo- and polysaccharides, etc.), carboxylates, polycarboxylates (e.g., polyglutamic acid, polyacrylic acid, etc.), amines, polyamines (e.g., polylysine, poly(ethyleneimine), etc) to enhance the water solubility and/or hydrophilicity of the compounds of Formula I. In preferred embodiments, the ancillary group used to improve water solubility/hydrophilicity will be a polyether. In particularly preferred embodiments, the ancillary group will be a poly(ethylene glycol). The incoφoration of lipophilic ancillary groups within the structure of the linker to enhance the lipophilicity and/or hydrophobicity of the compounds of Formula I is within the scope of the present invention. Lipophilic groups of use in practicing the instant invention include, but are not limited to, aryl and heteroaryl groups. The aromatic groups may be either unsubstituted or substituted with other groups, but are at least substituted with a group which allows their covalent attachment to the linker. Other lipophilic groups of use in practicing the instant invention include fatty acid derivatives which do not form bilayers in aqueous medium until higher concentrations are reached. Also within the scope of the present invention is the use of ancillary groups which result in the compound of Formula I being incoφorated into a vesicle such as a liposome or a micelle. The term "lipid" refers to any fatty acid derivative that is capable of forming a bilayer or micelle such that a hydrophobic portion of the lipid material orients toward the bilayer while a hydrophilic portion orients toward the aqueous phase. Hydrophilic characteristics derive from the presence of phosphato, carboxylic, sulfato, amino, sulfhydryl, nitro, and other like groups. Hydrophobicity could be conferred by the inclusion of groups that include, but are not limited to, long chain saturated and unsaturated aliphatic hydrocarbon groups of up to 20 carbon atoms and such groups substituted by one or more aryl, heteroaryl, cycloalkyl and/or heterocyclic group(s). Preferred lipids are phosphoglycerides and sphingolipids, representative examples of which include phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, phosphatidic acid, palmitoyloleoyl phosphatidylcholine, lysophosphatidylcholine, lysophosphatidyl-ethanolamine, dipalmitoylphosphatidylcholine, dioleoylphosphatidylcholine, distearoyl- phosphatidylcholine or dilinoleoylphosphatidylcholine could be used. Other compounds lacking phosphorus, such as sphingolipid and glycosphingolipid families are also within the group designated as lipid. Additionally, the amphipathic lipids described above may be mixed with other lipids including triglycerides and sterols. The flexibility of the linker can be reduced by the inclusion of ancillary groups which are bulky and/or rigid. The presence of bulky or rigid groups can hinder free rotation about bonds in the linker or bonds between the linker and the ancillary group(s) or bonds between the linker and the functional groups. Rigid groups can include, for example, those groups whose conformational lability is restrained by the presence of rings and/or multiple bonds, for example, aryl, heteroaryl, cycloalkyl, and/or heterocyclic. Other groups which can impart rigidity include polymeric groups such as oligo- or polyproline chains. Rigidity can also be imparted electrostatically. Thus, if the ancillary groups are either negatively or positively charged, the similarly charged ancillary groups will force the presenter linker into a configuration affording the maximum distance between each of the like charges. The energetic cost of bringing the like-charged groups closer to each other will tend to hold the linker in a configuration that maintains the separation between the like-charged ancillary groups. Further, ancillary groups bearing opposite charges will tend to be attracted to their oppositely charged counteφarts and potentially may enter into both inter- and intramolecular ionic bonds. This non-covalent bonding mechanism will tend to hold the linker into a conformation which allows bonding between the oppositely charged groups. The addition of ancillary groups which are charged, or alternatively, bear a latent charge which is unmasked, following addition to the linker, by deprotection, a change in pH, oxidation, reduction or other mechanisms known to those of skill in the art, is within the scope of the present invention. Rigidity may also be imparted by internal hydrogen bonding, or by hydrophobic collapse. Bulky groups can include, for example, large atoms and/or ions (e.g., iodine, sulfur, metal ions, etc.) groups containing large atoms, polycyclic groups, including aromatic groups, non-aromatic groups and structures incoφorating one or more carbon- carbon multiple bonds (i.e., alkenes and alkynes). Bulky groups can also include oligomers and polymers which are branched- or straight-chain species. Species that are branched are expected to increase the rigidity of the structure more per unit molecular weight gain than are straight-chain species. Eliminating or reducing antigenicity of the compounds of Formula I by judicious choice of ancillary group(s) is within the scope of the present invention. In certain applications, the antigenicity of a compound of Formula I may be reduced or eliminated by the use of groups such as, for example, poly(ethylene glycol). As explained above, the multibinding agents of the invention comprise 2-10 ligands attached to a linker that connects the ligands in such a manner that they are presented to the appropriate receptors (ligand binding sites) for multivalent interactions. The linker spatially constrains these interactions to occur within dimensions defined by the linker, thus increasing the biological effect of the multibinding agent as compared to the same number of individual units of the ligand. The multivalent compounds of the invention, the compounds of Formula I, are represented by the empirical formula (L) p (X) q . This is intended to include the several ways in which the ligands can be linked together in order to achieve the objective of multivalency, and a more detailed explanation is given below. However, as previously noted, the linker can be considered as a framework, and it should be understood that the ligands can be attached to this framework at any intermediate point on the framework, and/or on the termini of the framework. For example, if the linker is a linear chain, a bivalent compound can be constructed by attaching two ligands at the two ends of the linear chain, or alternatively attaching two ligands at some intermediate atom along the chain. The same considerations apply to the compounds of the present invention containing more than 2 ligands. The simplest (and preferred) multibinding agent is a bivalent compound, which can be represented as L-X-L, where L is a ligand and is the same or different, and X is the linker. It should be noted that the linker X can be linear or cyclic, or a combination of both linear and cyclic constructs, and that the two ligands may be located at the termini of the linker or may be attached at some intermediate attachment point. The same is true for a trivalent compound, which can also be represented in a linear fashion, i.e. as a sequence of repeated units L-X-L-X-L, in which L is a ligand and is the same or different at each occurrence, as can X. or a compound comprising three ligands attached to a central core, and thus represented as (L) 3 X, where the linker X could include, for example, an aryl or cycloalkyl group. The same considerations of geometry apply to the compounds of the present invention containing 4-10 ligands. For example, a tetravalent compound could be represented as L-X-L-X-L-X-L, or L-X-L-X-L L i.e. a branched construct analogous to the isomers of butane (n-butyl, sec-butyl, tert- butyl). Alternatively, it could be represented as an aryl or cycloalkyl derivative as above with four ligands attached to the core linker. The same principles apply to the higher multibinding agents, e.g. pentavalent to decavalent compounds. However, for multibinding agents attached to a central linker such as benzene, there is the self-evident constraint that there must be sufficient attachment sites on the linking moiety to accommodate the number of ligands present; for example, a benzene ring could not accommodate more than six ligands, whereas a saturated and/or multi-ring linker (cyclohexyl, cyclooctyl, biphenyl, etc.) could accommodate a larger number of ligands. The formula (L) p (X) q is also intended to represent a cyclic compound of formula (-L-X-) n , where n is 2-10. For example, where n is 3: X L L X X L All of the above variations are intended to be within the scope of the invention as defined by the Formula I (L) p (X) q . The preferred linker length will vary depending upon the distance between adjacent ligand recognition sites, and the geometry, flexibility and composition of the linker. The length of the linker will preferably be in the range of about 2-100 Angstroms, more preferably about 2-50 Angstroms, and even more preferably about 3-20 Angstroms. With the foregoing in mind, preferred linkers may be represented by the following formula: -X'-Z-(Y'-Z) m -Y"-Z-X'- in which: m is an integer of 0-20; X' at each separate occurrence is -0-, -S-, -S(O)-, -S(0) 2 -, -NR- (where R is as defined below), -C(O)-, or a covalent bond; Z at each separate occurrence is alkylene, cycloalkylene, alkenylene, alkynylene, arylene, heteroarylene, or a covalent bond; Y " and Y" at each separate occurrence are S-S-, or a covalent bond; in which: n is 0, 1 or 2; and R, R' and R" at each separate occurrence are chosen from hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, heteroaryl, and heterocyclo. Additionally, the linker moiety can be optionally substituted at any atom in the chain by alkyl, cycloalkyl, alkenyl, alkynyl, alkoxy, halo, nitro, aryl, heteroaryl, or heterocyclo. Preparation of Compounds of the Invention The simplest (and preferred) construct is a bivalent compound, which can be represented as L-X-L, where L is a ligand that is the same or different at each occurrence, and X is the linker. Accordingly, an example of the preparation of a bivalent multibinding agent is given below as an illustration of the manner in which multibinding agents of the invention are obtained. As indicated above, one class of ligands includes the quinolones, a preferred class of which may be represented by Formula II. Examples are shown in Figure 1. nalidixic acid piromidic acid pipermidic acid oxolinic acid cinoxacin miloxacin norfloxacin ciprofloxacm ofloxacin pefloxacin tlerofloxacin flumequine lomefloxacin temafloxacin sparfloxacin FIGURE 1 For example, norfloxacin is a compound of Formula II in which R 1 is ethyl, R 2 , R 4 and R 5 are hydrogen, Y is -CR 6 - in which R 6 is fluoro, Z is -CR 8 - in which R 8 is hydrogen, and R is 1-piperazine. norfloxacin Similarly, ciprofloxacin is a compound of Formula II in which R 1 is cyclopropyl, R 2 , R 4 and R 5 are hydrogen, Y is -CR 6 - in which R is fluoro, Z is -CR - in which R 8 is hydrogen, and R 7 is 1-piperazine. o o Y OH ciprofloxacin Similarly, ofloxacin is a compound of Formula II in which R and R when taken together with the atoms to which they are attached represents 3-methylmoφholinyl, R 2 , R 4 and R 5 are hydrogen, Y is -CR 6 - in which R 6 is fluoro, and R 7 is 1-piperazine. Ligands can be linked at any of the positions available, using known synthetic methodology. However, it is preferred that R is hydrogen and R is COOH. Accordingly, the preferred linking positions are at the ring nitrogen R 1 , at R 7 , at R 5 and R . Linking at the other positions is also within the scope of the present invention, for example from any position on the piperazine group of the above identified ligands. In some cases, it is preferred to link ligands directly, using the functionality already present in the known drug. For example, a ring nitrogen may be used for direct linking. In other cases, it is preferred to accomplish linking indirectly by first preparing an intermediate that upon reaction yields the multibinding agents of the invention. Such intermediates may be commercially available, or are prepared by means well known in the art. The intermediates can be linked to each other before the intermediate is modified to the target ligand structure, or linking can occur after such modification. In some cases, it may be necessary to protect portions of the ligand that are not involved in linking reactions; protecting groups are well known to those skilled in the art. Examples of the preparation and use of such intermediates are shown below. In general, the ligand or the ligand intermediate is reacted with a 'core' molecule having two or more functional groups with reactivity that is complementary to that of the functional groups on the ligand, thus linking ligands by a linker. Selecting different core molecules allows control of linker size, shape, orientation, rigidity, acidity/basicity, hydrophobicity /hydrophilicity, hydrogen bonding characteristics, and number of ligands connected. Examples of "cores" are shown below in Figure 2. The solid circle is used in the following figures and reaction schemes to represent any of the possible core molecules. That is, the solid (or shaded) circle is equivalent to a linker as defined above after reaction. Alkjl Cores ^- ^^\ * ^ $ 9 Ether Cores Aromatic Cores ft Λ • -ψ I i γ J ≠ ^ Λcidic/Basic Cores Peptidic Cores FIGURE 2 The preferred compounds of the invention are bivalent. Accordingly, for the sake of simplicity, the following figures and reaction schemes illustrate the synthesis of bivalent quinolones. It should be noted, however, that the same techniques can be used to prepare multibinding agents that are derived from ligands other than quinolones, and also to generate higher order multibinding compounds, i.e. the compounds of the invention where n is 3-10. SYNTHESES OF BIVALENT COMPOUNDS In the quinolone class, linking at the R 1 position can be achieved by starting with a monovalent quinolone where R 1 is hydrogen. Using this strategy, the ring NH on the quinolone is coupled to two or more appropriate electrophihc groups presented by the core. Reaction Scheme I demonstrates this strategy where the electrophihc groups chosen are bromo derivatives. One skilled in the art would recognize that many electrophiles equivalent to bromides (for example, other halides, mesylates, tosylates, etc.) may be used. The reaction is preferably carried out in a polar aprotic solvent (e.g. DMF, DMA, DMPU) in the presence of a base, preferably sodium hydride. REACTION SCHEME I (2) where PG represents a protecting group, preferably lower alkyl, and the shaded circle represents a linker. Linking at the R 1 position can also be accomplished indirectly by preparing a intermediate, which can, in one step, be linked to a core and cyclized to form the quinolone, as shown in Reaction Scheme II REACTION SCHEME II (4) where R is a protecting group, preferably lower alkyl. Linking two ligands through the R 7 sidechain can be accomplished directly where an amine is present at this position, for example a piperazine. Many methods of coupling the amine to an electrophihc groups presented by the core are well known in the art. For example, an amine can be reacted with a core that includes halides (as shown above), with aldehydes (reductive amination), with carboxylic acids, with acid chlorides, with haloformates. and with isocyanates, as shown in Reaction Scheme III. REACTION SCHEME III DMF Linking two ligands at aromatic ring positions R 5 , R 7 , and R 8 can be accomplished by reacting intermediates having halogens at these positions, preferably fluorine, with cores presenting nucleophiles such as alcohols, thiols, and amines, as shown in Reaction Scheme IV. Coupling with alcohols or thiols requires the addition of a strong base such as sodium hydride. For polyfluorinated quinolones, the structure of the intermediate determines the position of substitution. If positions R\ R 6 , R 7 , and R 8 are all fluorine, a nucleophile can be selectively coupled to R 3 or R 7 , depending primarily on the substituent at R 3 . If R 3 is COOH, the nucleophile is directed to R 7 , if it is COOR (an ester) the nucleophile is directed to R 5 . Once a larger substituent has been added to the ring, it will direct subsequent couplings. A substituent at R 5 favors coupling at R 7 ; a substituent at R 7 favors coupling at R 5 . This is a preferred strategy for linking quinolone monomers at R ~ \ and an alternate preferred strategy for linking at R 7 . REACTION SCHEME IV Linking at the 5-Position (11a) Linking at the 7 and 8 -Positions Formula I Formula 1 where R 9 NH 2 represents any primary amine. For example. R 9 can be alkyl, cycloalkyl, aryl, heteroaryl. heterocyclo, and the like, preferably R 5 ^^ represents a cyclic amine such as piperazine or moφholine, any of which are optionally substituted. The R position can be accessed for linking through an intermediate that is not fluorinated at R\ and has been substituted at R 7 . A preferred procedure for preparing compounds of the invention linked at the 5- position is by solid phase parallel synthesis. One example (using a diamino linker) proceeds via a compound of formula (28), the preparation of which is shown in Reaction Scheme V. REACTION SCHEME V where NHC(0)QNH 2 is a "spacer" as defined below, in which Q is preferably (CH 2 ) n , where n is 1-5, and the shaded circle represents a linker as defined above that is attached to two amino functional groups. In general, a commercially available resin, for example Argogel MBCHO, is reacted with the appropriate diamine in the presence of sodium triacetoxyborohydride to give the compound of formula (27). Compound (27) is then reacted with a protected amino acid (for example, Fmoc β-alanine) followed by appropriate deprotection , for example using piperidine in a polar solvent, for example dimethylformamide, to give the compound of formula (28). The compound of formula (28) is then reacted with an appropriately substituted ligand to provide a bivalent compound of formula I. as shown in Reaction Scheme VI. REACTION SCHEME VI Formula I In general, the quinolone is dissolved in a polar aprotic solvent, preferably 1 ,3- dimethyl-3,4,5,6-tetrahydro-2(lH)-pyrimidinone (DMPU) in the presence of a hindered base (for example, DIPEA), and reacted at an elevated temperature, for example about 60-100°C, for about 6-24 hours. After the reaction is substantially complete, the compound of Formula I is cleaved from the resin using a strong acid, preferably TFA plus 5% water. A table of preferred diamines is shown in the appendix. All of the strategies for preparing multibinding agents discussed above involve a single step in which the ligand is coupled directly to a central multifunctional core. However, an alternate preferred strategy involves first introducing a bifunctional 'spacer' that can be coupled, after deprotection if necessary, to an appropriate core. The structure of the spacer can be chosen from the same set as the possible core structures, and is represented by a gray circle below, but may have nonequivalent functional groups at the ends. Representative examples of this strategy applied to making dimers at the 1 and 7 positions are shown in Reaction Scheme VII. This strategy may be applied to linking at any position, of any monomeric ligand, to make dimers and higher order multibinding compounds. REACTION SCHEME VII A preferred procedure for preparing compounds of the invention linked at the 7- position is by solid phase parallel synthesis. One example (using a diamino linker) proceeds via a compound of formula (30), the preparation of which is shown in Reaction Scheme VIII. REACTION SCHEME VIII The reaction is carried out in a manner similar to that shown in Reaction Scheme V. The compound of formula (30) is then reacted with an appropriately substituted ligand to provide a bivalent compound of formula I, as shown in Reaction Scheme IX. REACTION SCHEME IX Formula I The reaction is carried out in a manner similar to that shown in Reaction Scheme VI. Preferred diamines are shown in the appendix. All of the synthetic strategies described above employ a step in which the ligand, attached to spacers or not, is linked to a central core in a single reaction to give a multibinding compound. This strategy is preferred when the target multibinding compound is symmetric. However, another preferred strategy for synthesizing bivalent compounds and higher order compounds (i.e. multibinding agents in which p is 3-10) is a linear approach. For example, linear synthesis is preferred when linking two or more ligands at different points of connectivity. For example, the R 1 position of one quinolone monomer can be linked to the R 7 position of another quinolone monomer, as shown in Reaction Scheme X. REACTION SCHEME X (23) A method of preparing multibinding agents where p is 3-10 is illustrated in Reaction Scheme XI, where the linking is a discontinuous chain of the form L-(X-L) p- ι. As illustrated, the ligands are linked from R 1 to R 7 along a discontinuous chain REACTION SCHEME XI (22) TFA (22) TFA (23) DIC DIC DIPEA DIPEA DMF DMF (24) Such a linear strategy can also be extended to the synthesis of multibinding agents comprising different ligands, i.e. multibinding agents in which L at each occurrence is different. Examples of such compounds are shown in Reaction Scheme XII, which are prepared by a simple extension of the strategies described above REACTION SCHEME XII (26) norfloxacin-ciprofloxacin ofloxacin-notfloxacin It should be noted that while all figures are drawn with aliphatic couplings for the sake of simplicity, an alternate linking strategy involves direct substitution on an aryl ring. An example of this is shown in Reaction Scheme XIII. REACTION SCHEME XIII This strategy can be used as a linking step. Isolation and Purification of the Compounds Isolation and purification of the compounds and intermediates described herein can be effected, if desired, by any suitable separation or purification procedure such as, for example, filtration, extraction, crystallization, column chromatography, thin-layer chromatography, thick-layer chromatography, preparative low or high-pressure liquid chromatography or a combination of these procedures. Specific illustrations of suitable separation and isolation procedures can be had by reference to the Examples hereinbelow. However, other equivalent separation or isolation procedures could, of course, also be used. The following abbreviations have the following meanings. If an abbreviation is not defined, it has its generally accepted meaning. BOC = tert-butyloxycarbonyl BTX = batrachotoxin Cbz = carbobenzyloxy DCC = N-N-dicyclohexylcarbodiimide DIPEA = diisopropylethylamine, Hunig's base DMA = N,N-dimethylacetamide DMF = N,N-dimethylformamide DMSO dimethylsulfoxide DPPA diphenylphosphoryl azide HATU 6-(7-azabenzotriazol- 1 -yl)-N,N,N'N'- tetramethyluronium hexafluorophosphate HBTU 1 -hydroxybenzotriazole HOAT 1 -hydroxy-7-azabenzotriazole PyBOP pyridine benzotriazol-1 -yloxy-tris(dimethyl- amino)phosphonium hexafluorophosphate TEA triethylamine TFA trifluoroacetic acid THF tetrahydrofuran EXAMPLE 1 Preparation of Compounds of Formula I A. Preparation of a Compound of Formula I, in which L is a compound of Formula II in which R 1 is Cyclopropyl, R 2 is Hydrogen, R 3 is Carboxy, R 6 and R 8 are Fluorine, and R 7 is 1-Piperazinyl, linked via the 5-Position by 1,3-Diaminopropane, p is 2 and q is 1 1 -Cyclopropyl-5 ,6,8-trifluoro-7-(4-methylpiperazin- 1 -yl)-4-oxo- 1 ,4- dihydroquinoline-3-carboxylic acid (a compound of Formula II, 0. 3g, 0.8 mmol), prepared according to the procedure in J Med Chem 1989, 32, 1313 ,was mixed with 0.033 mL (0.4 mmol) of 1 ,3-diaminopropane and 0.55 mL (3.2 mmol) of N,N- diisopropylethylamine in 4 mL of DMPU, and the mixture was heated at 85°C for 18 hours. The reaction mixture was cooled and precipitated from 30 mL of 2:1 Hexane/Ether. The crude precipitate was taken up in 5:1 0.5N HCl: acetonitrile and purified by reverse phase HPLC using a 10-60% acetonitrile (0.1% TFA) gradient over 60 min. Product peaks were determined by MS and purity analyzed by HPLC. The desired product fractions were combined and lyophilized to obtain a white fluffy solid. This material was then taken up in 40 mL of 0.25M HCl and lyophilized twice to yield 0.14 g (0.14 mmol, 17%) of N,N'-bis-(l-cyclopropyl-6,8-difluoro-7-(4-methylpiperazin- l-yl)-4-oxo-l,4-dihydroquinolin -3-carboxylic acid-5-yl)-l,3-diaminopropane as a dark yellow solid. B. Similarly, replacing 1 ,3-diaminopropane with: 1) 1 ,2-diaminoethane; 2) 1 ,4-diaminobutane; 3) 1,5-diaminopentane; 4) 1 ,6-diaminohexane; 5) 1 ,9-diaminononane; 6) 3 - { 2- [2-(3 -aminopropoxy)ethoxy]ethoxy } propylamine; 7) 1 ,3-bis (aminomethyl)benzene; 8) 1 ,4-bis-(aminomethyl)benzene; and 9) 2-(2-aminoethoxy)ethylamine: the following compounds of Formula I were prepared: 1) N,N'-bis-(l -cyclopropyl-6,8-difluoro-7-ι (4-methylpiperazin- 1 -y l)-4-oxo- 1 ,4- dihydroquinolin -3-carboxylic acid-5-yl )- 1 ,2-diaminoethane; 2) N,N'-bis-(l -cyclopropyl-6,8-difluoro-7-ι (4-methylpiperazin- 1 -yl)-4-oxo- 1 ,4- dihydroquinolin -3-carboxylic acid-5-yl )- 1 ,4-diaminobutane; 3) N,N'-bis-(l-cyclopropyl-6,8-difluoro-7-< (4-methylpiperazin- 1 -yl)-4-oxo- 1 ,4- dihydroquinolin -3-carboxylic acid-5-yl )- 1 ,5-diaminopentane; 4) N,N'-bis-(l-cyclopropyl-6,8-difluoro-7 (4-methylpiperazin- 1 -yl)-4-oxo-l ,4- dihydroquinolin -3-carboxylic acid-5-yl )- 1 ,6-diaminohexane; 5) N,N'-bis-( 1 -cyclopropyl-6,8-difluoro-7 (4-methylpiperazin- 1 -yl)-4-oxo- 1 ,4- dihydroquinolin -3-carboxylic acid-5-yl )- 1 ,9-diaminononane; 6) N,N'-bis-(l -cyclopropyl-6,8-difluoro-7-ι (4-methylpiperazin- 1 -yl)-4-oxo- 1 ,4- dihydroquinolin -3-carboxylic acid-5-yl )- 1 , 13-diamino-4,7, 10-trioxotrisdecane; 7) N,N'-bis-(l -cyclopropyl-6,8-difluoro-7-ι (4-methylpiperazin- 1 -yl)-4-oxo-l ,4- dihydroquinolin -3-carboxylic acid-5-yl )-l ,3-bis(aminomethyl)benzene; 8) N,N'-bis-( 1 -cyclopropyl-6,8-difluoro-7 (4-methylpiperazin- 1 -yl)-4-oxo- 1 ,4- dihydroquinolin -3-carboxylic acid-5-yl )-l ,4-bis(aminomethyl)benzene; 9) N,N'-bis-( 1 -cyclopropyl-6,8-difluoro-7 (4-methylpiperazin- 1 -yl)-4-oxo- 1 ,4- dihydroquinolin -3-carboxylic acid-5-yl )-l ,5-diamino-3-oxopentane. C. Similarly, by optionally replacing the compound of Formula II in 1 A above with other compounds of Formula II and optionally replacing 1,3-diaminopropane with other appropriate diamines, other compounds of Formula I are prepared. EXAMPLE 2 Preparation of Compounds of Formula I A. Preparation of a Compound of Formula I. in which L is a compound of Formula II in which R 2 , R^ 1 and R 8 are Hydrogen, R is Carboxy. R is Fluorine, and R 7 is 1- Piperazinyl, linked via the 1 -Position by 1.2-Dimethylphenyl, p is 2 and q is 1 1. Preparation of a Compound of Formula (2) in which R is Ethyl, R 5 and R 8 are Hydrogen, and R 6 and R 7 are Fluorine 0.3 g (1.2 mmol) of 6,7-difluoro-4-oxo-l,4-dihydroquinoline-3-carboxylic acid ethyl ester, a compound of formula (1) prepared as shown in J. Med. Chem. 1996, 39, 436-445, was mixed with 7 mL of DMF, 0.052 g (1.32 mmol) of 60% NaH was added, and the mixture was stirred under N 2 for 10 minutes at room temperature and then 3 minutes at 80°C, to produce a clear solution. The solution was cooled to room temperature and 0.14 g (0.54 mmol) of 1 ,2-bisbenzyl bromide was added. The mixture was stirred at 85 °C for 18 hours. The reaction was then cooled and precipitated from a 2:1 mixture of diethyl ether and ethyl acetate. The resulting solid was collected by filtration and washed with ether to obtain 0.42 g crude product of formula (2), i.e. 1,2-bis- (6,7-difluoro-4-oxo-l,4-dihydroquinoline-3-carboxylic acid ethyl ester- 1-meth-l-yl)- benzene, which was used directly in the next reaction. 2. Preparation of a Compound of Formula (2) in which R is Ethyl, R 5 and R 8 are Hydrogen, and R 6 is Fluorine, and R 7 is 1 -Piperazinyl 0.16 g (0.3 mmol) of the crude product from 1 above was mixed with 0.068 g (0.9 mmol) of piperazine in 3 mL of DMF. The mixture was heated in an 85°C oil bath for 2 hours. The mixture was cooled and poured into ethyl acetate. The solid was collected, washed with ether, and dried to obtain 0.15 g of crude l,2-bis-(6-fluoro-7-(piperazin-l- yl)-4-oxo-l,4-dihydroquinoline-3-carboxylic acid ethyl ester- 1-yl)- 1 ,2-dimethylbenzene, which was used directlv in the next reaction. 3. Preparation of a Compound of Formula I 0.05 g of the crude product from 2. above was mixed with 5 mL of 2N NaOH and heated for 1.5 hours in a 100°C oil bath. The reaction was then cooled and acidified with cone. HCl. 2 mL of acetonitrile was added to solubilize the precipitate and the solution was purified by prep. HPLC using a 5-40%> acetonitrile/0.1%aqueous TFA gradient over 40 min. Pure product fractions were determined by LC/MS and were lyophilized to yield 19 mgs (0.02 mmol) of crude l,2-bis-(6-fluoro-7-(piperazin-l-yl)-4-oxo-l,4- dihydroquinoline-3 -carboxylic acid-l-yl)-1.2-dimethylbenzene, a compound of Formula I as the bis TFA salt. B. Similarly, replacing 1 ,2-bisbenzyl bromide by: 1) l-bromo-2-[2-(2-bromoethoxy))ethoxy]ethane; 2) 1 ,2-dibromoethane; 3) 1 ,4-dibromobutane; 4) 1,5-dibromopentane; 5) 1,6-dibromohexane; 6) 1 ,8-dibromooctane; 7) 1,10-dibromodecane; 8) 1 ,4-bis-(bromomethyl)-benzene; 9) l,3-bis-(bromomethyl)-benzene; and 10) 4, 13-bis-(6-bromohexyl)-(4, 13-diaza- 18-crown-6); the following compounds of Formula I were prepared: 1 ) 1 ,8-bis-(6-fluoro-7-(piperazin-l -yl)-4-oxo-l ,4-dihydroquinoline-3-carboxylic acid- 1 -y l)-3 ,6-dioxooctane; 2) 1.2-bis-(6-fluoro-7-(piperazin- 1 -yl)-4-oxo- 1 ,4-dihydroquinoline-3-carboxylic acid-l-yl)-ethane; 3) l,4-bis-(6-fluoro-7-(piperazin-l-yl)-4-oxo-l,4-dihydroquinoline-3 -carboxylic acid-l-yl)-butane; ) 1 ,5-bis-(6-fluoro-7-(piperazin- 1 -yl)-4-oxo- 1 ,4-dihydroquinoline-3-carboxylic acid-l-yl)-pentane; 5) 1 ,6-bis-(6-fluoro-7-(piperazin- 1 -yl)-4-oxo- 1 ,4-dihydroquinoline-3-carboxylic acid-l-yl)-hexane; 6) l,8-bis-(6-fluoro-7-(piperazin-l-yl)-4-oxo-l,4-dihydroquinoline-3-carboxylic acid-l-yl)-octane; 7) 1,10-bis-(6-fluoro-7-(piperazin- 1 -yl)-4-oxo- 1 ,4-dihydroquinoline-3-carboxylic acid-l-yl)-decane; 8) 1 ,3 -bis-(6-fluoro-7-(piperazin- 1 -y l)-4-oxo- 1 ,4-dihydroquinoline-3 -carboxylic acid- 1 -yl)- 1 ,3-dimethylbenzene; 9) l,4-bis-(6-fluoro-7-(piperazin-l-yl)-4-oxo-l,4-dihydroquinoline-3-carboxylic acid-l-yl)-l ,4-dimethylbenzene; and 10) 4, 13-bis-[6-fluoro-7-(piperazin- 1 -yl)-4-oxo- 1 ,4-dihydroquinoline-3 -carboxylic acid- 1 -(hex-6-yl)]-(4, 13-diaza- 18-crown-6). C. Similarly, optionally replacing the compound of Formula II in 2A above with other compounds of Formula II and optionally replacing 1 ,2-bisbenzyl bromide by other dihalides, other compounds of Formula I are prepared. EXAMPLE 3 Preparation of Compounds of Formula I Preparation of a Compound of Formula I in which L is a compound of Formula II in which R 1 is cyclopropyl. R 2 , R 3 and R 8 are Hydrogen, R 3 is Carboxy, R 6 is Fluorine, and R is 1 -Piperazinyl. linked via the Sidechain at the 4-Piperazinyl Position by 1,2- Dimethylphenyl, p is 2 and q is 1 1. 1.7 g (6.4 mmol) of 1 -cyclopropyl-6,7-difluoro-4-oxo- 1 ,4-dihydroquinoline-3- carboxylic acid (a compound of Formula II), 2.7 g (19.2 mmol) of K C0 3 , and 1.7 mL (12.8 mmol) of 4-methoxy benzyl chloride was heated in 20 mL of DMF at 85°C for 2hours. The reaction mixture was cooled and poured into 400 mL of stirring water. The resulting precipitate was filtered and washed with 100 mL of water to yield 2.1 g of 1- cyclopropyl-6.7-difluoro-4-oxo-l,4-dihydroquinoline-3-carboxylic acid 4-methoxybenzyl ester as a solid. After drying, this solid was used directly in the next step. EXAMPLE 4 Preparation of Compounds of Formula I A. Preparation of a Compound of Formula I in which L is a compound of Formula II in which R 1 is Cyclopropyl, R 2 is Hydrogen, R 3 is Carboxy, R 6 and R 8 are Fluorine, and R 7 is 1 -Piperazinyl, p is 2 and q is 1, linked via the 5-Position by a linker 1). Preparation of a Compound of Formula (27) A capsule of Argogel MBCHO resin (1 cap=0.157g; 0.35-0.45 mmol/g) was suspended in 3 mL of 1 ,2-dichoroethane in a 5 mL reaction vessel in an Argonaut Quest 210 Organic Synthesizer. The resin was agitated for 5 minutes and the solvent drained. Sodium triacetoxyborohydride (0.46 mmol; 7eq based on resin) was weighed into each of the reaction vessels and 3 mL of dichloroethane was added and the resulting mixture agitated for 5 minutes. A diamine (5 equivalent based on resin), (see the Table) was added, and. the resin was agitated overnight at room temperature. The solvent and reactants were washed away by successive washings of methanol (x3), dichloromethane (x3) and 10%> DIPEA in dichloromethane (xl). Prior to the acylation of step 2 the resin was washed once with N-methylpyrrolidine (NMP). 1) Preparation of a Compound of Formula (28) in which Q is 2 Fmoc beta-Alanine or Fmoc-glycine (0.39 mmol; 6 equivalent based on resin) was dissolved in 3 mL of NMP. HOAT (0.19 mmol; 3 equivalent based on resin) and HATU (0.2 mmol: 3 equivalent based on resin) with diisopropylefhylamine (0.47 mmol; 7.2 equivalent based on resin). The solutions were activated for 5 minutes before addition to the diamine-substituted resin, and then added in equal portions to each reaction well. The resin mixture was agitated for 3 hours at room temperature. The resin was washed with NMP (x3) and DMF (x3). The Fmoc group was removed with 20%> piperidine in DMF (2x15 minute). The piperidine was washed away with DMF (x3), methanol (x3) and dichloromethane (x3). Prior to acylation with the quinolone the resin was washed with NMP (xl). 2) Preparation of a Compound of Formula I l-cyclopropyl-7-(4-methylpiperazine)-5,6,8-trifluoro-4-oxo-l,4- dihydroquinoline-3 -carboxylic acid (0.4 mmol; 6 equivalent based on resin) was dissolved in 3 mL of DMPU and added to the product of step 1. Disopropylethylamine (1.55 mmol; 4 equivalent based on quinolone) was added and the resin mixture shaken at 85°C overnight. The excess quinolone was washed away with successive washings of DMPU (xl), DMF (x3), methanol (x3) and DCM (x3). The resin was completely dried by passing a stream on nitrogen gas through the reaction vessels for 2 hours prior to cleavage. Cleavage form the resin was performed on all vessels using 5 mL of 95% TFA/5% water for 5 hours at 50°C. The cleavage solution was then drained off into 40 mL EPA vials and the resin was washed with an additional 3 mL of TFA. The TFA was removed using a Savant SpeedVac evaporator to yield the crude product (see Table 2). The compounds were then subjected to preparatory LC/MS purification. Analytical HPLC and MS confirmed the identity of the collected fractions. Thus obtained was a compound of Formula I wherein L is a compound of Formula II in which R 1 is cyclopropyl, R 2 is Hydrogen, R 3 is Carboxy, R 6 and R 8 are Fluorine, and R 7 is 1- Piperazinyl, p is 2 and q is 1, linked via the 5-Position by a linker of the formula: in which both Q are either methylene or ethylene, and the shaded ball represents the "core" of a diamine, as detailed in the Table below. B. Following the above procedure, varying the diamine and using Fmoc beta-alanine or Fmoc glycine, the following bivalent compounds of Formula I were prepared, in which the ligand is l-cyclopropyl-7-(4-methylpiperazine)-6,8-diifluoro-4-oxo-l,4- dihydroquinoline-3-carboxylic acid linked at the 5-position by a linker of the formula: Q and the shaded ball are as defined above. EXAMPLE 5 Preparation of Compounds of Formula I A. Preparation of a Compound of Formula I in which L is a compound of Formula II in which R is Cyclopropyl, R 2 is Hydrogen, R 3 is Carboxy, R^ and R 8 are Hydrogen, R is Fluorine, and R is 1 -Piperazinyl, p is 2 and q is 1, linked via the -NH-Group of the 7- Piperazinyl by -CH 2 -C(0)-NH-W-NH-C(Q)-CH 2 - (in which W is equivalent to the shaded ball as defined above) 1). Preparation of a Compound of Formula (29) A capsule of Argogel MBCHO resin (1 cap=0.157g; 0.35-0.45 mmol/g) was suspended in 3 mL of 1 ,2-dichoroethane in a 5 mL reaction vessel. The resin was agitated for 5 minutes and the solvent drained. Sodium triacetoxyborohydride (0.46 mmol; 7eq based on resin) and 3mL of dichloromethane was added into each of the reaction vessels and agitated for 5 minutes. A diamine (5 equivalent based on resin), (see Table 1) was added, and the resin was agitated overnight at room temperature. The solvent and reactants were washed away by successive washings of methanol (x3), dichloromethane (x3) and 10%> DIPEA in dichloromethane (xl). Prior to performing the next step, the resin was washed once with NMP. 2) Preparation of a Compound of Formula (30) 4-Fmoc-piperazin-l-ylacetic acid hydrate (0.39 mmol; 6 equivalent based on the resin substitution) was dissolved in 3 mL of NMP. HOAT (0.19 mmol; 3 equivalent based on resin) and HATU (0.2 mmol; 3 equivalent based on resin) were added along with DIPEA (0.47 mmol; 7.2 equivalent based on resin). The solution was activated for 5 minutes before addition to the diamine-substituted resin obtained in step 2). The mixture was agitated for 3 hours at room temperature, and then the acid was washed away with NMP (x3) and DMF (x3). The Fmoc group was removed with 20%) piperidine in DMF. The piperidine was washed away with DMF (x3), methanol (x3) and DCM (x3). Prior to performing the next step, the resin was washed with NMP (xl). 3) Preparation of a Compound of Formula I 1 -Cyclopropyl-6,7-difluoro-4-oxo- 1 ,4-dihydroquinoline-3-carboxylic acid (4- methoxybenyl) ester (0.4 mmol; 6 equivalent based on resin substitution) was suspended in 3 mL of DMPU and added to the resin. DIPEA (1.55 mmol; 4 equivalent based on quinolone) was added and the resin mixture shaken at 115°C overnight. The excess quinolone was washed away with successive washings of DMPU (xl), DMF (x3), methanol (x3) and DCM (x3). The resin was completely dried by passing a stream on nitrogen gas through the reaction vessels for 2 hours prior to cleavage. Cleavage was performed on all vessels using 5 mL of 95%> TFA/5% water for 5 hours at 50°C. The cleavage solution was then drained off into 40 mL EPA vials and the resin was washed with an additional 3 mL of TFA. The TFA was removed using a Savant SpeedVac evaporator. The compounds were then subjected to preparatory LC/MS purification using acetonitrile/water with 0.1 % TFA gradients. Collected fractions were concentrated using a SpeedVac (Table 2). Analytical HPLC and MS confirmed the identity of the collected fractions. B. Following the above procedure, varying the diamine, the following bivalent compounds of Formula I were prepared, in which the ligand is 1 -cyclopropyl-6-fluoro-7- (piperazin-l-yl)-4-oxo-l,4-dihydroquinoline-3 -carboxy lie acid, linked at the -NH-group of the 7-piperazinyl moiety by -CH 2 -C(0)-NH-W-NH-C(0)-CH 2 -, where W represents a linker "core". EXAMPLE 6 This example illustrates the preparation of a representative pharmaceutical formulation for oral administration containing a multibinding compound of the invention. Ingredients Quantity per tablet, mgs. Active Compound 200 Lactose, spray -dried 148 Magnesium stearate 2 The above ingredients are mixed and introduced into a hard-shell gelatin capsule. Other multibinding compounds of the invention can be used as the active compound in the preparation of the orally administrable formulations of this example. EXAMPLE 7 This example illustrates the preparation of another representative pharmaceutical formulation for oral administration containing a multibinding compound of the invention. Ingredients Quantity per tablet, mgs. Active Compound 400 Cornstarch 50 Lactose 145 Magnesium stearate 5 The above ingredients are mixed intimately and pressed into single scored tablets. Other multibinding compounds of the invention can be used as the active compound in the preparation of the orally administrable formulations of this example. EXAMPLE 8 This example illustrates the preparation of a representative pharmaceutical formulation containing a multibinding compound of the invention An oral suspension is prepared having the following composition. Ingredients Active Compound 1.0 g Fumaric acid 0.5 g Sodium chloride 2.0 g Methyl paraben 0.1 g Granulated sugar 25.5 g Sorbitol (70% solution) 12.85 g Veegum K (Vanderbilt Co.) 1.0 g Flavoring 0.035 ml Colorings 0.5 mg Distilled water q.s. to 100 ml Other multibinding compounds of the invention can be used as the active compound in the preparation of the orally administrable formulations of this example. EXAMPLE 9 This example illustrates the preparation of a representative pharmaceutical formulation containing a multibinding compound of the invention. An injectable preparation buffered to a pH of 4 is prepared having the following composition: Ingredients Active Compound 0.2 g Sodium Acetate Buffer Solution (0.4 M) 2.0 ml HCL (IN) q.s. to pH 4 Water (distilled, sterile) q.s. to 20 ml Other multibinding compounds of the invention can be used as the active compound in the preparation of the injectable formulations of this example. EXAMPLE 10 This example illustrates the preparation of a representative pharmaceutical formulation for injection containing a multibinding compound of the invention. A reconstituted solution is prepared by adding 20 ml of sterile water to lg of the compound of Formula I. Before use, the solution is then diluted with 200 ml of an intravenous fluid that is compatible with the compound of Formula I. Such fluids are chosen from 5%> dextrose solution, 0.9% sodium chloride, or a mixture of 5% dextrose and 0.9%) sodium chloride. Other examples are lactated Ringer's injection, lactated Ringer's plus 5%> dextrose injection, Normosol-M and 5% dextrose, Isolyte E, and acylated Ringer's injection Other multibinding compounds of the invention can be used as the active compound in the preparation of the injectable formulations of this example. EXAMPLE 1 1 This example illustrates the preparation of a representative pharmaceutical formulation for topical application containing a multibinding compound of the invention. Ingredients grams Active compound 0.2-10 Span 60 2 Tween 60 2 Mineral oil 5 Petrolatum 10 Methyl paraben 0.15 Propyl paraben 0.05 BHA (butylated hydroxy anisole) 0.01 Water q.s. to 100 All of the above ingredients, except water, are combined and heated to 60°C with stirring. A sufficient quantity of water at 60°C is then added with vigorous stirring to emulsify the ingredients, and water then added q.s. 100 g. Other multibinding compounds of the invention can be used as the active compound in the preparation of topical formulations of this example. EXAMPLE 12 This example illustrates the preparation of a representative pharmaceutical formulation containing a multibinding compound of the invention. A suppository totaling 2.5 grams is prepared having the following composition: Ingredients Active Compound 500 mg Witepsol H-15 * balance ( triglycerides of saturated vegetable fatty acid; a product of Riches-Nelson, Inc., New York, N.Y.) Other multibinding compounds of the invention can be used as the active compound in the preparation of the suppository formulations of this example. EXAMPLE 13 DETERMINATION OF ANTIBACTERIAL ACTIVITY In Vitro Determination of Antibacterial Activity by DNA Biosynthesis Assay A. Preparation of Cells E. Coli H560 was grown in 50 mlAB3 medium in a shaking water bath at 37°C, using a 5% inoculum from an overnight culture, until OD 560 was between 0.5-0.7. The cells were harvested by centrifugation at 8000 rpm for 5 minutes, and the pellet washed with 5 ml of 20 mM HEPES, pH 8.0. The pellet was resuspended in 2 ml of 20 mM HEPES, pH 8.0, and the suspension transferred to a glass tube (13x100 mm). Toluene (20 μl) was added, and the mixture shaken by hand for 5 minutes at room temperature. The reaction was terminated by the addition of 3 ml of 20 mM HEPES, pH 8.0, and the mixture centrifuged at 4000 rpm for 5 minutes. The pellet was washed twice with 5 ml of 20 mM HEPES, pH 8.0, and the pellet was resuspended in 1.6 ml of 20 mM HEPES, pH 8.0. Reagent Mixtures Reagent Mixture without ATP : 3 μl 133 mM DTT in 20 mM HEPES, pH 8.0 8 μl 0.25 M Mg(OAc) 2 in 20 mM HEPES, pH 8.0 5 μl 4 M KCl in 20 mM HEPES, pH 8.0 4 μl 5 mM NAD in 20 mM HEPES, pH 8.0 4 μl 1 mM dATP in 20 mM HEPES, pH 8.0 4 μl 1 mM dCTP in 20 mM HEPES, pH 8.0 4 μl 1 mM dGTP in 20 mM HEPES, pH 8.0 8 μl 20 mM HEPES, pH 8.0 8 μl [ 3 H] TTP Mix Reagent Mixture with ATP: 15 μl 133 mM DTT in 20 mM HEPES, pH 8.0 40 μl 50 mM ATP in 20 mM HEPES, pH 8.0 40 μl 0.25 M Mg(OAc) 2 in 20 mM HEPES, pH 8.0 25 μl 4 M KCl in 20 mM HEPES, pH 8.0 20 μl 5 mM NAD in 20 mM HEPES, pH 8.0 20 μl 1 mM dATP in 20 mM HEPES, pH 8.0 20 μl 1 mM dCTP in 20 mM HEPES, pH 8.0 20 μl 1 mM dGTP in 20 mM HEPES, pH 8.0 40 μl [ 3 H] TTP Mix [ 3 H] TTP Mix: 40 μl 20 mM HEPES, pH 8.0 5 μl 5 mM TTP in 20 mM HEPES, pH 8.0 5 μl [ 3 H] TTP (Amersham; specific activity = 40-60 Ci/mmol; 1 μl should contain approx.20, 000-25,000 CPM Samples (in duplicate) Blank (boiled cells, or cells + TCA, or buffer with no cells) Control without ATP Control with ATP Test compounds (all with ATP) Test compounds - final concentrations 0.2, 1, 5, 20, 100 40 μg/ml. Assay Combined in a 6x50 mm test tube were: 5 μl of the test compound; 8 μl of the reagent mixture; and 14 μl of cells. The mixture was incubated at 30°C for 30 minutes, and the reaction then terminated with 5 μl of 10% TCA. Each reaction mixture was spotted onto a 2.3 cm diameter 3 mm filter paper disc cut in half, placed upon a tile. Each tube was rinsed with 20 μl of distilled water and spotted on the corresponding disc. The discs were air dried for 20 minutes, then washed 2x30 minutes in 5% TCA, followed by a 30 minute wash in 95% ethanol at 0°C. The discs were dried on a piece of aluminum foil under a heat lamp for 15 minutes, and the scintillation count carried out in 5 ml of Aquasol. The compounds of the invention were active in the above tests. While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims appended hereto. Table of Linkers

Claims: IT IS CLAIMED: 1. A multibinding compound of the formula: (L) p X q Formula I in which L is a ligand that may be the same or different at each occurrence: X is a linker that may be the same or different at each occurrence; p is an integer of 2-10: and q is an integer of 1 -20. each of said ligands compromising a ligand domain capable of inhibiting bacterial Type II DNA topoisomerase; or a pharmaceutically acceptable salt thereof. 2. A compound of claim 1. wherein L is a ligand of the formula: wherein: R is hydrogen, lower alkyl, lower alkoxy. lower haloalkyl, cycloalkyl. cycloalkylalkyl. alkylamino. aryl. heteroaryl. or heterocyclo. or R 1 is a covalent bond that links the ligand to a linker: R 2 is hydrogen, lower alkyl: lower alkoxy. or halo, or R : is a covalent bond that links the ligand to a linker; R J is -COOR 4 , in which R 4 is hydrogen or lower alkyl: or R 2 and R J when taken together with the carbons to which they are attached represent a group of the formula; in which R 9 is hydrogen or lower alkyl. or R 9 is a covalent bond that links the ligand to a linker; R "^ is hydrogen, lower alkyl. lower alkoxy. hydroxy. halo, cycloalkyl. cycloalkylalkyl. amino. alkylamino. aryl. heteroaryl. or heterocyclo. or R is a covalent bond that links the ligand to a linker; Y is -N- or -CR 6 -. in which R 6 is hydrogen, lower alkyl. hydroxy. lower alkoxy, halo. cycloalkyl, cycloalkylalkyl, alkylamino, aryl. heteroaryl. or heterocyclo, or R 6 is a covalent bond that links the ligand to a linker; R is hydrogen, lower alkyl. lower alkoxy. hydroxy. halo, cycloalkyl. cycloalkylalkyl. alkylamino. aryl. heteroaπ. 1. or heterocyclo. or R is a covalent bond that links the ligand to a linker, or R is a covalent bond that links a 7-piperazinyl group of the ligand to a linker. Z is -N- or -CR -, in which R is hydrogen, lower alkyl. or halo, or R is a covalent bond that links the ligand to a linker: or R and R when taken together represent a group of the formula 0-W-O; or R and R when taken together represent a group of the formula -0-W-; in which W is lower alkylene: or a pharmaceutically acceptable salt thereof. 3. The compound of claim 2. wherein the ligands is chosen from nalidixic acid, piromidic acid, pipermidic acid, oxolinic acid, cinoxacin. miloxacin. rosoxacin. norfloxacin. ciprofloxacin. ofloxacin. enoxacin, pefloxacin. flerofloxacin. flumequine. lomefloxacin. temafloxacin. sparfloxacin. norfloxacin. ciprofloxacin. and ofloxacin. 4. The compound of claim 2. wherein p is 2. and q is 1. 5. The compound of claim 4. wherein both ligands are the same, in which R 1 is a covalent bond that links the ligand to a linker. R 2 . R; and R 8 are hydrogen. R J is carboxy, R 6 is fluorine, and R 7 is piperazin-1-yl. 6. The compound of claim 5. wherein the linker is decylene. namely l , 10-bis-(6- fluoro-7-(piperazin- 1 -yl)-4-oxo- 1 ,4-dihydroquinoline-3-carboxylic acid- 1 -yl)-decane. 7. The compound of claim 4. wherein both ligands are the same, in which R ? is a covalent bond that links the ligand to a linker. R 1 is cyclopropyl. R ~ is hydrogen, R is carboxy. R 6 and R 8 are fluorine, and R 7 is piperazin- 1 -yl. 8. The compound of claim 7. wherein the linker is 1.9-diaminononane, namely N.N ' - bis-(l -cyclopropyl-6.8-difluoro-7-(4-methylpiperazin-l -yl)-4-oxo-1.4-dihydroquinolin - 3-carboxylic acid-5-yl)- 1 ,9-diaminononane. 8. The compound of claim 6. wherein the linker is: -NH-CH 2 -C(0)NH-(CH 2 ) 2 -0-(CH 2 ) 2 -NHC(0)-CH 2 -NH-. 9. The compound of claim 4. wherein both ligands are the same, in which R is cyclopropyl. R 2 is hydrogen. R " ' is carboxy. R 6 and R 8 are fluorine, and R is piperazinyl. in which the ligand is attached to a linker via the 4-piperazinyl position. The compound of claim 9. wherein the linker is: -CH 2 -C(0)-CH 2 NH-(CH 2 ) 2 -0-(CH 2 ) 2 -NHCH 2 -C(0)-CH 2 1 1 . The compound of claim 4. wherein both ligands are the same, in which R is cyclopropyl. R 2 and R 3 when taken together with the carbons to which they are attached represent a group of the formula: in which R 9 is a covalent bond that links the ligand to a linker; R 5 , R 6 and R 8 are fluorine, and R is piperazin-1-yl. 12. The compound of claim 1 1. wherein the linker is alkylene. 13. The compound of claim 12. wherein the linker is decylene. 14. The compound of claim 4, wherein both ligands are the same, in which R is a covalent bond that links the ligand to a linker, R 1 is cyclopropyl. R ~ is hydrogen. R J is carboxy. R 6 and R 8 are fluorine, and R is piperazin-1 -yl. 15. The compound of claim 14. wherein the linker is -0-(CH 2 )ιo-0-. 16. A method for treating a pathologic condition which is alleviated by treatment with an antibacterial agent, comprising administering to a subject in need of such treatment a therapeutically effective amount of a multibinding compound; wherein said multibinding compound comprises a compound of the formula: ( ) p X q Formula I in which L is a ligand that may be the same or different at each occurrence; X is a linker that may be the same or different at each occurrence: p is an integer of 2-10: and q is an integer of 1 -20. each of said ligands compromising a ligand domain capable of inhibiting bacterial Type II DNA topoisomerase: or a pharmaceutically acceptable salt thereof. 17. A pharmaceutical composition comprising a therapeutically effective amount of one or more compounds of the formula: ( ) P X q Formula I in which L is a ligand that may be the same or different at each occurrence; X is a linker that may be the same or different at each occurrence; p is an integer of 2-10; and q is an integer of 1 -20. each of said ligands compromising a ligand domain capable of inhibiting bacterial Type II DNA topoisomerase; or a pharmaceutically acceptable salt thereof: admixed with at least one pharmaceutically acceptable excipient. 18. A method for identifying multimeric ligand compounds that possess multibinding properties with respect to bacterial Type II DNA topoisomerase: which method comprises: identifying a ligand or mixture of ligands capable of binding to bacterial Type II DNA topoisomerase; and having at least one chemically reactive functional group: (a) identifying a library of linkers wherein each linker in said library comprises at least two functional groups having complementary chemical activity to at least one of the ligand functional groups: (b) preparing a multimeric ligand compound by combining the ligand or ligands identified in step (a) with the library of linkers identified in step (b) under conditions sufficient to form covalent linkages between the complementary functional groups of the ligand or ligands and the linker: and (c) assaying the multimeric ligand compound library produced in step (c) and selecting multibinding agents based upon the ability of said library to bind to bacterial Type II DNA topoisomerase; 19. The method of claim 18, wherein said linker chain length ranges from about 2 to IOOA. 20 The method of claim 18. wherein said multimeric ligand compound comprises hgands that are the same 21 The method of claim 18. wherein said multimeric ligand compound comprises ligands that are different 22 A library of multimeric ligand compounds that ma possess multibinding properties related to a bacterial Tv pe II DNA topoisomerase. which method comprises. (a) identifying a ligand or mixture of ligands capable of binding to bacterial Ty pe II DNA topoisomerase, and hav ing at least one chemically reactiv e functional group. (b) identify ing a librarv of linkers wherein each linker in said librarv comprises at least two functional groups having complementary chemical activ ity to at least one of the ligand functional groups, and (a) preparing a multimeric ligand compound by combining the ligand or ligands identified in step (a) with the librarv of linkers identified in step (b) under conditions sufficient to form cov alent linkages between the complementary functional groups of the ligand or hgands and the linker 23 The library according to claim 22. wherein said librarv of linkers is selected from the group comprising flexible linkers, rigid linkers hv drophobic linkers, hy drophilic linkers, linkers of different geometry , acidic linkers, basic linkers, and amphiphihc linkers 24 The librarv according to claim 22. wherein each of said linkers in said linker librarv comprise linkers of different chain length and Or having different complementarv reactive groups 25 The librarv according to claim 22 wherein said linker chain length ranges from about 2 to 100A 26. The library according to claim 22. wherein said multimeric ligand compound is homomeric. 27. The library according to claim 22. wherein said multimeric ligand compound is heteromeric.

Inventors: FATHEREE PAUL, GRIFFIN JOHN H, JUDICE J KEVIN, PACE JOHN L, FATHEREE, PAUL, GRIFFIN, JOHN, H., JUDICE, J., KEVIN, PACE, JOHN, L.
Applicants: ADVANCED MEDICINE INC, FATHEREE PAUL, GRIFFIN JOHN H, JUDICE J KEVIN, PACE JOHN L, ADVANCED MEDICINE, INC., FATHEREE, PAUL, GRIFFIN, JOHN, H., JUDICE, J., KEVIN, PACE, JOHN, L.
Application year: 1999
Main classification: A61K38
IPC codes: A01N57, A61K31, A61K38, A61K39, A61K47, A61K51, A61P31, A61P43, C07B61, C07C233, C07C237, C07C271, C07C275, C07C335, C07D207, C07D211, C07D215, C07D233, C07D235, C07D263, C07D265, C07D401, C07D405, C07D413, C07D453, C07D471, C07D473, C07D475, C07D477, C07D487, C07D493, C07D495, C07D498, C07D499, C07D501, C07D519, C07H15, C07H17, C07H19, C07K2, C07K4, C12N9, C12P19, C12Q1, C40B30, C40B40, G01N33, G01N37