MODIFICATION OF BIOLOGICAL TARGETING GROUPS FOR THE TREATMENT OF CANCER

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claim priority to United States provisional patent application serial number 60/915,070, filed April 30, 2007, the entirety of which is hereby incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to the field of polymer chemistry and more particularly to encapsulated contrast agents and uses thereof.

BACKGROUND OF THE INVENTION

[0003] The development of new therapeutic agents has dramatically improved the quality of life and survival rate of patients suffering from a variety of disorders. However, drug delivery innovations are needed to improve the success rate of these treatments. Specifically, delivery systems are still needed which effectively minimize premature excretion and/or metabolism of therapeutic agents and deliver these agents specifically to diseased cells thereby reducing their toxicity to healthy cells.

[0004] Rationally-designed, nanoscopic drug carriers, or "nanovectors," offer a promising approach to achieving these goals due to their inherent ability to overcome many biological barriers. Moreover, their multi-functionality permits the incorporation of cell-targeting groups, diagnostic agents, and a multitude of drugs in a single delivery system. Polymer micelles, formed by the molecular assembly of functional, amphiphilic block copolymers, represent one notable type of multifunctional nanovector.

[0005] Polymer micelles are particularly attractive due to their ability to deliver large payloads of a variety of drugs (e.g. small molecule, proteins, and DNA/RNA therapeutics), their improved in vivo stability as compared to other colloidal carriers (e.g. liposomes), and their nanoscopic size which allows for passive accumulation in diseased tissues, such as solid tumors, by the enhanced permeation and retention (EPR) effect. Using appropriate surface functionality, polymer micelles are further decorated with cell-targeting groups and permeation enhancers that

can actively target diseased cells and aid in cellular entry, resulting in improved cell-specific delivery.

[0006] The ability to target the nanoparticles is of importance in allowing for specific imaging of unhealthy cells, e.g. tumors. In order to accomplish this several groups have shown that over expressed receptors can be used as targeting groups. Examples of these targeting groups include Folate, Her-2 peptide, etc. Typically, conjugation reactions are carried out using the primary amine functionality on proteins (e.g. lysine or protein end-group). Because most proteins contain a multitude of lysines and arginines, such conjugation occurs uncontrollably at multiple sites on the protein. This is particularly problematic when lysines or arginines are located around the active site of an enzyme or other biomolecule. Moreover, the attachment of targeting units directly to the nanoparticle surface through ligand attachment include the fact that this bonding is not permanent. The ligands have the tendency to debond from the nanoparticle surface, especially as the nanoparticles are diluted. Thus, it would be advantageous to provide targeting groups that are readily conjugated to a nanoparticle, or other biologically relevant material, in a manner that is sufficiently stable for targeted delivery.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE INVENTION

1. General Description:

[0007] According to one embodiment, the present invention provides a "click- functionalized" targeting group. As used herein, the term "click-functionalized" means that the targeting group comprises a functionality suitable for click chemistry. Click chemistry is a popular method of bioconjugation due to its high reactivity and selectivity, even in biological media. See KoIb, H.C.; Finn, M.G.; Sharpless, K.B. Angew. Chem. Int. Ed. 2001, 40, 2004-2021; and Wang, Q.; Chan, T. R.; Hilgraf, R.; Fokin, V. V.; Sharpless, K. B.; Finn, M. G. J. Am. Chem. Soc. 2003, 125, 3192-3193. In addition, currently available recombinant techniques permit the introduction of azides and alkyne-bearing non-canonical amino acids into proteins, cells, viruses, bacteria, and other biological entities that consist of or display proteins. See Link, A. J.; Vink, M. K. S.; Tirrell, D. A. J. Am. Chem. Soc. 2004, 126, 10598-10602; Deiters, A.; Cropp, T. A.; Mukherji, M.; Chin, J. W.; Anderson, C; Schultz, P. G. J. Am. Chem. Soc. 2003, 125, 11782- 11783.

[0008] In one embodiment, the "click-functionalized" moiety is an acetylene or an acetylene derivative which is capable of undergoing [3+2] cycloaddition reactions with complementary azide -bearing molecules and biomolecules. In another embodiment, the "click-functionalized" functionality is an azide or an azide derivative which is capable of undergoing [3+2] cycloaddition reactions with complementary alkyne-bearing molecules and biomolecules (i.e. click chemistry).

[0009] In another embodiment, the [3+2] cycloaddition reaction of azide or acetylene- bearing nanovectors and complimentary azide or acetylene-bearing biomolecules are transition metal catalyzed. Copper-containing molecules which catalyze the "click" reaction include, but are not limited to, copper wire, copper bromide (CuBr), copper chloride (CuCl), copper sulfate (CuSO ₄ ), copper sulfate pentahydrate (CuSO ₄ *5H ₂ O), copper acetate (Cu ₂ (AcO ₄ ), copper iodide (CuI), [Cu(MeCN) ₄ ](OTf), [Cu(MeCN) ₄ ](PF ₆ ), colloidal copper sources, and immobilized copper sources. Reducing agents as well as organic and inorganic metal-binding ligands can be used in conjunction with metal catalysts and include, but are not limited to, sodium ascorbate, tris(triazolyl)amine ligands, tris(carboxyethyl)phosphine (TCEP), sulfonated bathophenanthroline ligands, and benzimidazole-based ligands. 2. Definitions:

[0010] Compounds of this invention include those described generally above, and are further illustrated by the embodiments, sub-embodiments, and species disclosed herein. As used herein, the following definitions shall apply unless otherwise indicated. For purposes of this invention, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75 ^th Ed. Additionally, general principles of organic chemistry are described in "Organic Chemistry", Thomas Sorrell, University Science Books, Sausalito: 1999, and "March's Advanced Organic Chemistry", 5 ^th Ed., Ed.: Smith, M.B. and March, J., John Wiley & Sons, New York: 2001, the entire contents of which are hereby incorporated by reference.

[0011] As used herein, the term "contrast agent" (also known as "contrast media" and "radiocontrast agents") refers to a compound used to improve the visibility of internal bodily structures during MRI, PET, ultrasound, X-ray, or fluorescence imaging. Such agents include semidonductor materials, such as CdSe, CdS, CdTe, PdSe, CdSe/CdS, CdSe/ZnS, CdS/ZnS, and

CdTe/ZnS. Contrast agents also include magnetic materials such as: Fe, Fe ₂ O ₃ , Fe ₃ O ₄ , MnFe ₂ O ₄ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , Co, Ni, FePt, CoPt, CoO, Fe ₃ Pt, Fe ₂ Pt, Co ₃ Pt, Co ₂ Pt, and FeOOH. [0012] The term "targeting group", as used herein refers to any molecule, macromolecule, or biomacromolecule which selectively binds to receptors that are expressed or over-expressed on specific cell types. Such molecules can be attached to the functionalized end-group of a PEG or drug carrier for cell specific delivery of proteins, viruses, DNA plasmids, oligonucleotides (e.g. siRNA, miRNA, antisense therapeutics, aptamers, etc.), drugs, dyes, and primary or secondary labels which are bound to the opposite PEG end-goup or encapsulated within a drug carrier. Such targeting groups include, but or not limited to monoclonal and polyclonal antibodies (e.g. IgG, IgA, IgM, IgD, IgE antibodies), sugars (e.g. mannose, mannose-6-phosphate, galactose), proteins (e.g. transferrin), oligopeptides (e.g. cyclic and acylic RGD-containing oligopedtides), oligonucleotides (e.g. aptamers), and vitamins (e.g. folate).

[0013] The term "oligopeptide", as used herein refers to any peptide of 2-65 amino acid residues in length. In some embodiments, oligopeptides comprise amino acids with natural amino acid side-chain groups. In some embodiments, oligopeptides comprise amino acids with unnatural amino acid side-chain groups. In certain embodiments, oligopeptides are 2-50 amino acid residues in length. In certain embodiments, oligopeptides are 2-40 amino acid residues in length. In some embodiments, oligopeptides are cyclized variations of the linear sequences. [0014] The term "permeation enhancer", as used herein refers to any molecule, macromolecule, or biomacromolecule which aids in or promotes the permeation of cellular membranes and/or the membranes of intracellular compartments (e.g. endosome, lysosome, etc.) Such molecules can be attached to the functionalized end-group of a PEG or drug carrier to aid in the intracellular and/or cytoplasmic delivery of proteins, viruses, DNA plasmids, oligonucleotides (e.g. siRNA, miRNA, antisense therapeutics, aptamers, etc.), drugs, dyes, and primary or secondary labels which are bound to the opposite PEG end-group or encapsulated within a drug carrier. Such permeation enhancers include, but are not limited to, oligopeptides containing protein transduction domains such as the HIV-I Tat peptide sequence (GRKKRRQRRR), oligoarginine (RRRRRRRRR), or other arginine-rich oligopeptides or macromolecules. Oligopeptides which undergo conformational changes in varying pH environments such oligohistidine (HHHHH) also promote cell entry and endosomal escape.

[0015] As used herein, the term "sequential polymerization", and variations thereof, refers to the method wherein, after a first monomer (e.g. NCA, lactam, or imide) is incorporated into the polymer, thus forming an amino acid "block", a second monomer (e.g. NCA, lactam, or imide) is added to the reaction to form a second amino acid block, which process may be continued in a similar fashion to introduce additional amino acid blocks into the resulting multi-block copolymers.

[0016] As used herein, the term "multiblock copolymer" refers to a polymer comprising one synthetic polymer portion and two or more poly(amino acid) portions. Such multi-block copolymers include those having the format W-X' -X", wherein W is a synthetic polymer portion and X and X' are poly(amino acid) chains or "amino acid blocks". In certain embodiments, the multiblock copolymers of the present invention are triblock copolymers. As described herein, one or more of the amino acid blocks may be "mixed blocks", meaning that these blocks can contain a mixture of amino acid monomers thereby creating multiblock copolymers of the present invention. In some embodiments, the multiblock copolymers of the present invention comprise a mixed amino acid block and are tetrablock copolymers.

[0017] As used herein, the term "triblock copolymer" refers to a polymer comprising one synthetic polymer portion and two poly(amino acid) portions.

[0018] As used herein, the term "tetrablock copolymer" refers to a polymer comprising one synthetic polymer portion and either two poly(amino acid) portions, wherein 1 poly(amino acid) portion is a mixed block or a polymer comprising one synthetic polymer portion and three poly(amino acid) portions.

[0019] As used herein, the term "inner core" as it applies to a micelle of the present invention refers to the center of the micelle formed by the second (i.e., terminal) poly(amino acid) block. In accordance with the present invention, the inner core is not crosslinked. By way of illustration, in a triblock polymer of the format W-X' -X", as described above, the inner core corresponds to the X" block. It is contemplated that the X" block can be a mixed block. [0020] As used herein, the term "outer core" as it applies to a micelle of the present invention refers to the layer formed by the first poly(amino acid) block. The outer core lies between the inner core and the hydrophilic shell. In accordance with the present invention, the outer core is either crosslinkable or is cross-linked. By way of illustration, in a triblock polymer

of the format W-X' -X", as described above, the outer core corresponds to the X' block. It is contemplated that the X' block can be a mixed block.

[0021] As used herein, the terms "drug-loaded" and "encapsulated", and derivatives thereof, are used interchangeably. In accordance with the present invention, a "drug-loaded" micelle refers to a micelle having a drug, or therapeutic agent, situated within the core of the micelle. This is also refered to as a drug, or therapeutic agent, being "encapsulated" within the micelle. [0022] As used herein, the term "polymeric hydrophilic block" refers to a polymer that is not a poly(amino acid) and is hydrophilic in nature. Such hydrophilic polymers are well known in the art and include polyethylene oxide (also referred to as PEO, polyethylene glycol, or PEG), and derivatives thereof, poly(N-vinyl-2-pyrolidone), and derivatives therof, poly(N- isopropylacrylamide), and derivatives thereof, poly(hydroxyethyl acrylate), and derivatives thereof, poly(hydroxylethyl methacrylate), and derivatives thereof, and polymers of N-(I- hydroxypropoyl)methacrylamide (HMPA) and derivatives thereof.

[0023] As used herein, the term "poly(amino acid)" or "amino acid block" refers to a covalently linked amino acid chain wherein each monomer is an amino acid unit. Such amino acid units include natural and unnatural amino acids. In certain embodiments, each amino acid unit is in the L-confϊguration. Such poly(amino acids) include those having suitably protected functional groups. For example, amino acid monomers may have hydroxyl or amino moieties which are optionally protected by a suitable hydroxyl protecting group or a suitable amine protecting group, as appropriate. Such suitable hydroxyl protecting groups and suitable amine protecting groups are described in more detail herein, infra. As used herein, an amino acid block comprises one or more monomers or a set of two or more monomers. In certain embodiments, an amino acid block comprises one or more monomers such that the overall block is hydrophilic. In other embodiments, an amino acid block comprises one or more monomers such that the overall block is hydrophobic. In still other embodiments, amino acid blocks of the present invention include random amino acid blocks (i.e. blocks comprising a mixture of amino acid residues).

[0024] As used herein, the phrase "natural amino acid side-chain group" refers to the side- chain group of any of the 20 amino acids naturally occuring in proteins. Such natural amino acids include the nonpolar, or hydrophobic amino acids, glycine, alanine, valine, leucine isoleucine, methionine, phenylalanine, tryptophan, and proline. Cysteine is sometimes classified

as nonpolar or hydrophobic and other times as polar. Natural amino acids also include polar, or hydrophilic amino acids, such as tyrosine, serine, threonine, aspartic acid (also known as aspartate, when charged), glutamic acid (also known as glutamate, when charged), asparagine, and glutamine. Certain polar, or hydrophilic, amino acids have charged side-chains, depending on environmental pH. Such charged amino acids include lysine, arginine, and histidine. One of ordinary skill in the art would recognize that protection of a polar or hydrophilic amino acid side- chain can render that amino acid nonpolar. For example, a suitably protected tyrosine hydroxyl group can render that tyroine nonpolar and hydrophobic by virtue of protecting the hydroxyl group.

[0025] As used herein, the phrase "unnatural amino acid side-chain group" refers to amino acids not included in the list of 20 amino acids naturally occuring in proteins, as described above. Such amino acids include the D-isomer of any of the 20 naturally occuring amino acids. Unnatural amino acids also include homoserine, ornithine, and thyroxine. Other unnatural amino acids side-chains are well know to one of ordinary skill in the art and include unnatural aliphatic side chains. Other unnatural amino acids include modified amino acids, including those that are N-alkylated, cyclized, phosphorylated, acetylated, amidated, azidylated, labelled, and the like. [0026] As used herein, the phrase "living polymer chain-end" refers to the terminus resulting from a polymerization reaction which maintains the ability to react further with additional monomer or with a polymerization terminator.

[0027] As used herein, the term "termination" refers to attaching a terminal group to a polymer chain-end by the reaction of a living polymer with an appropriate compound. Alternatively, the term "termination" may refer to attaching a terminal group to an amine or hydroxyl end, or derivative thereof, of the polymer chain.

[0028] As used herein, the term "polymerization terminator" is used interchangeably with the term "polymerization terminating agent" and refers to a compound that reacts with a living polymer chain-end to afford a polymer with a terminal group. Alternatively, the term "polymerization terminator" may refer to a compound that reacts with an amine or hydroxyl end, or derivative thereof, of the polymer chain, to afford a polymer with a terminal group. [0029] As used herein, the term "polymerization initiator" refers to a compound, which reacts with, or whose anion or free base form reacts with, the desired monomer in a manner which results in polymerization of that monomer. In certain embodiments, the polymerization

initiator is the compound that reacts with an alkylene oxide to afford a polyalkylene oxide block.

In other embodiments, the polymerization initiator is the amine salt described herein.

[0030] The term "aliphatic" or "aliphatic group", as used herein, denotes a hydrocarbon moiety that may be straight-chain (i.e., unbranched), branched, or cyclic (including fused, bridging, and spiro-fused polycyclic) and may be completely saturated or may contain one or more units of unsaturation, but which is not aromatic. Unless otherwise specified, aliphatic groups contain 1-20 carbon atoms. In some embodiments, aliphatic groups contain 1-10 carbon atoms. In other embodiments, aliphatic groups contain 1-8 carbon atoms. In still other embodiments, aliphatic groups contain 1-6 carbon atoms, and in yet other embodiments aliphatic groups contain 1-4 carbon atoms. Suitable aliphatic groups include, but are not limited to, linear or branched, alkyl, alkenyl, and alkynyl groups, and hybrids thereof such as (cycloalkyl)alkyl,

(cycloalkenyl)alkyl or (cycloalkyl)alkenyl.

[0031] The term "heteroatom" means one or more of oxygen, sulfur, nitrogen, phosphorus, or silicon. This includes any oxidized form of nitrogen, sulfur, phosphorus, or silicon; the quaternized form of any basic nitrogen, or; a substitutable nitrogen of a heterocyclic ring including =N- as in 3,4-dihydro-2H-pyrrolyl, -NH- as in pyrrolidinyl, or =N(R^)- as in N- substituted pyrrolidinyl.

[0032] The term "unsaturated", as used herein, means that a moiety has one or more units of unsaturation.

[0033] The term "aryl" used alone or as part of a larger moiety as in "aralkyl", "aralkoxy", or

"aryloxyalkyl", refers to monocyclic, bicyclic, and tricyclic ring systems having a total of five to fourteen ring members, wherein at least one ring in the system is aromatic and wherein each ring in the system contains three to seven ring members. The term "aryl" may be used interchangeably with the term "aryl ring".

[0034] As described herein, compounds of the invention may contain "optionally substituted" moieties. In general, the term "substituted", whether preceded by the term

"optionally" or not, means that one or more hydrogens of the designated moiety are replaced with a suitable substituent. Unless otherwise indicated, an "optionally substituted" group may have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with more than one substituent selected from a specified group, the substituent may be either the same or different at every position.

Combinations of substituents envisioned by this invention are preferably those that result in the formation of stable or chemically feasible compounds. The term "stable", as used herein, refers to compounds that are not substantially altered when subjected to conditions to allow for their production, detection, and, in certain embodiments, their recovery, purification, and use for one or more of the purposes disclosed herein.

[0035] Suitable monovalent substituents on a substitutable carbon atom of an "optionally substituted" group are independently halogen; -(CH ₂ V ₄ R ⁰ ; -(CH ₂ V ₄ OR ⁰ ; -0-(CH ₂ V ₄ C(O)OR ⁰ ; -(CH ₂ VtCH(OR°) ₂ ; -(CH ₂ V ₄ SR ⁰ ; -(CH ₂ V ₄ Ph, which may be substituted with R°; -(CH ₂ V ₄ O(CH ₂ ViPh which may be substituted with R°; -CH=CHPh, which may be substituted with R°; -NO ₂ ; -CN; -N ₃ ; -(CH ₂ ) ₀ ^N(R°) ₂ ; -(CH ₂ ) _{0 4} N(R°)C(0)R°; -N(R°)C(S)R°; -(CH ₂ ) _{0 4} N(R°)C(O)NR° ₂ ; -N(R°)C(S)NR° ₂ ; -(CH ₂ ) _{0 4} N(R°)C(0)0R°; -N(R°)N(R°)C(O)R°; -N(R ⁰ )N(R°)C(0)NR° ₂ ; -N(R°)N(R°)C(0)0R°; -(CH ₂ ) _{0 4} C(O)R°; -C(S)R ⁰ ; -(CH ₂ ) ₀ ^C(O)OR°; -OC(O)(CH ₂ V ₄ SR-, SC(S)SR ⁰ ; -(CH ₂ ) _{0 4} C(O)NR° ₂ ; -C(S)NR° ₂ ; -C(S)SR ⁰ ; -SC(S)SR ⁰ , -(CH ₂ ) _{0 4} OC(O)NR° ₂ ; -C(0)N(0R°)R°; -C(O)C(O)R ⁰ ; -C(O)CH ₂ C(O)R ⁰ ; -C(NOR°)R°; -(CH ₂ ) ₀ ^SSR°; -S(O) ₂ NR° ₂ ; -(CH ₂ ) _{0 4} S(O)R°; -N(R°)S(O) ₂ NR° ₂ ; -N(R°)S(O) ₂ R°; -N(0R°)R°; -C(NH)NR° ₂ ; -P(O) ₂ R ⁰ ; -P(O)R° ₂ ; -OP(O)R° ₂ ; -OP(O)(OR°) ₂ ; SiR° ₃ ; -(C _L4 straight or branched alkylene)O-N(R°) ₂ ; or -(C _1-4 straight or branched alkylene)C(O)O-N(R°) ₂ , wherein each R ⁰ may be substituted as defined below and is independently hydrogen, Ci_ ₆ aliphatic, -CH ₂ Ph, -0(CH ₂ ViPh, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or, notwithstanding the definition above, two independent occurrences of R ⁰ , taken together with their intervening atom(s), form a 3-12-membered saturated, partially unsaturated, or aryl mono- or bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, which may be substituted as defined below.

[0036] Suitable monovalent substituents on R ⁰ (or the ring formed by taking two independent occurrences of R ⁰ together with their intervening atoms), are independently halogen, -(CH ₂ ) _{0 2} R*, -(haloR*), -(CH ₂ ) _{0 2} 0H, -(CH ₂ ) _{0 2} 0R*, -(CH ₂ ) _{0 2} CH(OR*) ₂ ; -O(haloR'), -CN, -N ₃ , -(CH ₂ )O ₂ C(O)R*, -(CH ₂ )O ₂ C(O)OH, -(CH ₂ ) _{0 2} C(O)OR*, -(CH ₂ V ₂ SR*, -(CH ₂ V ₂ SH, -(CH ₂ )o ₂ NH ₂ , -(CH ₂ V ₂ NHR*, -(CH ₂ ) _{0 2} NR* ₂ , -NO ₂ , -SiR* ₃ , -OSiR* ₃ , -C(O)SR*, -(C _1-4 straight

or branched alkylene)C(O)OR*, or -SSR* wherein each R* is unsubstituted or where preceded by "halo" is substituted only with one or more halogens, and is independently selected from Ci_4 aliphatic, -CH ₂ Ph, -0(CH ₂ )O iPh, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents on a saturated carbon atom of R ⁰ include =0 and =S.

[0037] Suitable divalent substituents on a saturated carbon atom of an "optionally substituted" group include the following: =0, =S, =NNR ^* ₂ , =NNHC(O)R ^* , =NNHC(O)OR ^* , =NNHS(O) ₂ R ^* , =NR ^* , =NOR ^* , -O(C(R ^* ₂ )) _{2 3} O-, or -S(C(R ^* ₂ )) ₂ _ ₃ S-, wherein each independent occurrence of R is selected from hydrogen, Ci_6 aliphatic which may be substituted as defined below, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0- 4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents that are bound to vicinal substitutable carbons of an "optionally substituted" group include: -O(CR ₂ ) ₂ _ ₃ O-, wherein each independent occurrence of R is selected from hydrogen, C i_6 aliphatic which may be substituted as defined below, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. A suitable tetravalent substituent that is bound to vicinal substitutable methylene carbons of an "optionally substituted" group is the dicobalt hexacarbonyl

cluster represented by when depicted with the methylenes which bear it.

[0038] Suitable substituents on the aliphatic group of R include halogen, -R*, -(haloR*), -OH, -OR*, -O(haloR'), -CN, -C(O)OH, -C(O)OR*, -NH ₂ , -NHR*, -NR* ₂ , or -NO ₂ , wherein each R* is unsubstituted or where preceded by "halo" is substituted only with one or more halogens, and is independently Ci_4 aliphatic, -CH ₂ Ph, -O(CH ₂ ) ₀ iPh, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

[0039] Suitable substituents on a substitutable nitrogen of an "optionally substituted" group include -S(O) ₂ R ¹ ; -S(O) ₂ NR^, -C(S)NR^, -C(NH)NR^, or -N(R ^t )S(O) ₂ R ^t ; wherein each R ^f is independently hydrogen, Ci_6 aliphatic which may be substituted as defined below, unsubstituted -OPh, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or, notwithstanding the

definition above, two independent occurrences of R^, taken together with their intervening atom(s) form an unsubstituted 3-12-membered saturated, partially unsaturated, or aryl mono- or bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. [0040] Suitable substituents on the aliphatic group of R^ are independently halogen, -R*, -(haloR*), -OH, -OR*, -O(haloR'), -CN, -C(O)OH, -C(O)OR*, -NH ₂ , -NHR*, -NR* ₂ , or -NO ₂ , wherein each R* is unsubstituted or where preceded by "halo" is substituted only with one or more halogens, and is independently Ci_4 aliphatic, -CH ₂ Ph, -O(CH ₂ ) ₀ iPh, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

[0041] Protected hydroxyl groups are well known in the art and include those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3 ^rd edition, John Wiley & Sons, 1999, the entirety of which is incorporated herein by reference. Examples of suitably protected hydroxyl groups further include, but are not limited to, esters, carbonates, sulfonates allyl ethers, ethers, silyl ethers, alkyl ethers, arylalkyl ethers, and alkoxyalkyl ethers. Examples of suitable esters include formates, acetates, proprionates, pentanoates, crotonates, and benzoates. Specific examples of suitable esters include formate, benzoyl formate, chloroacetate, trifluoroacetate, methoxyacetate, triphenylmethoxyacetate, p-chlorophenoxyacetate, 3-phenylpropionate, 4-oxopentanoate, 4,4-(ethylenedithio)pentanoate, pivaloate

(trimethylacetate), crotonate, 4-methoxy-crotonate, benzoate, p-benylbenzoate, 2,4,6- trimethylbenzoate. Examples of suitable carbonates include 9-fluorenylmethyl, ethyl, 2,2,2- trichloroethyl, 2-(trimethylsilyl)ethyl, 2-(phenylsulfonyl)ethyl, vinyl, allyl, and p-nitrobenzyl carbonate. Examples of suitable silyl ethers include trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, t-butyldiphenylsilyl, triisopropylsilyl ether, and other trialkylsilyl ethers. Examples of suitable alkyl ethers include methyl, benzyl, p-methoxybenzyl, 3,4- dimethoxybenzyl, trityl, t-butyl, and allyl ether, or derivatives thereof. Alkoxyalkyl ethers include acetals such as methoxymethyl, methylthiomethyl, (2-methoxyethoxy)methyl, benzyloxymethyl, beta-(trimethylsilyl)ethoxymethyl, and tetrahydropyran-2-yl ether. Examples of suitable arylalkyl ethers include benzyl, p-methoxybenzyl (MPM), 3,4-dimethoxybenzyl, O- nitrobenzyl, p-nitrobenzyl, p-halobenzyl, 2,6-dichlorobenzyl, p-cyanobenzyl, 2- and 4-picolyl ethers.

[0042] Protected amines are well known in the art and include those described in detail in Greene (1999). Suitable mono-protected amines further include, but are not limited to, aralkylamines, carbamates, allyl amines, amides, and the like. Examples of suitable mono- protected amino moieties include t-butyloxycarbonylamino (-NHBOC), ethyloxycarbonylamino, methyloxycarbonylamino, trichloroethyloxycarbonylamino, allyloxycarbonylamino (-NHAlloc), benzyloxocarbonylamino (-NHCBZ), allylamino, benzylamino (-NHBn), fluorenylmethylcarbonyl (-NHFmoc), formamido, acetamido, chloroacetamido, dichloroacetamido, trichloroacetamido, phenylacetamido, trifluoroacetamido, benzamido, t-butyldiphenylsilyl, and the like. Suitable di-protected amines include amines that are substituted with two substituents independently selected from those described above as mono- protected amines, and further include cyclic imides, such as phthalimide, maleimide, succinimide, and the like. Suitable di-protected amines also include pyrroles and the like, 2,2,5, 5-tetramethyl-[l,2,5]azadisilolidine and the like, and azide.

[0043] Protected aldehydes are well known in the art and include those described in detail in Greene (1999). Suitable protected aldehydes further include, but are not limited to, acyclic acetals, cyclic acetals, hydrazones, imines, and the like. Examples of such groups include dimethyl acetal, diethyl acetal, diisopropyl acetal, dibenzyl acetal, bis(2-nitrobenzyl) acetal, 1,3- dioxanes, 1,3-dioxolanes, semicarbazones, and derivatives thereof.

[0044] Protected carboxylic acids are well known in the art and include those described in detail in Greene (1999). Suitable protected carboxylic acids further include, but are not limited to, optionally substituted Ci_6 aliphatic esters, optionally substituted aryl esters, silyl esters, activated esters, amides, hydrazides, and the like. Examples of such ester groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, benzyl, and phenyl ester, wherein each group is optionally substituted. Additional suitable protected carboxylic acids include oxazolines and ortho esters.

[0045] Protected thiols are well known in the art and include those described in detail in Greene (1999). Suitable protected thiols further include, but are not limited to, disulfides, thioethers, silyl thioethers, thioesters, thiocarbonates, and thiocarbamates, and the like. Examples of such groups include, but are not limited to, alkyl thioethers, benzyl and substituted benzyl thioethers, triphenylmethyl thioethers, and trichloroethoxycarbonyl thioester, to name but a few.

[0046] A "crown ether moiety" is the radical of a crown ether. A crown ether is a monocyclic polyether comprised of repeating units of -CH ₂ CH ₂ O-. Examples of crown ethers include 12-crown-4, 15-crown-5, and 18-crown-6.

[0047] Unless otherwise stated, structures depicted herein are also meant to include all isomeric (e.g., enantiomeric, diastereomeric, and geometric (or conformational)) forms of the structure; for example, the R and S configurations for each asymmetric center, Z and E double bond isomers, and Z and E conformational isomers. Therefore, single stereochemical isomers as well as enantiomeric, diastereomeric, and geometric (or conformational) mixtures of the present compounds are within the scope of the invention. Unless otherwise stated, all tautomeric forms of the compounds of the invention are within the scope of the invention. Additionally, unless otherwise stated, structures depicted herein are also meant to include compounds that differ only in the presence of one or more isotopically enriched atoms. For example, compounds having the present structures except for the replacement of hydrogen by deuterium or tritium, or the replacement of a carbon by a ¹³ C- or ¹⁴ C-enriched carbon are within the scope of this invention. Such compounds are useful, for example, as in neutron scattering experiments, as analytical tools or probes in biological assays.

[0048] As used herein, the term "detectable moiety" is used interchangeably with the term "label" and relates to any moiety capable of being detected (e.g., primary labels and secondary labels). A "detectable moiety" or "label" is the radical of a detectable compound. [0049] "Primary" labels include radioisotope-containing moieties (e.g., moieties that contain ³² P, ³³ P, ³⁵ S, or ¹⁴ C), mass-tags, and fluorescent labels, and are signal-generating reporter groups which can be detected without further modifications.

[0050] Other primary labels include those useful for positron emission tomography including molecules containing radioisotopes (e.g. ¹⁸ F) or ligands with bound radioactive metals (e.g. ⁶² Cu). In other embodiments, primary labels are contrast agents for magnetic resonance imaging such as gadolinium, gadolinium chelates, or iron oxide (e.g Fe ₃ O ₄ and Fe ₂ O ₃ ) particles. Similarly, semiconducting nanoparticles (e.g. cadmium selenide, cadmium sulfide, cadmium telluride) are useful as fluorescent labels. Other metal nanoparticles (e.g colloidal gold) also serve as primary labels.

[0051] "Secondary" labels include moieties such as biotin, or protein antigens, that require the presence of a second compound to produce a detectable signal. For example, in the case of a

biotin label, the second compound may include streptavidin-enzyme conjugates. In the case of an antigen label, the second compound may include an antibody-enzyme conjugate. Additionally, certain fluorescent groups can act as secondary labels by transferring energy to another compound or group in a process of nonradiative fluorescent resonance energy transfer (FRET), causing the second compound or group to then generate the signal that is detected. [0052] Unless otherwise indicated, radioisotope-containing moieties are optionally substituted hydrocarbon groups that contain at least one radioisotope. Unless otherwise indicated, radioisotope-containing moieties contain from 1-40 carbon atoms and one radioisotope. In certain embodiments, radioisotope-containing moieties contain from 1-20 carbon atoms and one radioisotope.

[0053] The terms "fluorescent label", "fluorescent group", "fluorescent compound", "fluorescent dye", and "fluorophore", as used herein, refer to compounds or moieties that absorb light energy at a defined excitation wavelength and emit light energy at a different wavelength. Examples of fluorescent compounds include, but are not limited to: Alexa Fluor dyes (Alexa Fluor 350, Alexa Fluor 488, Alexa Fluor 532, Alexa Fluor 546, Alexa Fluor 568, Alexa Fluor 594, Alexa Fluor 633, Alexa Fluor 660 and Alexa Fluor 680), AMCA, AMCA-S, BODIPY dyes (BODIPY FL, BODIPY R6G, BODIPY TMR, BODIPY TR, BODIPY 530/550, BODIPY 558/568, BODIPY 564/570, BODIPY 576/589, BODIPY 581/591, BODIPY 630/650, BODIPY 650/665), Carboxyrhodamine 6G, carboxy-X-rhodamine (ROX), Cascade Blue, Cascade Yellow, Coumarin 343, Cyanine dyes (Cy3, Cy5, Cy3.5, Cy5.5), Dansyl, Dapoxyl, Dialkylaminocoumarin, 4',5'-Dichloro-2',7'-dimethoxy-fluorescein, DM-NERF, Eosin,

Erythrosin, Fluorescein, FAM, Hydroxycoumarin, IRDyes (IRD40, IRD 700, IRD 800), JOE, Lissamine rhodamine B, Marina Blue, Methoxy coumarin, Naphtho fluorescein, Oregon Green 488, Oregon Green 500, Oregon Green 514, Pacific Blue, PyMPO, Pyrene, Rhodamine B, Rhodamine 6G, Rhodamine Green, Rhodamine Red, Rhodol Green, 2',4',5',7'-Tetra- bromosulfone-fluorescein, Tetramethyl-rhodamine (TMR), Carboxytetramethylrhodamine (TAMRA), Texas Red, Texas Red-X.

[0054] The term "mass-tag" as used herein refers to any moiety that is capable of being uniquely detected by virtue of its mass using mass spectrometry (MS) detection techniques. Examples of mass-tags include electrophore release tags such as N-[3-[4'-[(p- Methoxytetrafluorobenzyl)oxy]phenyl]-3-methylglyceronyl]ison ipecotic Acid, 4 ' -[2,3 ,5 ,6-

Tetrafluoro-4-(pentafluorophenoxyl)]methyl acetophenone, and their derivatives. The synthesis and utility of these mass-tags is described in United States Patents 4,650,750, 4,709,016, 5,360,8191, 5,516,931, 5,602,273, 5,604,104, 5,610,020, and 5,650,270. Other examples of mass-tags include, but are not limited to, nucleotides, dideoxynucleotides, oligonucleotides of varying length and base composition, oligopeptides, oligosaccharides, and other synthetic polymers of varying length and monomer composition. A large variety of organic molecules, both neutral and charged (biomolecules or synthetic compounds) of an appropriate mass range (100-2000 Daltons) may also be used as mass-tags.

[0055] The term "substrate", as used herein refers to any material or macromolecular complex to which a functionalized end-group of a block copolymer can be attached. Examples of commonly used substrates include, but are not limited to, glass surfaces, silica surfaces, plastic surfaces, metal surfaces, surfaces containing a metalic or chemical coating, membranes (eg., nylon, polysulfone, silica), micro-beads (eg., latex, polystyrene, or other polymer), porous polymer matrices (eg., polyacrylamide gel, polysaccharide, polymethacrylate), macromolecular complexes (eg., protein, polysaccharide).

3. Description of Exemplary Embodiments:

A. Click-Functionalized Targeting Groups

[0056] As described above, the present invention provides targeting groups that are functionalized in a manner suitable for click chemistry. In certain embodiments, the present invention provides a click-functionalized Her-2 binding peptide. Her-2 is a clinically validated receptor target and is over-expressed in 20-30% of breast cancers (Stern D. F., Breast Cancer Res. 2000, 2(3), 176, Fantin V.R., et. al, Cancer Res. 2005, 65(15), 6891). Her-2 over- expression leads to constitutive activation of cell signaling pathways that result in increased cell growth and survival. Her-2 -binding peptides have been developed which retain much of the potency of full-length antibodies such as trastuzamab {i.e. Herceptin) (Fantin V.R. et. al, Cancer Res. 2005, 65(15), 6891, Park B.W., et. al, Nat. Biotechnol 2000, 18(2), 194, Karasseva, N., et. al, J. Protein Chem. 2002, 21(4), 287).

[0057] In certain embodiments, the present invention provides a compound of formula I-a, I-b, or l-c:

I-a I-b

I-c or a salt thereof, wherein each L is independently a valence bond or a bivalent, saturated or unsaturated, straight or branched Cm hydrocarbon chain, wherein 0-6 methylene units of L are independently replaced by -Cy-, -O-, -NH-, -S-, -OC(O)-, -C(O)O-, -C(O)-, -SO-, -SO ₂ -, -NHSO ₂ -, -SO ₂ NH-, -NHC(O)-, -C(O)NH-, -OC(O)NH-, or -NHC(O)O-, wherein:

-Cy- is an optionally substituted 5-8 membered bivalent, saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an optionally substituted 8-10 membered bivalent saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; and each R is independently alkyne or azide. [0058] Exemplary click-functionalized Her-2 binding peptides are set forth below.

[0059] In certain embodiments, a click-functionalized Her-2 binding peptide, in accordance with the present invention, is conjugated to a polymer. In certain embodiments, the polymer is PEG or a functionalized PEG. In other embodiments, a click-functionalized Her-2 binding peptide, in accordance with the present invention, is conjugated to a polymer micelle for tumor-

specific targeting of cancer. In still other embodiments, a click-functionalized Her-2 binding peptide, in accordance with the present invention, is conjugated to micelle having a chemotherapeutic agent encapsulated therein.

[0060] In certain embodiments, the present invention provides a click-functionalized uPAR antagonist. The urokinase-type plasminogen activator receptor (uPAR) is a transmembrane receptor that plays a key role in cell motility and invasion (Mazar A.P., Anticancer Drugs 2001, 12(5), 387). uPAR is an attractive target in cancer therapy as it over-expressed in many types of cancer and expression is usually indicative of a poor patient prognosis (Foekens, J. A., et. al. Cancer Res. 2000, 60(3), 636). Indeed, many antagonists toward uPAR, or uPAR itself, have been developed and have been shown to suppress tumor growth and metastasis both in vitro and in vivo (Reuning, U. et. al., Curr. Pharm. Des. 2003, 9(19), 1529, Romer, J., et. al. Curr. Pharm. Des. 2004, 10(19), 2359).

[0061] In certain embodiments, the present invention provides a compound of formulae II-a, II-b, II-c, H-d, II-e, II-f, II-g, H-h, II-i, II-j, H-k, H-I, H-m, H-n, and II-o, below:

II-a II-b II-c

II-d II-e

II-f II-g

II-h II-i

π-j II-k

II-l

II-m

II-n

ii-o or a salt thereof, wherein each L is independently a valence bond or a bivalent, saturated or unsaturated, straight or branched Cm hydrocarbon chain, wherein 0-6 methylene units of L are independently replaced by -Cy-, -O-, -NH-, -S-, -OC(O)-, -C(O)O-, -C(O)-, -SO-, -SO ₂ -, -NHSO ₂ -, -SO ₂ NH-, -NHC(O)-, -C(O)NH-, -OC(O)NH-, or -NHC(O)O-, wherein:

-Cy- is an optionally substituted 5-8 membered bivalent, saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an optionally substituted 8-10 membered bivalent saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; and each R is independently alkyne or azide.

[0062] One of ordinary skill in the art will recognize that a uPAR antagonist can be click- functionalized at an amine-terminus or at a carboxylate-terminus.

[0063] In certain embodiments, a click-functionalized uPAR antagonist, in accordance with the present invention, is conjugated to a polymer. In certain embodiments, the polymer is PEG or a functionalized PEG. In other embodiments, a click-functionalized uPAR antagonist, in accordance with the present invention, is conjugated to a polymer micelle for tumor-specific targeting of cancer. In still other embodiments, a click-functionalized uPAR antagonist, in accordance with the present invention, is conjugated to micelle having a chemotherapeutic agent encapsulated therein.

[0064] In certain embodiments, the present invention provides a click-functionalized CXCR4 antagonist. CXCR4 is a chemokine receptor that was identified as a co-receptor for HIV entry (De Clercq, E., Nat. Rev. Drug Discov. 2003, 2(7), 581). CXCR4 has also been found to be over- expressed in a majority of breast cancers as described by Muller and colleagues (Muller, A., et. ah, Nature 2001, 410(6824), 50). A number of small molecular antagonists have also been developed towards CXCR4 (De Clercq, E., Nat. Rev. Drug Discov. 2003, 2(7), 581, Gerlach, L.

O., et. al., J. Biol. Chem. 2001, 276(17), 14153, Tamamura, H., et. al, Org. Biomol. Chem. 2003, 1(21), 3656, Tamamura, H., et. al, Mini Rev. Med. Chem. 2006, 6(9), 989, Tamamura, H., et. al, Org. Biomol. Chem. 2006, 4(12), 2354). Other inhibitors of CXCR4, such as short interfering RNA, have also shown remarkable anti-cancer activity in vivo, verifying CXCR4 as a preclinical target for cancer therapy (Lapteva, N., et. al, Cancer Gene Ther. 2005, 12(1), 84, Liang, Z., et. al, Cancer Res. 2004, 64(12), 4302, Liang, Z. et. al, Cancer Res. 2005, 65(3), 967, Smith, M. C, et. al, Cancer Res. 2004, 64(23), 8604).

[0065] In certain embodiments, the present invention provides a click-functionalized folate targeting group. The folate receptor is over-expressed in many epithelial cancers, such as ovarian, colorectal, and breast cancer (Ross, J. F., et. al, Cancer 1994, 73(9), 2432, Jhaveri, M. S., et. al, MoI Cancer Ther. 2004, 3(12), 1505). In addition to being highly overexpressed in cancer cells, little or no expression is found in normal cells (Elnakat, H., et. al, Adv. Drug Deliv. Rev. 2004, 56(8),1067, Weitman, S. D., et. al, Cancer Res. 1992, 52(12), 3396). The non-toxic and non-immunogenic properties of folate make it an excellent ligand for cancer cell targeting. [0066] In certain embodiments, the present invention provides a a click-functionalized compound of formula III:

III or a salt thereof, wherein each L is independently a valence bond or a bivalent, saturated or unsaturated, straight or branched Cm hydrocarbon chain, wherein 0-6 methylene units of L are independently replaced by -Cy-, -O-, -NH-, -S-, -OC(O)-, -C(O)O-, -C(O)-, -SO-, -SO ₂ -, -NHSO ₂ -, -SO ₂ NH-, -NHC(O)-, -C(O)NH-, -OC(O)NH-, or -NHC(O)O-, wherein:

-Cy- is an optionally substituted 5-8 membered bivalent, saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an optionally substituted 8-10 membered bivalent saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; and each R is independently alkyne or azide.

[0067] In certain embodiments, the present invention provides a compound of formula III wherein L is other than -(CH ₂ CH ₂ CH ₂ )- when R is N ₃ .

[0068] In certain embodiments, a click-functionalized folic acid in accordance with the present invention, is conjugated to a polymer. In certain embodiments, the polymer is PEG or a functionalized PEG. In other embodiments, a click-functionalized folic acid, in accordance with the present invention, is conjugated to a polymer micelle for tumor-specific targeting of cancer. In still other embodiments, a click-functionalized folic acid, in accordance with the present invention, is conjugated to micelle having a chemotherapeutic agent encapsulated therein. [0069] In certain embodiments, the present invention provides a click-functionalized GRP78 peptide antagonist. GRP78 (glucose-regulated protein) is a heat shock protein that functions to regulate protein folding and vesicle trafficking (Kim, Y., et. al, Biochemistry 2006, 45(31), 9434). Although expressed in the endoplasmic reticulum in normal cells, it is over-expressed on the surface of many cancer cells (Kim, Y., et. al, Biochemistry 2006, 45(31), 9434, Arap, M. A., et. al, Cancer Cell 2004, 6(3), 275, Liu, Y., et. al., MoI Pharm. 2007). Two groups have independently designed peptides that target GRP78 in vitro and in vivo (Arap, M. A., et. al, Cancer Cell 2004, 6(3), 275, Liu, Y., et. al., MoI Pharm. 2007).

[0070] In certain embodiments, the present invention provides a click-functionalized GRP78 targeting group of formulae IV-a through IV- f:

IV-b

IV-c

IV-d

IV-e

IV-f or a salt thereof, wherein each L is independently a valence bond or a bivalent, saturated or unsaturated, straight or branched Cm hydrocarbon chain, wherein 0-6 methylene units of L are independently replaced by -Cy-, -O-, -NH-, -S-, -OC(O)-, -C(O)O-, -C(O)-, -SO-, -SO ₂ -, -NHSO ₂ -, -SO ₂ NH-, -NHC(O)-, -C(O)NH-, -OC(O)NH-, or -NHC(O)O-, wherein:

-Cy- is an optionally substituted 5-8 membered bivalent, saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an optionally substituted 8-10 membered bivalent saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; and each R is independently alkyne or azide.

[0071] In certain embodiments, a click-functionalized GRP78 peptide antagonist in accordance with the present invention, is conjugated to a polymer. In certain embodiments, the polymer is PEG or a functionalized PEG. In other embodiments, a click-functionalized GRP78

peptide antagonist, in accordance with the present invention, is conjugated to a polymer micelle for tumor-specific targeting of cancer. In still other embodiments, a click-functionalized GRP78 peptide antagonist, in accordance with the present invention, is conjugated to micelle having a chemotherapeutic agent encapsulated therein. [0072] Exemplary click-functionalized GRP78 peptide antagonists are set forth below.

[0073] In some embodiments, the present invention provides a click-functionalized integrin binding peptide. In other embodiments, the present invention provides a click-functionalized RGD peptide. Integrins are transmembrane receptors that function in binding to the extracellular

matrix. Attachment of cells to substrata via intergrins induces cell signaling pathways that are essential for cell-survival; therefore, disruption of integrin-mediated attachment is a logical intervention for cancer therapy (Hehlgans, S., et. al., Biochim. Biophys. Acta 2007, 1775(1), 163). Small linear and cyclic peptides based on the peptide motif RGD have shown excellent integrin binding (Ruoslahti, E., et. al., Science 1987, 238(4826), 491). In one embodiment, linear and cyclic RGD peptides are conjugated to polymer micelles for tumor-specific targeting of cancer.

[0074] In certain embodiments, the present invention provides a compound of formulae V-a, V-b, V-c, V-d, V-e, and V-f:

V-a V-b

V-c V-d

V-e V-f or a salt thereof, wherein each L is independently a valence bond or a bivalent, saturated or unsaturated, straight or branched C^ ₁₂ hydrocarbon chain, wherein 0-6 methylene units of L are independently replaced by -Cy-, -O-, -NH-, -S-, -OC(O)-, -C(O)O-, -C(O)-, -SO-, -SO ₂ -, -NHSO ₂ -, -SO ₂ NH-, -NHC(O)-, -C(O)NH-, -OC(O)NH-, or -NHC(O)O-, wherein:

-Cy- is an optionally substituted 5-8 membered bivalent, saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an optionally substituted 8-10 membered bivalent saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; and each R is independently alkyne or azide.

[0075] In certain embodiments, a click-functionalized RGD peptide in accordance with the present invention, is conjugated to a polymer. In certain embodiments, the polymer is PEG or a functionalized PEG. In other embodiments, a click-functionalized RGD peptide, in accordance with the present invention, is conjugated to a polymer micelle for tumor-specific targeting of cancer. In still other embodiments, a click-functionalized RGD peptide, in accordance with the present invention, is conjugated to micelle having a chemotherapeutic agent encapsulated therein.

[0076] Exemplary compounds of formulae V-a, V-b, V-C, V-d, V-e, and V-f are set forth below.

[0077] In some embodiments, the present invention provides a click-functionalized luteinizing hormone -releasing hormone (LHRH) antagonist peptides. The luteinizing hormone- releasing hormone receptor (LHRHR) was found to be overexpressed in a number of cancer types, including breast, ovarian and prostate cancer cells (Dharap, S. S., et. ah, Proc. Natl. Acad. ScL U. S. A. 2005, 102(36), 12962). LHRH antagonist peptides have been synthesized are are effective in cancer-cell targeting (Dharap, S. S., et. ah, Proc. Natl. Acad. ScL U. S. A. 2005, 102(36), 12962). In one embodiment, peptide antagonists toward LHRHR are conjugated to polymer micelles for tumor-specific targeting of cancer.

[0078] In certain embodiments, the present invention provides a compound of formulae VI- a, VI-b, VI-c, VI-d, and VI-e:

VI-c

VI-d

VI-e or a salt thereof, wherein each L is independently a valence bond or a bivalent, saturated or unsaturated, straight or branched Cm hydrocarbon chain, wherein 0-6 methylene units of L are independently replaced by -Cy-, -O-, -NH-, -S-, -OC(O)-, -C(O)O-, -C(O)-, -SO-, -SO ₂ -, -NHSO ₂ -, -SO ₂ NH-, -NHC(O)-, -C(O)NH-, -OC(O)NH-, or -NHC(O)O-, wherein:

-Cy- is an optionally substituted 5-8 membered bivalent, saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an optionally substituted 8-10 membered bivalent saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; and each R is independently alkyne or azide.

[0079] In certain embodiments, a click-functionalized LHRH antagonist peptide in accordance with the present invention, is conjugated to a polymer. In certain embodiments, the polymer is PEG or a functionalized PEG. In other embodiments, a click-functionalized LHRH antagonist peptide, in accordance with the present invention, is conjugated to a polymer micelle

for tumor-specific targeting of cancer. In still other embodiments, a click-functionalized LHRH antagonist peptide, in accordance with the present invention, is conjugated to micelle having a chemotherapeutic agent encapsulated therein.

[0080] Exemplary compounds of formulae VI-a, VI-b, VI-C, VI-d, and VI-e are set forth below.

[0081] In some embodiments, the present invention provides a click-functionalized aminopeptidase targeting peptide. Aminopeptidase N (CD 13) is a tumor specific receptor that is predominantly expressed in blood vessels surrounding solid tumors. A three amino acid peptide (NGR) was identified to be a cell-binding motif that bound to the receptor aminopeptidase N (Arap, W., et. al., Science 1998, 279(5349), 377, Pasqualini, R., et. al, Cancer Res. 2000, 60(3), 722). The NGR peptide, along with other peptides that target the closely related aminopeptidase A (Marchio, S., et. al., Cancer Cell 2004, 5(2), 151) are targeting group for cancer cells. [0082] In certain embodiments, the present invention provides a compound of formulae VII- a, VII-b, VII-C, and VII-d:

VI-a

VII-b

VII-C

VII-d or a salt thereof, wherein each L is independently a valence bond or a bivalent, saturated or unsaturated, straight or branched Cm hydrocarbon chain, wherein 0-6 methylene units of L are independently replaced by -Cy-, -O-, -NH-, -S-, -OC(O)-, -C(O)O-, -C(O)-, -SO-, -SO ₂ -, -NHSO ₂ -, -SO ₂ NH-, -NHC(O)-, -C(O)NH-, -OC(O)NH-, or -NHC(O)O-, wherein:

-Cy- is an optionally substituted 5-8 membered bivalent, saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an optionally substituted 8-10 membered bivalent saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; and each R is independently alkyne or azide.

[0083] In certain embodiments, a click-functionalized aminopeptidase targeting peptide in accordance with the present invention, is conjugated to a polymer. In certain embodiments, the polymer is PEG or a functionalized PEG. In other embodiments, a click-functionalized aminopeptidase targeting peptide, in accordance with the present invention, is conjugated to a polymer micelle for tumor-specific targeting of cancer. In still other embodiments, a click- functionalized peptides targeting Aminopeptidase N and A, in accordance with the present invention, is conjugated to micelle having a chemotherapeutic agent encapsulated therein. [0084] Exemplary compounds of formulae VII-a, VII-b, VII-c, and VII-d are set forth below.

[0085] In some embodiments, the present invention provides a click-functionalized cell permeating peptide. Cell permeating peptides based on transduction domains such as those derived from the HIV-I Tat protein are promising candidates to improve the intracellular delivery of therapeutic macromolecules and drug delivery systems. HIV-I Tat, and other protein transduction domains, efficiently cross the plasma membranes of cells in an energy dependent fashion, demonstrate effective endosomal escape, and localize in the cell nucleus. (Lindgren, M., et. al., Trends Pharmacol. ScL 2000, 21, 99, Jeang, K. T., et. al., J. Biol. Chem. 1999, 274, 28837, Green, M., et. al., Cell 1988, 55, 1179). The domain responsible for the cellular uptake of HIV-I Tat consists of the highly basic region, amino acid residues 49-57 (RKKRRQRRR) (Pepinsky, R. B., et. al., DNA Cell Biol. 1994, 13, 1011, Vive's, E., et. al., J. Biol. Chem. 1997, 272, 16010, Fawell, S., et. al., Proc. Natl. Acad. ScL U.S.A. 1994, 91, 664). While the detailed mechanism for the cellular uptake of HIV-I Tat remains speculative, the attachment of the HIV TAT PTD and other cationic PTDs {e.g. oligoarginine and penetratin) has been shown to dramatically increase the permeability of drug delivery systems to cells in vitro. (Torchilin, V. P., et. al., Proc. Natl. Acad. ScL U.S.A. 2001, 98, 8786, Snyder, E. L., et. al., Pharm. Res. 2004, 21, 389, Letoha, T., et. al. J. MoI. Recognit. 2003, 16(5), 272). In one embodiment, cell permeating peptides are conjugated to polymer micelles to improve uptake into cancer cells. [0086] In certain embodiments, the present invention provides a compound of formulae VIII-a, VIII-b, VIII-c, VIII-d, VIII-e, and VIII-f:

VIII-a

VIII-b

H

VIII-C

VIII-d

VIII-e

VIII-f or a salt thereof, wherein each L is independently a valence bond or a bivalent, saturated or unsaturated, straight or branched Ci 12 hydrocarbon chain, wherein 0-6 methylene units of L are independently replaced by -Cy-, -0-, -NH-, -S-, -OC(O)-, -C(O)O-, -C(O)-, -SO-, -SO ₂ -, -NHSO ₂ -, -SO ₂ NH-, -NHC(O)-, -C(O)NH-, -OC(O)NH-, or -NHC(O)O-, wherein:

-Cy- is an optionally substituted 5-8 membered bivalent, saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an optionally substituted 8-10 membered bivalent saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; and

each R is independently alkyne or azide.

[0087] In certain embodiments, a click-functionalized cell permeating peptide, in accordance with the present invention, is conjugated to a polymer. In certain embodiments, the polymer is PEG or a functionalized PEG. In other embodiments, a click-functionalized cell permeating peptide, in accordance with the present invention, is conjugated to a polymer micelle for tumor-specific targeting of cancer. In still other embodiments, a click-functionalized cell permeating peptide, in accordance with the present invention, is conjugated to micelle having a chemotherapeutic agent encapsulated therein.

[0088] Exemplary compounds of formulae VIII-a, VIII-b, VIII-c, VIII-d, VIII-e, and VIII- f are set forth below.

[0089] As described herein, the present invention provides targeting groups functionalized for click chemistry. In some embodiments, said functionalization comprises an azide or alkyne moiety. As described above, targeting groups include synthetic peptides having an ability to selectively bind to receptors that are over-expressed on specific cell types. Exemplary targeting groups suitable for derivitization as click-functionalized targeting groups in accordance with the present invention include those set forth in Tables 1-31, below. It will be appreciated that the peptide sequences shown in Tables 1-31, are presented N-terminus to C-terminus, left to right. In a case where a sequence runs over to multiple lines in a row, the each line is a continuation of the sequence on the line above it, left to right. In some embodiments, the peptide sequences listed in Tables 1-31 are cyclized variations of the linear sequences. Table 1. Brain Homing Peptides

Table 2. Kidne Homin Pe tides

Table 3. Heart Homin Pe tides

Table 5. Inte rin Homin Pe tides

Table 12. Synovium Homing Peptides

SEQIDNO: 113 CKSTHDRLC

Table 13. Urothelium Homing Peptides

SEQIDNO: 114 I/LGSGL

Table 14. Prostate Homin Pe tides

Table 15. Lun Homin Pe tides

Table 17. Retina Homin Pe tides

Table 22. Thyroid Homing Peptides

I SEQ ID NO: 549 | SRESPHP I SEQ ID NO: 550 HTFEPGV I

Table 23. Bladder Homing Peptides

I SEQ ID NO: 551 I CSNRDARRC I SEQ ID NO: 552 CXNXDXR(X)/(R)C |

Table 24. Breast Homin Pe tides

Table 25. Neuroblastoma Homing Peptides

I SEQ ID NO: 563 | VPWMEPAYQRFL I SEQ ID NO: 564 | HLQLQPWYPQIS I

Table 26. L m homa Homin Pe tides

Table 27. Muscle Homin Pe tides

Table 28. Wound Vasculature Homing Pe Iptides

SEQ ID NO: 582 CGLIIQKNEC SEQ ID NO: 583 CNAGESSKNC

Table 29. Adipose Tissue Homing Peptides

SEQ ID NO: 584 CKGGRAKDC

Table 30. Virus-binding Peptides

Table 31. Fusogenic Peptides

I SEQ ID NO: 587 I KALA I SEQ ID NO: 588 I RQIKIWFQNRRMKWKK I

[0090] Additional exemplary targeting groups suitable for derivitization as click- functionalized targeting groups in accordance with the present invention include those set forth in Tables 32-38, below. Exemplary peptides that have been shown to be useful for targeting tumors in general in vivo are listed in Table 32. In some cases, the peptide sequences listed in Tables 32-38 are cyclized variations of the linear sequences.

Table 32. Tumor Homin Pe tides

[0091] Additional exemplary targeting groups suitable for derivitization as click- functionalized targeting groups in accordance with the present invention include those set forth in Tables 33-38, below. Exemplary peptides that have been shown to be potentially useful for targeting specific receptors on tumors cells or specific tumor types are listed in Tables 33-38. In some cases, the peptide sequences listed in Tables 33-38 are cyclized variations of the linear sequences.

Table 33. Prostate Specific Membrane Antigen (PSMA) Homing Peptides

Lupoid S and Rodriguez R MoI Cancer Ther 2004;3(5):597-603 Aggarwal S, Cancer Res 2006, 66(18) 9171

Table 34. Aminopeptidase N Homing Peptides

Table 35. HER-2 Homing Peptides

SEQ ID NO: 818 KCCYSL

Karasseva N J Protein Chem 2002;21(4):287-96 Table 36. Colon Cancer Homing Peptides

I SEQ ID NO: 819 I VHLGYAT I SEQ ID NO: 820 I CPIEDRPMC I

Table 37. VEGFRl Homing Peptides

Table 38. CXCR4 Homing Peptides

Kim S., Clin. Exp. Met 2008 25, 201

[0092] One of ordinary skill in the art will recognize that the peptide sequences in Tables 1 - 38 can be click- functionalized at an amine-terminus or at a carboxylate -terminus. [0093] As described above, Tables 1-38 represent lists of synthetic homing peptides, i.e., peptides that home to specific tissues, both normal and cancer. Such peptides are described in, e.g., U.S. Pat. Nos. 6,576,239, 6,306,365, 6,303,573, 6,296,832, 6,232,287, 6,180,084, 6,174,687, 6,068,829, 5,622,699, U.S. Patent Application Publication Nos. 2001/0046498, 2002/0041898, 2003/0008819, 2003/0077826, PCT application PCT/GB02/04017(WO 03/020751), and by Aina, O. et al, MoI Pharm 2007, 4(5), 631.

[0094] Those skilled in the art will recognize methods for identifying and characterizing tissue-homing peptides. For example, see Arap, W., et al., Science 1998, 279(5349), 377, Pasqualini R. and Ruoslahti, E., Nature 1996, 380(6572), 364, Rajotte, D. et al., J. Clin Invest 1998, 102(2), 430, Laakkonen, P., et al., Nat Med. 2002, 8(7), 751, Essler, M. and Ruoslahti E. Proc Natl Acad Sci USA 2002, 99(4), 2252, Joyce J., et al., Cancer Cell 2003, 4(5), 393, Montet X., et al., Bioconjug Chem 2006, 17(4), 905, and Hoffman J. et al., Cancer Cell 2003, 4(5), 383. [0095] In certain embodiments, a click-functionalized targeting group, in accordance with the present invention, is conjugated to a polymer. In certain embodiments, the polymer is PEG or a functionalized PEG. In other embodiments, a click-functionalized targeting group, in accordance with the present invention, is conjugated to a polymer micelle for targeting of tissues

to which the targeting group homes. In still other embodiments, a click- functionalized targeting group, in accordance with the present invention, is conjugated to a micelle having a chemotherapeutic agent encapsulated therein.

[0096] As described above, the present invention provides targeting groups that are functionalized in a manner suitable for click chemistry. In certain embodiments, the targeting group is an oligopeptide. In some embodiments, a click functionalized moiety is introduced to an oligopeptide by reaction of a click- functionalized carboxylic acid with the N-terminus of an oligopeptide. Such click- functionalized carboxylic acids include, but are not limited to:

n = 1 -8 n = 1 -8

[0097] One of ordinary skill in the art will recognize that such carboxylic acids can be introduced to the oligopeptide while on the solid-phase resin or after the peptide has been cleaved from the resin. Such coupling methods include, but are not limited to: aminium/phosphonium-based coupling reagents (e.g. HATU, HBTU, HCTU, TBTU, BOP, PyBOP, PyAOP or HATU/HOBt, HBTU/HOBt, TBTU/HOBt, HCTU/HOBt combinations), carbodiimide -based reagents (e.g. diisopropylcarbodiimide (DIC), dicyclohexylcarbodiimide (DCC), l-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC), or DIC/HOBt, DCC/HOBt, EDC/HOBt combinations), reaction with symmetrical anhydrides of click-functionalized carboxylic acids (prepared through reaction with carbodiimide reagents), reaction with activated esters (e.g. N-hydroxysuccinimide (NHS), pentafluorophenyl (OPfp)) of click-functionalized carboxylic acids, reaction of acid chloride or acid fluoride derivatives of click-functionalized carboxylic acids, and the like.

[0098] In another embodiment, a click functionalized moiety is introduced to an oligopeptide by reaction of a click-functionalized carboxylic acid with primary or secondary amines present on the oligopeptide side-chain. Common amine-functionalized amino acids include natural amino acids such as lysine, arginine, and histidine.

[0099] In one embodiment, a click functionalized moiety is introduced to an oligopeptide by reaction of a click-functionalized amine with the C-terminus of an oligopeptide. Such click- functionalized amines include, but are not limited to:

N,

NH, «T NH, n n = 0-8 n = 0-8

[00100] One of ordinary skill in the art will recognize that such amines can be introduced to the C-terminus of an oligopeptide after the peptide has been cleaved from the resin. Such coupling methods include, but are not limited to: aminium/phosphonium-based coupling reagents (e.g. HATU, HBTU, HCTU, TBTU, BOP, PyBOP, PyAOP or HATU/HOBt, HBTU/HOBt, TBTU/HOBt, HCTU/HOBt combinations), carbodiimide-based reagents (e.g. diisopropylcarbodiimide (DIC), dicyclohexylcarbodiimide (DCC), l-ethyl-3-(3- dimethylaminopropyl)-carbodiimide (EDC), or DIC/HOBt, DCC/HOBt, EDC/HOBt combinations), reaction with activated esters (e.g. N-hydroxysuccinimide (NHS), pentafluorophenyl (OPfp)) of oligopeptides, reaction of acid chloride or acid fluoride derivatives of oligopeptides, and the like.

[00101] In another embodiment, a click functionalized moiety is introduced to an oligopeptide by reaction of a click-functionalized amines with carboxylic acids present on the oligopeptide side-chain. Common carboxylic acid-functionalized amino acids include natural amino acids such as aspartic acid and glutamic acid.

[00102] In yet another embodiment, a click-ready moiety is introduced through incorporation of a click-functionalized amino acid into the oligopeptide backbone. Such click-functionalized amino acids include, but are not limited to:

wherein R' is a natural or unnatural amino acid side-chain group. It will be appreciated that, while L amino acids are depicted above, D amino acids or racemic mixtures may also be used. [00103] In some embodiments, amino acids which are suitably protected for solid-phase chemistry are introduced. Such protected amino acids include, but are not limited to: u O

H U

PG OH PG ^' O OH

OH

wherein R' is a natural or unnatural amino acid side-chain group, and PG is a suitable protecting group. It will be appreciated that, while L amino acids are depicted above, D amino acids or racemic mixtures may also be used. Suitable protecting groups are known in the art and include those described above and by Greene (supra). In some embodiments, PG is an acid (e.g. Boc) or base (e.g. Fmoc) labile protecting group. One of ordinary skill in the art will recognize that such amino acids can be introduced to the N-terminus of an oligopeptide during chain extension on a solid-phase resin. Such coupling methods include, but are not limited to: aminium/phosphonium-based coupling reagents (e.g. HATU, HBTU, HCTU, TBTU, BOP, PyBOP, PyAOP or HATU/HOBt, HBTU/HOBt, TBTU/HOBt, HCTU/HOBt combinations), carbodiimide -based reagents (e.g. diisopropylcarbodiimide (DIC), dicyclohexylcarbodiimide (DCC), l-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC), or DIC/HOBt, DCC/HOBt, EDC/HOBt combinations), preparation of symmetrical anhydrides of click-functionalized amino acids (prepared through reaction with carbodiimide reagents), reaction with activated esters (e.g. N-hydroxysuccinimide (NHS), pentafluorophenyl (OPfp)) of click-functionalized amino acids, reaction of acid chloride or acid fluoride derivatives of click-functionalized amino acids, and the like.

B. Bifunctional PEG 's

[00104] As described herein, provided targeting groups may be conjugated to a suitably functionalized PEG. Such functionalized PEG's are described in detail in U.S. Patent Application Publication Numbers 2006/0240092, 2006/0172914, 2006/0142506, and 2008/0035243, and Published PCT Applications WO07/127473, WO07/127440, and WO06/86325, the entirety of each of which is hereby incorporated herein by reference. [00105] In certain embodiments, the present invention provides a method for conjugating a provided click-functionalized targeting group with a compound of formula A:

A or a salt thereof, wherein: n is 10-2500;

R ¹ and R ² are each independently hydrogen, halogen, NO ₂ , CN, N ₃ , -N=C=O, -C(R)=NN(R) ₂ , -P(O)(OR) ₂ , -P(O)(X) ₂ , a 9-30 membered crown ether, or an optionally substituted group selected from aliphatic, a 3-8 membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, an 8-10 membered saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or a detectable moiety, provided that one of R ¹ and R ² is a moiety suitable for click chemistry; each X is independently halogen; each R is independently hydrogen or an optionally substituted selected from aliphatic or a 3-8 membered, saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; and

L ¹ and L ² are each independently a valence bond or a bivalent, saturated or unsaturated, straight or branched C^ ₁₂ hydrocarbon chain, wherein 0-6 methylene units of L ¹ and L ² are independently replaced by -Cy-, -O-, -NR-, -S-, -OC(O)-, -C(O)O-, -C(O)-, -SO-, -SO ₂ -, -NRSO ₂ -, -SO ₂ NR-, -NRC(O)-, -C(O)NR-, -OC(O)NR-, or -NRC(O)O-, wherein: each -Cy- is independently an optionally substituted 3-8 membered bivalent, saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an optionally substituted 8-10 membered bivalent

saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur, comprising the steps of:

(a) providing a compound of formula A,

(b) providing a click- functionalized targeting compound, and

(c) conjugating the compound of formula A to the targeting compound via click chemistry. [00106] In some embodiments, the preceding steps (a) through (c) provide a compound of formula A-I, A-2, A-3, or A-4:

A-I

A-2

A-3

A-4 wherein the targeting compound is selected from those described herein and each n is 10-2500. In certain embodiments, each n is independently about 225. In other embodiments, n is about 270. In other embodiments, n is about 350. In other embodiments, n is about 10 to about 40. In other embodiments, n is about 40 to about 60. In other embodiments, n is about 60 to about 90. In still other embodiments, n is about 90 to about 150. In other embodiments, n is about 150 to about 200. In still other embodiments, n is about 200 to about 250. In other embodiments, n is about 300 to about 375. In other embodiments, n is about 400 to about 500. In still other

embodiments, n is about 650 to about 750. In certain embodiments, n is selected from 50 ± 10. In other embodiments, n is selected from 80 ± 10, 115 ± 10, 180 ± 10, 225 ± 10, 275 ± 10, 315 ± 10, or 340 ± 10.

[00107] In certain embodiments, the present invention provides a click functionalized targeting group, wherein said click functionalized targeting group is other than:

wherein each R ^a is independently hydrogen or acetyl.

[00108] Table 39 sets forth exemplary compounds of the present invention having the formula: i1 ' ^ ^°}^cr ^E2 wherein n = 10-2500. Table 39.

C. Multiblock Copolymers

[00109] As described herein, provided targeting groups may be conjugated to a polymer micelle. Such polymer micelles are described in detail in U.S. Patent Application Publication Number 2006/0240092, the entirety of which is hereby incorporated herein by reference. [00110] In certain embodiments, the present invention provides a method for conjugating an inventive click-functionalized targeting group with a compound of formula B:

B wherein:

n is 10-2500; m is O to 1000; m' is 1 to 1000;

R ^x is a natural or unnatural amino acid side-chain group that is capable of crosslinking; R ^y is a hydrophobic or ionic, natural or unnatural amino acid side-chain group; R ¹ is -Z(CH ₂ CH ₂ Y)p(CH ₂ ),R ³ , wherein: Z is -O-, -S-, -C≡C-, or -CH ₂ -; each Y is independently -O- or -S-; p is 0-10; t is 0-10; and R ³ is -N ₃ or alkyne;

Q is a valence bond or a bivalent, saturated or unsaturated, straight or branched Ci_i ₂ hydrocarbon chain, wherein 0-6 methylene units of Q are independently replaced by -Cy-, -O-, -NH-, -S-, -OC(O)-, -C(O)O-, -C(O)-, -SO-, -SO ₂ -, -NHSO ₂ -, -SO ₂ NH-, -NHC(O)-, -C(O)NH-, -OC(O)NH-, or -NHC(O)O-, wherein:

-Cy- is an optionally substituted 5-8 membered bivalent, saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an optionally substituted 8-10 membered bivalent saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; R ^2a is a mono-protected amine, a di-protected amine, -N(R ⁴ ) ₂ , -NR ⁴ C(O)R ⁴ , -NR ⁴ C(O)N(R ⁴ ) ₂ , -NR ⁴ C(O)OR ⁴ , or -NR ⁴ SO ₂ R ⁴ , provided that one of R ¹ and R ^2a is a moiety suitable for click chemistry; and each R ⁴ is independently an optionally substituted group selected from hydrogen, aliphatic, a 5-8 membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, an 8-10 membered saturated, partially unsaturated, or aryl bicyclic ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or a detectable moiety, or: two R ⁴ on the same nitrogen atom are taken together with said nitrogen atom to form an optionally substituted 4-7 membered saturated, partially unsaturated,

or aryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, comprising the steps of:

(a) providing a compound of formula B,

(b) providing a click- functionalized targeting compound, and

(c) conjugating the compound of formula B to the targeting compound via click chemistry. [00111] In certain embodiments, a compound of formula B is a triblock copolymer comprising a polymeric hydrophilic block, a poly(amino acid) block, and a mixed random copolymer block. In some embodiments, a compound of formula B further comprises a crosslinked or crosslinkable block, wherein R ^x is a natural or unnatural amino acid side-chain group that is capable of crosslinking (e.g., aspartate, histidine). In some embodiments, a compound of formula B comprises triblock copolymers comprising a polymeric hydrophilic block, a crosslinked or crosslinkable poly(amino acid) block, and an mixed random copolymer block. In some embodiments, m is 0, and a compound of formula B comprises diblock copolymers comprising a hydrophilic block and a mixed random copolymer block. Methods making and using said copolymers and micelles thereof are described in U.S. Patent Application Publication Numbers 2006/0142506, 2006/0172914, and 2006/0240092.

[00112] In certain embodiments, the preceeding steps (a) through (c) provide a compound of formula B-I or B-2:

B-I

B-2 wherein the targeting compound is selected from those described herein.

[00113] Table 40 sets forth exemplary compounds of the present invention having the formula:

Wherein w = 150-400, x=3-30, y=l-50, z=l-50 and p = sum of y and z.

T

[00114] Table 41 sets forth exemplary compounds of the present invention having the formula:

wherein w = 150-400, x=3-30, y=l-50, z=l-50 and p = sum of y and z. Table 41.

[00115] Table 42 sets forth exemplary compounds of the present invention having the formula:

wherein w = 150-400, x=3-30, y=l-50, z=l-50 and p = sum of y and z. T

[00116] Table 43 sets forth exemplary compounds of the present invention having the formula:

wherein w = 150-400, x=3-30, y=l-50, z=l-50 and p = sum of y and z. Table 43.

Compound # A ¹ A ² A ³

[00117] Table 44 sets forth exemplary compounds of the present invention having the formula:

wherein w = 150-400, y=l-50, z=l-50, and p is the sum of y and z.

[00118] Table 45 sets forth exemplary compounds of the present invention having the formula:

wherein w = 150-400, y=l-50, z=l-50, and p is the sum of y and z.

General Methods for Providing Compounds of the Present Invention

[00119] Bifunctional PEG's are prepared according to U.S. Patent Application Publication Numbers 2006/0240092, 2006/0172914, 2006/0142506, and 2008/0035243, and Published PCT Applications WO07/127473, WO07/127440, and WO06/86325, the entirety of each of which is hereby incorporated by reference. Multiblock copolymers of the present invention are prepared by methods known to one of ordinary skill in the art and those described in detail in United States patent application serial number 11/325,020 filed January 4, 2006, the entirety of which is hereby incorporated herein by reference. Generally, such multiblock copolymers are prepared by sequentially polymerizing one or more cyclic amino acid monomers onto a hydrophilic polymer having a terminal amine salt wherein said polymerization is initiated by said amine salt. In certain embodiments, said polymerization occurs by ring-opening polymerization of the cyclic amino acid monomers. In other embodiments, the cyclic amino acid monomer is an amino acid NCA, lactam, or imide. 5. Uses, Methods, and Compositions

Compositions

[00120] According to another embodiment, the invention provides a composition comprising a polymer or polymer micelle conjugated to a targeting group described herein or a pharmaceutically acceptable derivative thereof and a pharmaceutically acceptable carrier, adjuvant, or vehicle. In certain embodiments, such compositions are formulated for administration to a patient in need of such composition. In other embodiments, the composition of this invention is formulated for oral administration to a patient. In some embodiments, compositions of the present invention are formulated for parenteral administration. [00121] In certain embodiments, a micelle conjugated to a provided targeting group is drug loaded. Such drug-loaded micelles of the present invention are useful for treating any disease

wherein the targeting of said micelle to the diseased tissue or cell is beneficial for the delivery of said drug. In certain embodiments, drug-loaded micelles of the present invention are useful for treating cancer. Accordingly, another aspect of the present invention provides a method for treating cancer in a patient comprising adminstering to a patient a multiblock copolymer which comprises a polymeric hydrophilic block, optionally a crosslinkable or crosslinked poly(amino acid block), and a hydrophobic D,L-mixed poly(amino acid block), characterized in that said micelle has a drug-loaded inner core, optionally a crosslinkable or crosslinked outer core, and a hydrophilic shell, wherein said micelle encapsulates a chemotherapeutic agent. [00122] According to another embodiment, the present invention relates to a method of treating a cancer selected from breast, ovary, cervix, prostate, testis, genitourinary tract, esophagus, larynx, glioblastoma, neuroblastoma, stomach, skin, keratoacanthoma, lung, epidermoid carcinoma, large cell carcinoma, small cell carcinoma, lung adenocarcinoma, bone, colon, adenoma, pancreas, adenocarcinoma, thyroid, follicular carcinoma, undifferentiated carcinoma, papillary carcinoma, seminoma, melanoma, sarcoma, bladder carcinoma, liver carcinoma and biliary passages, kidney carcinoma, myeloid disorders, lymphoid disorders, Hodgkin's, hairy cells, buccal cavity and pharynx (oral), lip, tongue, mouth, pharynx, small intestine, colon-rectum, large intestine, rectum, brain and central nervous system, and leukemia, comprising administering a micelle in accordance with the present invention wherein said micelle encapsulates a chemotherapeutic agent suitable for treating said cancer. [00123] P-glycoprotein (Pgp, also called multidrug resistance protein) is found in the plasma membrane of higher eukaryotes where it is responsible for ATP hydrolysis-driven export of hydrophobic molecules. In animals, Pgp plays an important role in excretion of and protection from environmental toxins; when expressed in the plasma membrane of cancer cells, it can lead to failure of chemotherapy by preventing the hydrophobic chemotherapeutic drugs from reaching their targets inside cells. Indeed, Pgp is known to transport hydrophobic chemotherapeutic drugs out of tumor cells. According to one aspect, the present invention provides a method for delivering a hydrophobic chemotherapeutic drug to a cancer cell while preventing, or lessening, Pgp excretion of that chemotherapeutic drug, comprising administering a drug-loaded micelle comprising a multiblock polymer of the present invention loaded with a hydrophobic chemotherapeutic drug. Such hydrophobic chemotherapeutic drugs are well known in the art and include those described herein.

[00124] In certain embodiments, the present invention provides a micelle, as described herein, loaded with an antiproliferative or chemotherapeutic agent selected from any one or more of Abarelix, aldesleukin, Aldesleukin, Alemtuzumab, Alitretinoin, Allopurinol, Altretamine, Amifostine, Anastrozole, Arsenic trioxide, Asparaginase, Azacitidine, BCG Live, Bevacuzimab, Avastin, Fluorouracil, Bexarotene, Bleomycin, Bortezomib, Busulfan, Calusterone, Capecitabine, Camptothecin, Carboplatin, Carmustine, Celecoxib, Cetuximab, Chlorambucil, Cisplatin, Cladribine, Clofarabine, Cyclophosphamide, Cytarabine, Dactinomycin, Darbepoetin alfa, Daunorubicin, Denileukin, Dexrazoxane, Docetaxel, Doxorubicin (neutral), Doxorubicin hydrochloride, Dromostanolone Propionate, Epirubicin, Epoetin alfa, Erlotinib, Estramustine, Etoposide Phosphate, Etoposide, Exemestane, Filgrastim, floxuridine fludarabine, Fulvestrant, Gefitinib, Gemcitabine, Gemtuzumab, Goserelin Acetate, Histrelin Acetate, Hydroxyurea, Ibritumomab, Idarubicin, Ifosfamide, Imatinib Mesylate, Interferon Alfa-2a, Interferon Alfa-2b, Irinotecan, Lenalidomide, Letrozole, Leucovorin, Leuprolide Acetate, Levamisole, Lomustine, Megestrol Acetate, Melphalan, Mercaptopurine, 6-MP, Mesna, Methotrexate, Methoxsalen, Mitomycin C, Mitotane, Mitoxantrone, Nandrolone, Nelarabine, Nofetumomab, Oprelvekin, Oxaliplatin, Paclitaxel, Palifermin, Pamidronate, Pegademase, Pegaspargase, Pegfϊlgrastim, Pemetrexed Disodium, Pentostatin, Pipobroman, Plicamycin, Porfϊmer Sodium, Procarbazine, Quinacrine, Rasburicase, Rituximab, Sargramostim, Sorafenib, Streptozocin, Sunitinib Maleate, Talc, Tamoxifen, Temozolomide, Teniposide, VM-26, Testolactone, Thioguanine, 6-TG, Thiotepa, Topotecan, Toremifene, Tositumomab, Trastuzumab, Tretinoin, ATRA, Uracil Mustard, Valrubicin, Vinblastine, Vincristine, Vinorelbine, Zoledronate, or Zoledronic acid. [00125] Targeting the delivery of potent, cytotoxic agents specifically to cancer cells using responsive nanovectors would have a clear impact on the well-being of the many thousands of people who rely on traditional small molecule therapeutics for the treatment of cancer. In certain embodiments, the present invention provides micelle-encapsulated forms of the common chemotherapy drugs, doxorubicin (adriamycin), a topoisomerase II inhibitor, camptothecin (CPT), a topoisomerase I inhibitor, or paclitaxel (Taxol), an inhibitor of microtubule assembly. [00126] According to one aspect, the present invention provides a micelle, as described herein, loaded with a hydrophobic drug selected from any one or more of a Exemestance (aromasin), Camptosar (irinotecan), Ellence (epirubicin), Femara (Letrozole), Gleevac (imatinib mesylate), Lentaron (formestane), Cytadren/Orimeten (aminoglutethimide), Temodar, Proscar

(finasteride), Viadur (leuprolide), Nexavar (Sorafenib), Kytril (Granisetron), Taxotere (Docetaxel), Taxol (paclitaxel), Kytril (Granisetron), Vesanoid (tretinoin) (retin A), XELODA (Capecitabine), Arimidex (Anastrozole), Casodex/Cosudex (Bicalutamide), Faslodex (Fulvestrant), Iressa (Gefitinib), Nolvadex, Istubal, Valodex (tamoxifen citrate), Tomudex (Raltitrexed), Zoladex (goserelin acetate), Leustatin (Cladribine), Velcade (bortezomib), Mylotarg (gemtuzumab ozogamicin), Alimta (pemetrexed), Gemzar (gemcitabine hydrochloride), Rituxan (rituximab), Revlimid (lenalidomide), Thalomid (thalidomide), Alkeran (melphalan), and derivatives thereof.

[00127] The term "patient", as used herein, means an animal, preferably a mammal, and most preferably a human.

[00128] The term "pharmaceutically acceptable carrier, adjuvant, or vehicle" refers to a nontoxic carrier, adjuvant, or vehicle that does not destroy the pharmacological activity of the compound with which it is formulated. Pharmaceutically acceptable carriers, adjuvants or vehicles that may be used in the compositions of this invention include, but are not limited to, ion exchangers, alumina, aluminum stearate, lecithin, serum proteins, such as human serum albumin, buffer substances such as phosphates, glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, salts or electrolytes, such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, cellulose-based substances, polyethylene glycol, sodium carboxymethylcellulose, polyacrylates, waxes, polyethylene-polyoxypropylene-block polymers, polyethylene glycol and wool fat. [00129] Pharmaceutically acceptable salts of the compounds of this invention include those derived from pharmaceutically acceptable inorganic and organic acids and bases. Examples of suitable acid salts include acetate, adipate, alginate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, citrate, camphorate, camphorsulfonate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate, glucoheptanoate, glycerophosphate, glycolate, hemisulfate, heptanoate, hexanoate, hydrochloride, hydrobromide, hydroiodide, 2- hydroxy ethanesulfonate, lactate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oxalate, palmoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate, pivalate, propionate, salicylate, succinate, sulfate, tartrate, thiocyanate, tosylate and undecanoate. Other acids, such as oxalic, while not in themselves pharmaceutically acceptable,

may be employed in the preparation of salts useful as intermediates in obtaining the compounds of the invention and their pharmaceutically acceptable acid addition salts.

[00130] Salts derived from appropriate bases include alkali metal (e.g., sodium and potassium), alkaline earth metal (e.g., magnesium), ammonium and N+(Cl-4 alkyl)4 salts. This invention also envisions the quaternization of any basic nitrogen-containing groups of the compounds disclosed herein. Water or oil-soluble or dispersible products may be obtained by such quaternization.

[00131] The compositions of the present invention may be administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or via an implanted reservoir. The term "parenteral" as used herein includes subcutaneous, intravenous, intramuscular, intraarticular, intra-synovial, intrasternal, intrathecal, intrahepatic, intralesional and intracranial injection or infusion techniques. Preferably, the compositions are administered orally, intraperitoneally or intravenously. Sterile injectable forms of the compositions of this invention may be aqueous or oleaginous suspension. These suspensions may be formulated according to techniques known in the art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution or suspension in a nontoxic parenterally acceptable diluent or solvent, for example as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium.

[00132] For this purpose, any bland fixed oil may be employed including synthetic mono- or di-glycerides. Fatty acids, such as oleic acid and its glyceride derivatives are useful in the preparation of injectables, as are natural pharmaceutically-acceptable oils, such as olive oil or castor oil, especially in their polyoxyethylated versions. These oil solutions or suspensions may also contain a long-chain alcohol diluent or dispersant, such as carboxymethyl cellulose or similar dispersing agents that are commonly used in the formulation of pharmaceutically acceptable dosage forms including emulsions and suspensions. Other commonly used surfactants, such as Tweens, Spans and other emulsifying agents or bioavailability enhancers which are commonly used in the manufacture of pharmaceutically acceptable solid, liquid, or other dosage forms may also be used for the purposes of formulation.

[00133] The pharmaceutically acceptable compositions of this invention may be orally administered in any orally acceptable dosage form including, but not limited to, capsules, tablets, aqueous suspensions or solutions. In the case of tablets for oral use, carriers commonly used include lactose and corn starch. Lubricating agents, such as magnesium stearate, are also typically added. For oral administration in a capsule form, useful diluents include lactose and dried cornstarch. When aqueous suspensions are required for oral use, the active ingredient is combined with emulsifying and suspending agents. If desired, certain sweetening, flavoring or coloring agents may also be added. In certain embodiments, pharmaceutically acceptable compositions of the present invention are enterically coated.

[00134] Alternatively, the pharmaceutically acceptable compositions of this invention may be administered in the form of suppositories for rectal administration. These can be prepared by mixing the agent with a suitable non-irritating excipient that is solid at room temperature but liquid at rectal temperature and therefore will melt in the rectum to release the drug. Such materials include cocoa butter, beeswax and polyethylene glycols.

[00135] The pharmaceutically acceptable compositions of this invention may also be administered topically, especially when the target of treatment includes areas or organs readily accessible by topical application, including diseases of the eye, the skin, or the lower intestinal tract. Suitable topical formulations are readily prepared for each of these areas or organs. [00136] Topical application for the lower intestinal tract can be effected in a rectal suppository formulation (see above) or in a suitable enema formulation. Topically-transdermal patches may also be used.

[00137] For topical applications, the pharmaceutically acceptable compositions may be formulated in a suitable ointment containing the active component suspended or dissolved in one or more carriers. Carriers for topical administration of the compounds of this invention include, but are not limited to, mineral oil, liquid petrolatum, white petrolatum, propylene glycol, polyoxyethylene, polyoxypropylene compound, emulsifying wax and water. Alternatively, the pharmaceutically acceptable compositions can be formulated in a suitable lotion or cream containing the active components suspended or dissolved in one or more pharmaceutically acceptable carriers. Suitable carriers include, but are not limited to, mineral oil, sorbitan monostearate, polysorbate 60, cetyl esters wax, cetearyl alcohol, 2-octyldodecanol, benzyl alcohol and water.

[00138] For ophthalmic use, the pharmaceutically acceptable compositions may be formulated as micronized suspensions in isotonic, pH adjusted sterile saline, or, preferably, as solutions in isotonic, pH adjusted sterile saline, either with or without a preservative such as benzylalkonium chloride. Alternatively, for ophthalmic uses, the pharmaceutically acceptable compositions may be formulated in an ointment such as petrolatum.

[00139] The pharmaceutically acceptable compositions of this invention may also be administered by nasal aerosol or inhalation. Such compositions are prepared according to techniques well-known in the art of pharmaceutical formulation and may be prepared as solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbons, and/or other conventional solubilizing or dispersing agents.

[00140] In certain embodiments, the pharmaceutically acceptable compositions of this invention are formulated for oral administration.

[00141] The amount of the compounds of the present invention that may be combined with the carrier materials to produce a composition in a single dosage form will vary depending upon the host treated, the particular mode of administration. Preferably, the compositions should be formulated so that a dosage of between 0.01 - 100 mg/kg body weight/day of the drug can be administered to a patient receiving these compositions.

[00142] It will be appreciated that dosages typically employed for the encapsulated drug are contemplated by the present invention. In certain embodiments, a patient is administered a drug- loaded micelle of the present invention wherein the dosage of the drug is equivalent to what is typically administered for that drug. In other embodiments, a patient is administered a drug- loaded micelle of the present invention wherein the dosage of the drug is lower than is typically administered for that drug.

[00143] It should also be understood that a specific dosage and treatment regimen for any particular patient will depend upon a variety of factors, including the activity of the specific compound employed, the age, body weight, general health, sex, diet, time of administration, rate of excretion, drug combination, and the judgment of the treating physician and the severity of the particular disease being treated. The amount of a compound of the present invention in the composition will also depend upon the particular compound in the composition.

[00144] In order that the invention described herein may be more fully understood, the following examples are set forth. It will be understood that these examples are for illustrative purposes only and are not to be construed as limiting this invention in any manner.

EXEMPLIFICATION

General synthesis of click- functionalized saccharides

Scheme for Selective functionalization of Folate

©

Example

Example 1

Fmoc-(But)S— ξ _j H ₂ N-G-R(Pbf)-G-D(But)-S(But)-

Ser-loaded Wang resin O

HBTU/HOBt

OH

ξ

[00145] Synthesis of Acetylene-terminated GRGDS peptide - The oligopeptide sequence GRGDS was synthesized according to standard Fmoc solid phase peptide synthesis using a batch wise process and the peptide coupling agent HBTU. Fmoc-Ser(But)-loaded Wang resin (3.2 g with loading density of 0.6 mmol/g) was weighed into an oven-dried glass-fritted reaction tube

and swollen with 30 mL dry CH ₂ Cl ₂ for 5-10 minutes. The Fmoc group at the JV-terminus was cleaved by the addition of a 25/75 solution of piperidine/DMF (30 mL), followed by agitation with nitrogen for three minutes. The resin was filtered, and fresh piperidine/DMF (30 mL) was added. After agitating for 20 minutes, the resin was filtered and washed with DMF six times. [00146] A solution of Fmoc-Asp(OBut)-OH (3.85 g, 9.35 mmol), HBTU (3.48 g, 9.17 mmol), and HOBt (1.26 g, 9.35 mmol) in 20 mL of anhydrous DMF was prepared. After the solution became homogeneous, DIPEA (3.28 mL, 18.70 mmol) was added, and the resulting mixture was added immediately to the resin. The resin was then agitated for one hour, filtered, and washed with DMF (three times). A 25/75 solution of piperidine/DMF (30 mL) was added, and the resin agitated for three minutes. After filtration, piperidine/DMF was again added to the resin followed by agitation for 20 minutes. The resin was then washed with DMF (six times). The above amino acid addition procedure was repeated for Fmoc-Gly-OH, Fmoc-Arg(Pbf)-OH, and a second unit of Fmoc-Gly-OH.

[00147] Following the addition of the second GIy unit, a solution of 4-pentynoic acid (0.90 g, 9.0 mmol), HBTU (3.4 g, 8.8 mmol), and HOBt (1.4 g, 9.0 mmol) was prepared in 15 mL of dry DMF. After the solution became homogeneous, DIPEA (3.2 mL, 18.0 mmol) was added, and the resulting mixture was added immediately to the resin. The resin was then agitated for one hour, filtered, and washed with DMF (six times). After filtration, the resin was washed with DMF (six times) followed by CH ₂ Cl ₂ (four times) to remove any residual DMF. The oligopeptide was then cleaved by agitating the resin with 95/2.5/2.5 TFA/H ₂ O/TIPS (30 ml) for three hours. The filtrated was collected in a clean flask, and the resin was washed with fresh cleavage solution and DCM several times. The solution was concentrated on a rotary evaporator and dissolved in minimal MeOH. The oligopeptide was precipitated from diethyl ether and isolated by filtration.

Example 2

Arg(Pbf)-loaded Wang resin O

HATU

OH

[00148] Synthesis of Acetylene-terminated RRRRRRRR peptide - The oligopeptide sequence RRRRRRRR was synthesized according to standard Fmoc solid phase peptide synthesis using a batch wise process and the peptide coupling agent HBTU. Fmoc-Arg(Pbf)- loaded Wang resin (3.0 g with loading density of 0.6 mmol/g) was weighed into an oven-dried glass-fritted reaction tube and swollen with 30 rnL dry CH ₂ Cl ₂ for 5-10 minutes. The Fmoc group at the JV-terminus was cleaved by the addition of a 25/75 solution of piperidine/DMF (30 mL), followed by agitation with nitrogen for three minutes. The resin was filtered, and fresh piperidine/DMF (30 mL) was added. After agitating for 20 minutes, the resin was filtered and washed with DMF six times.

[00149] A solution of Fmoc-Arg(Pbf)-OH (5.8 g, 9.0 mmol) and HATU (3.3 g, 8.7 mmol), in 20 mL of anhydrous DMF was prepared. After the solution became homogeneous, DIPEA (3.2 mL, 18.0 mmol) was added, and the resulting mixture was added immediately to the resin. The resin was then agitated for thirty minutes, filtered, and washed with DMF (three times). A 25/75 solution of piperidine/DMF (30 mL) was added, and the resin agitated for three minutes. After filtration, piperidine/DMF was again added to the resin followed by agitation for 20 minutes. The resin was then washed with DMF (six times). The above amino acid addition procedure was repeated for the remaining six couplings of Fmoc-Arg(Pbf)-OH.

[00150] Following the addition of the eighth Arg unit, a solution of 4-pentynoic acid (0.90 g, 9.0 mmol) and HATU (3.3 g, 8.7 mmol) was prepared in 15 mL of dry DMF. After the solution became homogeneous, DIPEA (3.2 mL, 18.0 mmol) was added, and the resulting mixture was added immediately to the resin. The resin was then agitated for thirty minutes, filtered, and

washed with DMF (six times). After filtration, the resin was washed with DMF (six times) followed by CH ₂ Cl ₂ (four times) to remove any residual DMF. The oligopeptide was then cleaved by agitating the resin with 95/2.5/2.5 TFA/H ₂ O/TIPS (30 ml) for three hours. The filtrated was collected in a clean flask, and the resin was washed with fresh cleavage solution and DCM several times. The solution was concentrated on a rotary evaporator and dissolved in minimal MeOH. The oligopeptide was precipitated from diethyl ether and isolated by filtration to give 1.6 g of an off-white powder.

[00151] Conjugation of GRGDS to N ₃ -PEG8K-6-Poly(Aspi ₀ ) -0-PoIy(GIu(BzI) ₂ O) via "Click" chemistry - N ₃ -PEG8K-6-Poly(Aspi ₀ ) -6-Poly(Glu(Bzl) ₂₀ ) (96.0mg), alkyne-GRGDS (2.4 mg), CuSO ₄ (70 μL of a 10 mM stock solution in degassed, deionized water), sodium ascorbate (93 μL of a 150 mM stock solution in degassed, deionized water), and bathophenanthrolinedisulfonic acid (70 μL of a 30 mM stock solution in degassed, deionized water) and 0.5 mL of degassed, deionized water were combined (in that order) and stirred for 24 hours at room temperature under argon. Ethylenediaminetetraacetic acid disodium salt dihydrate (EDTA, 50 mg) was added to the reaction and allowed to stir for one hour. The product of the reaction was dialyzed twice against deionized water (1OK MWCO membrane) and freeze-dried.

GRGDS-functionalized PEG8K-6-Poly(Aspio) -ό-Poly(Glu(Bzl) ₂₀ ) was recovered as a fluffy white powder.

Example 4

θlιgoargιnιne-/3-PEG12K-b-Poly(DGIu(Bzl) ₁₅ -co-LGIu(Bzl) ₁₅ )-Ac

[00152] Conjugation of oligoarginine to N ₃ -PEGIIk-^-POIy(DGIU(BzI) _I5 -Co-LGIu(BzI) _I5 ) via "Click" chemistry - N ₃ -PEGIIk-O-POIy(DGIU(BzI) _I5 -Co-LGIu(BzI) _I5 ) (33.0mg, l.δμmol), alkyne-oligoarginine (0.5mL of a 8.3mg/mL stock solution in deionized water, 1.8μmol), CuSO ₄ (0.5mL of a 94.6mg/L stock solution in deionized water, 0.19μmol), sodium ascorbate (16.2mg, 82μmol), and an ionic benzimidazole ligand (BimC4A)3 (0.25mL of a lmg/mL aqueous stock solution in deionized water, 0.35μmol) and 0.5mL of deionized water were combined (in that order) and stirred for 24 hours at room temperature. Ethylenediaminetetraacetic acid disodium salt dihydrate (EDTA, 6.8mg, 18.3μmol) was added to the reaction and allowed to stir for one

hour. The product of the reaction was dialyzed twice against deionized water (1OK MWCO membrane) and freeze-dried. Oligoarginine-functionalzed PEG12k-b-Poly(DGlu(Bzl)i ₅ -co- LGlu(Bzl)i ₅ ) was recovered as a fluffy white powder (23mg, Yield= 62%). For more details on (BimC4A) ₃ , see Rodionov, et. al., J. Am. Chem. Soc. 2007, 129, 12696.

Coumarin-jb-PEG12K-b-Poly(DGIu(Bzl) ₁₅ -co-LGIu(Bzl) ₁₅ )-Ac

[00153] Conjugation of 4-methyl coumarin to N ₃ -PEGIIk-^-PoIy(DGIu(BzI)I ₅ -CO- LGIu(BzI) ₁₅ ) via "Click" chemistry - N ₃ -PEG12k-b-Poly(DGlu(Bzl)i ₅ -co-LGlu(Bzl)i ₅ ) (33.0mg, 1.8μmol), acetylene-functionalized, 4-methyl coumarin (0.5mL of a 0.7mg/mL stock

solution in ¹ BuOH, 1.9μmol)) CuSO ₄ (0.5mL of a 94.6mg/L stock solution in deionized water, 0.19μmol), sodium ascorbate (16.2mg, 82μmol), (BimC4A) ₃ (0.25mL of a 1 mg/mL aqueous stock solution in deionized water, 0.35μmol) and 0.5mL of deionized water were combined (in that order) and allowed to stir for 24 hours at room temperature. Ethylenediaminetetraacetic acid disodium salt dihydrate (EDTA, 6.8mg, 18.3μmol) was added to the reaction and allowed to stir for one hour. The product of the reaction was dialyzed twice against deionized water (1OK MWCO membrane) and freeze-dried. Coumarin-functionalized PEG12k-b-Poly(DGlu(Bzl)is-co- LGlu(Bzl)i ₅ ) was recovered as a fluffy white powder (23mg, Yield= 62%). [00154] While we have described a number of embodiments of this invention, it is apparent that our basic examples may be altered to provide other embodiments that utilize the compounds and methods of this invention. Therefore, it will be appreciated that the scope of this invention is to be defined by the appended claims rather than by the specific embodiments that have been represented by way of example.