INDICATOR COMPOUNDS, POLYMERIZABLE DERIVATIVES THEREOF AND INFECTION INDICATING MEDICAL DEVICES COMPRISING THE SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit under 35 U.S. C. § 119(e) to U.S. provisional application serial no. 61/858,077, filed July 24, 2013, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] This invention relates to compounds of Formula (I), (II), (III) and (IV) which preferably act as pH indicators. This invention also relates to such indicator compounds of Formula (I), (II), (III) and (IV) that contain one or more polymerizable functional groups to participate with polymerizable monomers in polymer formation and/or to covalently link the indicator compounds to a wound covering, probes, a polymer or an implantable medical device, or a portion of any thereof. This invention further relates to such implantable medical devices, probes, wound coverings and polymers, having covalently bound indicator compounds, where the implanted device is capable of self-reporting microbial growth adjacent to or on the implanted device and non-invasive methods to self-report the microbes at the infection site.

BACKGROUND OF THE INVENTION

[0003] Infections on the skin surface or internally such at the site of implantation of a medical device are a serious problem. For example, surgeries relating to breast implants result in infection rates from about 2 % to as high as 20 % in women undergoing such implants, with the highest rate of infection in reconstructive cases. Feldman, et al., Plast. Reconstr. Surg., 126(3): 779-85 (2010). Similarly, prosthetic joint infections are a frequent cause of prosthesis failure. Gemmel, et al, Eur. J. Nucl. Med. Mol. Imaging, 39(5):892-909 (2012). A variety of bacteria and fungi may be involved in such infections, with

staphylococci, including Staphylococcus epidermidis and S. aureus, accounting for a majority of infections.

[0004] Frequently, infection at the site of implantation of a medical device requires that the device be removed and/or replaced. This results in increased risk to the patient as well as increased cost. In addition, infection at a wound site or internally (whether at the site of a medical implant) can lead to serious illness, and even death, if the infection is unnoticed and untreated for even a relatively short period of time. Undetected bacterial infection may result in sepsis, septic phlebitis, septic shock, bacteraemia, tunnel infection, and/or metastatic complications (e.g., endocarditis, osteomyelitis, or septic thrombosis). Accordingly, early detection of bacterial infection is highly desirable.

[0005] Therefore, a need exists for methods and medical devices for the early detection of bacterial growth at a surface wound site or internally such at or around the implantation site of a medical device that can readily detect and indicate the presence of active microbial growth well before the infection has progressed to the point that it manifests itself by clinical symptoms.

SUMMARY OF THE INVENTION

[0006] This invention provides for novel compounds that are indicators for use in determining the presence of an active microbial growth in a patient. In one aspect, provided herein are compounds of Formulas (I), (II), (III) and (IV):

or a pharmaceutically acceptable salt thereof, wherein

each of p, q, and r independently is 0, 1 or 2;

R ¹ , R ² and R ³ independently are hydrogen, Pg, L-R ⁴ , Ci-C ₆ alkyl, C3-C8 cycloalkyl, or phenyl, each of which are optionally substituted with 1-5, preferably, 1-3 substituents selected from the group consisting of halo, preferably fluoro, cyano, Ci-C ₆ alkoxy, and aryloxy;

R ⁴ is a polymerizable group or a reactive group;

6 7 8 9 28 29

R , R , R , R , R and R independently are hydrogen or Ci-C ₆ alkyl, optionally substituted with or L-R ⁴ ;

each X independently is:

-OR ³ ;

L-R ⁴ ;

Ci-C ₆ alkyl, C ₁ -C ₁₀ heteroalkyl, C ₃ -C ₈ cycloalkyl or C ₃ -C ₈ heterocyclyl,

optionally substituted with 1-3 phenyl, oxo, cyano, halo, nitro;

C ₆ -Cio aryl or C ₂ -C ₁₀ heteroaryl having 1-6 ring heteroatoms selected

preferably from N, O, S, and P and oxidized forms of N, S, and P, wherein the aryl or heteroaryl is optionally substituted with 1-4, preferably 1-3, more preferably 1-2, and still more preferably 1 substituent, wherein the substituent is selected from the group consisting of alkyl, preferably Ci-C ₆ alkyl, -OR ¹⁸ , wherein R ¹⁸ is alkyl, preferably Ci-C ₆ alkyl, C ₃ -C ₈ cycloalkyl, C6-C10 aryl, preferably phenyl, each of which are optionally substituted with 1-5, preferably, 1-3 substituents selected from the group consisting of halo, preferably fluoro, cyano, Ci-C ₆ alkoxy, and aryloxy; cyano, halo, nitro; -C0 ₂ H, -C0 ₂ _Ci-C ₆ alkyl, -CO ₂ _C ₆ -Ci ₀ aryl, SR ³ ; -

CONR ²⁸ R ²⁹ or -S0 ₂ NR ²⁸ R ²⁹ ;

or two adjacent X substituents may combine with the carbon atoms to which they are joined to form an C ₆ -Cio aryl heterocyclic, C ₃ -C ₈ cycloalkyl, or C ₃ -C ₈ heterocyclyl ring;

Z is C or S;

v is 1 if Z is C, and v is 1 or 2 if Z is S;

A is an anionic counterion;

Pg is a hydroxyl protecting group;

L is a covalent bond or a linker which joins the one or more polymerizable groups or reactive groups to the oxygen atom to which it is attached;

provided that:

the compound of Formula (I) is not o-cresolphthalein, phenolphthalein,

thymolphthalein, guaiacolphthalein, a-naphtholphthalein, tetrabromophenolphthalein or xylenolphthalein;

the compound of Formula (II) is not phenol red, o-cresol red, thymol blue, m-cresol purple, chlorophenol red, bromophenol red, bromophenol blue, bromoxylenol blue, bromocresol purple or xylenol blue;

the compound of Formula (III) is not alizarin red; and

the compound of Formula (IV) is not a-dinitrophenol, β-dinitrophenol, γ- dinitrophenol, ε-dinitrophenol, δ-dinitrophenol, o-nitrophenol, m-nitrophenol, p-nitrophenol or picric acid.

[0007] In some embodiments, at least one of R and R ² is L-R ⁴ , and/or p + q + r is at least 1 and X is -OL-R ⁴ .

[0008] Also provided herein are polymers which contain an indicator compound of Formulas (I), (II), (III) and (IV), or reaction products therefrom, covalently bound to the polymer, wherein sufficient indicator is bound to the polymer such that the color of the polymer is changed from transparent at neutral pH to colored at acidic pH. In one aspect, a polymer or co-polymer is provided, comprising an indicator compound of Formulas (I), (II), (III) and (IV), or reaction products therefrom, covalently bound to the polymer or copolymer. In some embodiments, the polymer or co-polymer comprises a biodegradable material such as those described herein. [0009] Further provided herein are wound coverings containing the indicator-polymer compounds described herein as well as implantable medical devices comprising on at least part of their surface, covalently bound self-identifying indicator compounds of Formulas (I), (II), (III) and (IV), or reaction products therefrom, which indicator compounds produce or can be induced to produce a differential signal under acidic pH as compared to the signal produced at neutral or alkaline pH wherein said signal can be assessed ex vivo.

[0010] The implantable medical devices, as disclosed herein, may include polymers or copolymers having the indicator compound of Formula (I), (II), (III) or (IV) throughout the polymers or copolymers. For example, the indicator compound of Formula (I), (II), (III) or (IV) may comprise acrylate reactive groups that are polymerized into copolymers that are used to make the implantable medical device or components thereof. As such, in this embodiment, the compound of Formula (I), (II), (III) or (IV) is incorporated both at and beneath the surface of said component of the device.

[0011] Preferably, the implantable medical devices, as disclosed herein, may have the indicator compound of Formula (I), (II), (III) or (IV) incorporated, via a polymerizable group, at the surface of the implantable medical device, or a component of the device, without substantially being incorporated beneath the surface. For example, the indicator compound of Formula (I), (II), (III) or (IV) having one or more reactive groups such as an isocyanate or thioisocyanate may be formulated into a composition and sprayed onto the surface of the implantable medical device after the device has been manufactured. The one or more reactive groups of the compound of Formula (I), (II), (III) or (IV) can react with a group such as an amino, hydroxyl and/or thiol group on the surface of a copolymer structure of the implantable medical device to form covalent bonds. In some embodiments, the copolymer includes polyvinyl alcohol, PVA, or copolymers derived from 2-hydroxyethyl methacrylate, HEMA. As such, in this embodiment, the compound of Formula (I), (II), (III) or (IV) is incorporated substantially at the surface of the implantable medical device or a PVA, HEMA or PEG-derived component of the device.

[0012] In one embodiment, some of the self-identifying indicator compounds of Formulas (I), (II), (III) and (IV), or reaction products therefrom, are pH sensitive dyes which change structure and hence alter at least one of their electromagnetic emission characteristics in going from an alkaline or neutral pH to an acidic pH. In yet another embodiment, these indicator compounds are pH sensitive fluorescent indicators.

[0013] In another embodiment, the medical device described herein further contains on at least part of its surface an antibody or binding fragment thereof which specifically binds to a microbe and produces a signal indicating the identity of the microbe bound thereto. In some embodiments, the antibody or binding fragment thereof has bound thereto a reporter, such as a fluorescent moiety which changes its fluorescent character upon binding to the microbe. In some embodiments, a plurality of different antibodies or binding fragments thereof are bound to the medical device, each producing a unique signal for the microbe bound thereto.

[0014] In one embodiment, the medical devices further contain self-identifying reporters in combination with the indicators set forth above. Such reporters include compounds bound to the antibody or binding fragment thereof and which emit a differential signal when bound to the microbe as compared to that when not bound to the microbe. For example, such a differential signal can be a signal arising from a change in at least one electromagnetic emission character of the reporter when bound as opposed to when not bound to the microbe. In some embodiments, the compound bound to the antibody or binding fragment thereof is an indicator compound of Formulas (I), (II), (III) and (IV), or reaction products therefrom. In some embodiments, the compounds bound to the antibody or binding fragment thereof is not an indicator compound of Formulas (I), (II), (III) and (IV), or reaction products therefrom.

[0015] In yet another embodiment, these reporters are fluorescent indicators which have an altered fluorescence when bound to the microbe as compared to being unbound.

[0016] In one of its method aspects, this invention provides for an ex vivo method to determine the presence of an infection at or adjacent to a medical device implanted in a patient which method comprises

selecting an implantable medical device having on at least part of its surface self- identifying indicators which indicators produce a differential signal under acidic pH as compared to the signal produced at neutral or alkaline pH wherein said signal can be assessed ex vivo,

placing said medical device in a patient;

monitoring ex vivo the signal produced by the self-identifying indicator; and correlating the signal so produced to the presence or absence of an active infection; where the self-identifying indicator comprises a reaction product of Formula (I), (II), (III) or (IV).

[0017] Also provided herein are ex vivo methods to determine the microbe present in an infection at or adjacent to a medical device implanted in a patient which method comprises selecting an implantable medical device having on at least part of its surface self- identifying reporters which reporters produce a differential signal when bound to a microbe as compared to the signal produced when not bound to a microbe wherein said signal can be assessed ex vivo,

placing said medical device in a patient;

monitoring ex vivo the signal produced by the self-identifying reports; and

correlating the signal so produced to the presence or absence of the microbe at an active infection;

where the self-identifying indicator comprises a reaction product of Formula (I), (II), (III) or (IV).

[0018] In one embodiment, the signal produced by the indicator and/or reporter on the implanted medical device is measured immediately after implantation and that signal is used as a baseline or reference signal for comparison to future signals so as to aid the clinician in determining the degree of change in the emitted signal or signals.

[0019] In some embodiments, the method further comprises treating a patient with antimicrobial compounds, such as antibiotics.

[0020] In another aspect, a method is provided for assessing active bacterial growth at a site capable of sponsoring bacterial growth which method comprises:

placing on or adjacent said site an indicator capable of a first electronic configuration in the absence of active bacterial growth and a second electronic configuration in the presence of active bacterial growth said second electronic configuration exhibiting a unique electromagnetic spectrum as compared to the first structure;

employing instrumentation which compares at least a portion of said spectrum to assess the presence of said second electronic configuration on or adjacent said site and which provides a readable result of said comparison; and

determining from said readable result whether said comparison evidences active bacterial growth. [0021] In some embodiments, the first electronic configuration and the second electronic configuration correspond to different chemical structures in equilibrium, such as those associated with the compounds of Formula (I) and (la) provided herein. In some

embodiments, the first electronic configuration and the second electronic configuration correspond to different tautomers in equilibrium. In some embodiments, the equilibrium is pH dependent. For example, as the compounds of Formula (I)-(IV) are exposed to changes in pH, the compounds can undergo structural and/or tautomeric changes that can be detected, qualitatively and/or quantitatively because the different structures and/or tautomers emit distinctive bands of radiation that can be detected and/or quantified.

[0022] In some embodiments, the instrumentation can recognize and/or quantify electromagnetic radiation, or a portion thereof, and correlate the radiation with the relative amount of the first electronic configuration and/or the second electronic configuration.

[0023] In some embodiments, the instrumentation is in vivo with respect to a subject and the instrumentation emits an "indirect" readable result, meaning that the readable result is generally ascertained by a user with the aid of additional instrumentation. The additional instrumentation, for example, can be an apparatus that detects or senses electromagnetic radiation being emitted by the second electronic configuration of the indicator within the body of a subject and provides a signal to a user. The signal may be e.g. a light or sound, indicating the presence and/or the quantity of the second electronic configuration. In some embodiments, the additional instrumentation includes a means for radio -frequency identification (RFID) of the second electronic configuration.

[0024] In some embodiments, the instrumentation is ex vivo with respect to a subject and the instrumentation emits a "direct" readable result, meaning that the readable result can generally be ascertained by a user without additional instrumentation. For example, a readable result such as color change on the surface of a bandage that covers a wound can generally be ascertained by a user upon inspection of the bandage. The bandage may be configured to turn a color or emit a particular wavelength of light to convey the presence of the second electronic configuration of the indicator.

[0025] In some embodiments, the first electronic configuration and the second electronic configuration emit distinct wavelengths or electromagnetic fingerprints of radiation. In some embodiments, the radiation is selected from the group consisting of visible, IR and UV radiation. In some embodiments, magnetic resonance imaging is employed to assess the presence of said second electronic configuration.

[0026] In some embodiments, the indicator further comprises liposomes. In some embodiments, the liposomes are pH dependent. For example, the assembled lioposomes may sequester a fluorescent compound and a quencher of the fluorescence of that compound. The liposome is stable in non-acidic pH but disassembles at a sufficiently acidi pH thereby releasing the quencher from close proximity to the fluorescent compound and allowing the fluorescent compound to emit fluorescence. In one embodiment, assembled lioposomes having carboxylic acid groups will disassemble at a lower pH e.g., at or below 5.5.

Conversely, in another embodiment, assembled lioposomes having protonated amino groups are stable at acidic pH but will disassemble at a higher pH. In some embodiments, the indicator is placed ex vivo. In some embodiments, the indicator is placed in vivo.

[0027] In some embodiments, the indicator can be any indicator compound. In some embodiments, the indicator can be a fluorescent indicator e.g., hexamethoxy red or derivatives thereof such as those described in U.S. 8,425,996 which is incorporated herein by reference in its entirety. In some embodiments, the indicator can be any compound of Formula (I), (II), (III) and (IV) as described herein. In some embodiments, the indicator converts between a solid/gel and a liquid in a pH dependent manner.

DETAILED DESCRIPTION OF THE INVENTION

[0028] This invention relates to indicator compounds of Formula (I), (II), (III) and (IV) and polymerizable forms thereof. This invention further relates to implantable medical devices that are covalently attached to indicator compounds of Formula (I), (II), (III) and (IV). The implantable medical devices are capable of self-reporting microbial growth adjacent to or on the implanted device. Before describing this invention in detail the following terms are defined.

Definitions

[0029] "Alkyl" refers to monovalent saturated aliphatic hydrocarbyl groups having from 1 to 10 carbon atoms and, in some embodiments, from 1 to 6 carbon atoms. This term includes, by way of example, linear and branched hydrocarbyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, and neopentyl.

[0030] "C _x -Cy" with respect to a group refers to that group having from x to y carbon atoms.

[0031] "Alkylene" refers to divalent saturated aliphatic hydrocarbyl groups having from 1 to 25 carbon atoms and, in some embodiments, from 1 to 15 carbon atoms. The alkylene groups include branched and straight chain hydrocarbyl groups, such as methylene, ethylene, propylene, 2- methypropylene, pentylene, and the like.

[0032] "Heteroalkylene" refers to alkylene wherein 1-8 carbon atoms, are replaced with a heteroatom, preferably, with one or more of -N(COR')-, -S-, -S(O)-, -S(0 ₂ )-, and -0-, where R ^* is Ci-C ₆ alkyl.

[0033] "Alkoxy" refers to the group -O-alkyl, and includes, by way of example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, t-butoxy, sec-butoxy, and n-pentoxy.

[0034] "Aryl" refers to an aromatic group of from 6 to 14 carbon atoms and no ring heteroatoms and having a single ring (e.g., phenyl) or multiple condensed (fused) rings (e.g., naphthyl or anthryl). For multiple ring systems, the term "Aryl" applies when the point of attachment is at an aromatic carbon atom (e.g., 5,6,7,8 tetrahydronaphthalene-2-yl is an aryl group as its point of attachment is at the 2-position of the aromatic phenyl ring).

[0035] "Heteroaryl" refers to an aromatic group of from 5 to 14 ring atoms and 1-3 ring heteroatoms selected preferably from N, O, S, and P and oxidized forms of N, S, and P and having a single ring (e.g., furyl) or multiple condensed (fused) rings (e.g., benzofuryl). For multiple ring systems, the term "heteroaryl" applies when the point of attachment is at an aromatic ring atom containing at least one heteroatom.

[0036] "Aryloxy" refers to the group -O-Aryl.

[0037] "Halo" refers to F, CI, Br, and/or I.

[0038] "Heteroatom" refers to nitrogen, sulfur, phosphorous, an oxidized forms thereo, and/or oxygen. [0039] "Pg" refers to a protecting group. Protecting group are well known functional groups that when bound to a functional group, render the resulting protected functional group inert to the reaction to be conducted on other portions of the compound and the

corresponding reaction condition, and which can be reacted to regenerate the original functionality under deprotection conditions. The protecting group is selected to be compatible with the remainder of the molecule. An -O-Pg or -S-Pg group protects a hydroxyl or thiol functionality during the synthesis described here. Examples of hydroxyl protecting groups include, for instance, ethers such as benzyl, p-methoxybenzyl, p- nitrobenzyl, allyl, and trityl; dialkylsilylethers, such as dimethylsilyl ether, and trialkylsilyl ethers such as trimethylsilyl ether, triethylsilyl ether, and t-butyldimethylsilyl ether; esters such as benzoyl, acetyl, phenylacetyl, formyl, mono-, di-, and trihaloacetyl such as chloroacetyl, dichloroacetyl, trichloroacetyl, trifluoroacetyl; and carbonates such as methyl, ethyl, 2,2,2-trichloroethyl, allyl, and benzyl. Examples of thiol protecting groups include, for instance, ethers such as z ^' so-propyl, tert-butyl, 2-cyanoethyl, benzyl or substituted benzyl thio ethers, thioesters and thiocarbonates. Additional examples of hydroxy and thiol protecting groups are found in standard reference works such as Greene and Wuts, Protective Groups in Organic Synthesis., 2d Ed., 1991, John Wiley & Sons, and McOmie Protective Groups in Organic Chemistry, 1975, Plenum Press. Methods for protecting and deprotecting hydroxyl and thiol groups disclosed herein can be found in the art, and specifically in Greene and Wuts, supra, and the references cited therein.

[0040] "Leaving group" i.e., LG refers to a moiety that can be replaced by a nucleophile. Examples of leaving groups include but are not limited to halo, sulfonates and Ar _F (e.g., a pentafluoro or tetrafluoro phenyl group).

[0041] As used herein, a "reactive group" refers to a group that can react with an electrophile or a nucleophile, preferably readily, to form a covalent linkage. Non-limiting examples include an epoxide, alkyl-LG, -N=C=0, N=C=S, C0 ₂ LG, azide and the like. In some embodiments, the LG is Ar _F . Leaving groups other than -OAr _F are well known to the skilled artisan and useful herein, and will be apparent to the skilled artisan upon reading this disclosure.

[0042] As used herein, a "polymerizable group" preferably refers to a group that includes an alkene or alkyne group e.g., vinyl or allyl, that is polymerized under various well known condition with monomers containing a alkene or alkyne group. Other polymerizable groups are well known to the skilled artisan and will be apparent to them upon reading this disclosure.

[0043] In some embodiments the polymerizable group is converted to a reactive group by synthetic methods well known to the skilled artisan. For example, in one embodiment, the indicator compound of Formula (I), (II), (III) or (IV) includes one or more substituents R ⁴ where R ⁴ is or includes a polymerizable group, such as an allyl group, that is converted over several steps as outlined in the scheme below to a reactive group, such as an isocyanate group, by synthetic methods well known to the skilled artisan.

[0044] The term "pharmaceutically acceptable salt" refers to a salt that is pharmaceutically acceptable.

[0045] The term "tautomer" includes two or more interconvertable compounds resulting from at least one formal migration of a hydrogen atom and at least one change in valency (e.g., a single bond to a double bond or vice versa). The exact ratio of the tautomers depends on several factors, including temperature, solvent, and pH. Tautomerizations (i.e., the reaction providing a tautomeric pair) may be catalyzed by acid or base. Exemplary tautomerizations include keto-to-enol tautomerizations.

[0046] The term "salt" refers to an ionic compound formed between an acid and a base. When the compound provided herein contains an acidic functionality, such salts include, without limitation, alkai metal, alkaline earth metal, and ammonium salts. As used herein, ammonium salts include, salts containing protonated nitrogen bases and alkylated nitrogen bases. Exemplary, and non-limiting cations useful in pharmaceutically acceptable salts include Na, K, Rb, Cs, NH ₄ , Ca, Ba, imidazolium, and ammonium cations based on naturally occurring amino acids. When the compounds provided and/or utilized herein contain basic functionality, such salts include, without limitation, salts of organic acids, such as caroboxylic acids and sulfonic acids, and mineral acids, such as hydrogen halides, sulfuric acid, phosphoric acid, and the likes. Exemplary and non-limiting anions useful in pharmaceutically acceptable salts include oxalate, maleate, acetate, propionate, succinate, tartrate, chloride, sulfate, bisulfate, mono-, di-, and tribasic phosphate, mesylate, tosylate, and the like.

[0047] The term "signal" refers to any signal that can be detected directly or remotely which signal correlates to the presence of active microbial growth (infection) at or adjacent to the site of a surface wound or internally such as at the site of an implantation of the medical device. The signal can be a color change which can be detected by an indicator attached to the medical device. In one embodiment, the indicator emits information (typically in the form of readable electromagnetic energy) which can be detected ex vivo. Preferably, the signal is directly in the form of electromagnetic energy which penetrates out of the body and can be ascertained by merely monitoring for that energy.

[0048] The term "ex vivo" refers to monitoring or assessment of a signal emitted from the indicator or reporter of the invention located inside the body of a patient using equipment or devices outside the body. That is to say, the signal can be monitored without invasive procedures.

[0049] The term "detecting" refers to the use of any device which can determine the presence of a signal. In an embodiment, the signal is monitored continuously such that a machine-readable signal is detected and reported on an on-going basis. In an embodiment, the signal is detected and monitored intermittently, for example periodically every few hours or days. In an embodiment, the signal is detected at discrete times, for example when infection is suspected or when the patient visits a health care facility (e.g., routine check-ups).

[0050] The term "electromagnetic energy" refers to any wavelength of energy capable of being transmitted from the body as well as being monitored ex vivo. Examples of such energy include light in the ultraviolet (UV), visible and infrared (IR) portions of the light spectrum. Other examples include energy readable by magnetic resonance imaging (MRI), X-rays, and the like.

[0051] The term "produce or can be induced to produce a signal" means that the indicator directly or indirectly produces a signal. An example of indirect production of a signal is the use of energy directed to the indicator to induce fluorescence. [0052] The term "blue light" refers to light that has a wavelength of about 450-500 nm and is more energetic than red light which has a wavelength of about 620 to 750 nm. Blue light penetrates skin well and frequently is used to treat jaundice in newborns by breaking down bilirubin in the blood. In this invention, irradiation of an implanted medical device having covalently bound thereto HMR will allow absorption of the blue light and emittance of fluorescence if there is an active infection.

[0053] The term "patient" refers to any mammalian patient and includes without limitation primates such as humans, monkeys, apes, and the like, and domesticated animals such as horses, dogs, cats, ovines, bovines, and the like.

[0054] In one aspect, provided herein are compounds of Formulas (I), (II), (III) and (IV):

(III)

pharmaceutically acceptable salt thereof, wherein

each of p, q, and r independently is 0, 1 or 2; R ¹ , R ² and R ³ independently are hydrogen, Pg, L-R ⁴ , Ci-C ₆ alkyl, C ₃ -C ₈ cycloalkyl, or phenyl, each of which are optionally substituted with 1-5, preferably, 1-3 substituents selected from the group consisting of halo, preferably fluoro, cyano, Ci-C ₆ alkoxy, and aryloxy;

R ⁴ is a polymerizable group or a reactive group;

6 7 8 9 28 29

R , R , R , R , R and R independently are hydrogen or Ci-C ₆ alkyl, optionally substituted with or L-R ⁴ ;

each X independently is:

-OR ³ ;

L-R ⁴ ;

Ci-C ₆ alkyl, C ₁ -C ₁ 0 heteroalkyl, C ₃ -C ₈ cycloalkyl or C ₃ -C ₈ heterocyclyl,

optionally substituted with 1-3 phenyl, oxo, cyano, halo, nitro;

C ₆ -Cio aryl or C ₂ -C ₁ 0 heteroaryl having 1-6 ring heteroatoms selected

preferably from N, O, S, and P and oxidized forms of N, S, and P, wherein the aryl or heteroaryl is optionally substituted with 1-4, preferably 1-3, more preferably 1-2, and still more preferably 1 substituent, wherein the substituent is selected from the group consisting of alkyl, preferably Ci-C ₆ alkyl, -OR ¹⁸ , wherein R ¹⁸ is alkyl, preferably Ci-C ₆ alkyl, C ₃ -C ₈ cycloalkyl, C6-C10 aryl, preferably phenyl, each of which are optionally substituted with 1-5, preferably, 1-3 substituents selected from the group consisting of halo, preferably fluoro, cyano, Ci-C ₆ alkoxy, and aryloxy;

cyano, halo, nitro; -C0 ₂ H, -C0 ₂ d-C ₆ alkyl, -C0 ₂ -C ₆ -Cio aryl, SR ³ ; -

CONR ²⁸ R ²⁹ or -S0 ₂ NR ²⁸ R ²⁹ ; or two adjacent X substituents may combine with the carbon atoms to which they are joined to form an C ₆ - C ₁ 0 aryl heterocyclic, C ₃ -Cg cycloalkyl, or C ₃ -Cg heterocyclyl ring;

Z is C or S;

v is 1 if Z is C, and v is 1 or 2 if Z is S;

A is an anionic counterion;

Pg is a hydroxyl protecting group;

L is a covalent bond or a linker which joins the one or more polymerizable groups or reactive groups to the oxygen atom to which it is attached;

provided that: the compound of Formula (I) is not o-cresolphthalein, phenolphthalein, thymolphthalein, guaiacolphthalein, a-naphtholphthalein, tetrabromophenolphthalein or xylenolphthalein;

the compound of Formula (II) is not phenol red, o-cresol red, thymol blue, m-cresol purple, chlorophenol red, bromophenol red, bromophenol blue, bromoxylenol blue, bromocresol purple or xylenol blue;

the compound of Formula (III) is not alizarin red; and

the compound of Formula (IV) is not a-dinitrophenol, β-dinitrophenol, γ- dinitrophenol, ε-dinitrophenol, δ-dinitrophenol, o-nitrophenol, m-nitrophenol, p-nitrophenol or picric acid.

[0055] In some embodiments, at least one of R and R ² is L-R ⁴ , and/or p + q + r is at least 1 and X is -OL-R ⁴ .

[0056] In one embodiment, provided herein is a compound of Formula (I):

(I)

or a pharmaceutically acceptable salt or tautomer thereof, wherein

each of p, q, and r independently are, 0, 1 or 2,

R ²⁸ and R ²⁹ are independently hydrogen or Ci-C ₆ alkyl, optionally substituted with or L-R ⁴ ;

Z is -C0 ₂ H or -S0 ₃ H; and

the remaining variables are as described herein; provided that the compound of Formula (I) is not o-cresolphthalein, phenolphthalein, thymolphthalein, guaiacolphthalein, a-naphtholphthalein, tetrabromophenolphthalein or xylenolphthalein.

[0057] In some embodiments, the compound of Formula (I) is a compound of Formula (la):

(la) or a pharmaceutically acceptable salt or tautomer thereof, wherein the remaining variables are as defined for the compound of Formula (I).

[0058] In some embodiments, the compound of Formula (I) is a compound of Formula (lb):

(lb) or a pharmaceutically acceptable salt or tautomer thereof, wherein the remaining variables are as defined for the compound of Formula (I). [0059] In some embodiments Z is C. In some embodiments Z is S. In some embodiments v is 1. In some embodiments v is 2.

[0060] In some embodiments, at least one of R ¹ and R ² is L-R ⁴ .

[0061] Suitable compounds of Formula (I) include phthaleins or phthalic anhydrides of Formula (Ic) and sulfonephthaleins of Formula (Id).

Phthaleins or Phthalic Anhydride pH Indicators:

(Ic)

[0062] For example, suitable phthalic anhydrides Formula (Ic) include but are not limited to phthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, 5-nitrophthalic anhydride, 6-nitrophthalic anhydride, 3-chlorophthalic anhydride, 4-chlorophthalic anhydride, 5-chlorophthalic anhydride, 6-chlorophthalic anhydride, 3-bromophthalic anhydride, 4-bromophthalic anhydride, 5-bromophthalic anhydride, 6-bromophthalic anhydride, 3-iodophthalic anhydride, 4-iodophthalic anhydride, 5-iodophthalic anhydride, 6- iodophthalic anhydride, 3-fluorophthalic anhydride, 4-fluorophthalic anhydride, 5- fluorophthalic anhydride, 6-fluorophthalic anhydride, 3-methylphthalic anhydride, 4- methylphthalic anhydride, 5-methylphthalic anhydride, 6-methylphthalic anhydride, 3- ethylphthalic anhydride, 4-ethylphthalic anhydride, 5 -ethylphthalic anhydride, 6- ethylphthalic anhydride, 3 -methoxyphthalic anhydride, 4-methoxyphthalic anhydride, 5- methoxyphthalic anhydride, 6-methoxyphthalic anhydride, 3-cyanophthalic anhydride, 4- cyanophthalic anhydride, 5-cyanophthalic anhydride, 6-cyanophthalic anhydride, 3- aminophthalic anhydride, 4-aminophthalic anhydride, 5-aminophthalic anhydride, 6- aminophthalic anhydride, 3-acetamidophthalic anhydride, 4-acetamidophthalic anhydride, 5- acetamidophthalic anhydride, 6-acetamidophthalic anhydride, 3,4,5,6-tetrachlorophthalic anhydride, 3,4,5,6-tetrabromophthalic anhydride, 3,4,5,6-tetraiodophthalic anhydride, 3,4,5,6-tetrafluorophthalic anhydride, 3,4,5,6-tetranitrophthalic anhydride, 3,4,5,6- tetramethylphthalic anhydride, 3,4,5,6-tetraethylphthalic anhydride, 3,4,5,6- tetramethoxyphthalic anhydride, 3,4,5,6-tetracyanophthalic anhydride, 3,4,5,6- tetraaminophthalic anhydride, 3,4,5,6-tetraacetamidophthalic anhydride, naphthalic anhydride, 2-chloronaphthalic anhydride, 3-chloronaphthalic anhydride, 4-chloronaphthalic anhydride, 5-chloronaphthalic anhydride, 6-chloronaphthalic anhydride, 7-chloronaphthalic anhydride, 2-bromonaphthalic anhydride, 3-bromonaphthalic anhydride, 4-bromonaphthalic anhydride, 5-bromonaphthalic anhydride, 6-bromonaphthalic anhydride, 7-bromonaphthalic anhydride, 2-iodonaphthalic anhydride, 3-iodonaphthalic anhydride, 4-iodonaphthalic anhydride, 5-iodonaphthalic anhydride, 6-iodonaphthalic anhydride, 7-iodonaphthalic anhydride, 2-fluoronaphthalic anhydride, 3-fluoronaphthalic anhydride, 4-fluoronaphthalic anhydride, 5-fluoronaphthalic anhydride, 6-fluoronaphthalic anhydride, 7-fluoronaphthalic anhydride, 2-nitronaphthalic anhydride, 3-nitronaphthalic anhydride, 4-nitronaphthalic anhydride, 5-nitronaphthalic anhydride, 6-nitronaphthalic anhydride and 7-nitronaphthalic anhydride.

[0063] The term "phthalic anhydride equivalent" is intended to include those compounds of Formula (Ic) where, two adjacent X substituents, for example, combine to form an aromatic, heterocyclic, or non-aromatic ring. Suitable compounds include naphthols for example.

[0064] Representative color changes for selected phthalein compounds of Formula (Ic) are shown below.

Table 1

Sulfonephthalem pH Indicators:

(Id)

[0065] The sulfonephthalem pH indicators are closely related to phthaleins but the carboxylic acid group in phthaleins is merely replaced by sulfonic acid group. Representative color changes for selected sulfonephthalem compounds of Formula (Id) are shown below.

Table 2

[0066] In another embodiment, provided herein is a compound of Formula (II):

NR ⁶ R ⁷

(Π) or a pharmaceutically acceptable salt or tautomer thereof,

wherein

each of p, q, and r independently are, 0, 1 or 2, and p+q+r is at least 1;

R 6 , R 7 , R 8 , R 9 , R 28 and R 29 are independently hydrogen or Ci-C ₆ alkyl, optionally substituted with or L-R ⁴ ;

A is an anionic counterion, preferably CI or OAc; and

the remaining variables are as described herein;

provided that the compound of Formula (II) is not phenol red, o-cresol red, thymol blue, m-cresol purple, chlorophenol red, bromophenol red, bromophenol blue, bromoxylenol blue, bromocresol purple or xylenol blue.

[0067] In some embodiments, the compound of Formula (II) is a compound of Formula (Ila):

NR ⁶ R ⁷

(Ila) or a pharmaceutically acceptable salt or tautomer thereof, wherein the remaining variables are as defined for the compound of Formula (II).

[0068] The inclusion of one or more substituents "X" on the phenyl ring(s) in the compounds of Formulas (I) and (II) allows for modulating the pKa of the indicator or for modulating the stability of the conjugated ring systems of Formula (I) or (II), or the trisubstituted methyl cation formed, in a manner consistent with the pH desired for color transformation of the indicator.

[0069] A nonlimiting process of water elimination and color generation is schematically depicted below:

wherein each Ar of the schemes shown above independently refers to aryl moieties shown in the compounds provided herein, for example, of Formulas (I) and (II). That is to say that introducing an electron donating and/or a cation stabilizing substituent such as, without limitation, alkoxy, alkyl, and aryl, provide an indicator, which changes color at lower acidity and higher pH. On the other hand, introducing an electron withdrawing substituent such, without limitation, halo or cyano, will provide for an indicator, which changes color at higher acidity and lower pH.

[0070] In one embodiment, provided herein is a compound of Formula (III):

or a pharmaceutically acceptable salt or tautomer thereof,

wherein

each of p and q independently are, 0, 1 or 2, and p+q is at least 1 ;

R ²⁸ and R ²⁹ are independently hydrogen or Ci-C ₆ alkyl, optionally substituted with or L-R ⁴ ; and

the remaining variables are as described herein;

provided that the compound of Formula (III) is not alizarin red. [0071] In one embodiment, provided herein is a compound of Formula (IV):

(IV) or a pharmaceutically acceptable salt or tautomer thereof,

wherein

p is 1 or 2;

R ²⁸ and R ²⁹ are independently hydrogen or Ci-C ₆ alkyl, optionally substituted with or L-R ⁴ ; and

the remaining variables are as described herein;

provided that the compound of Formula (IV) is not a-dinitrophenol, β-dinitrophenol, γ-dinitrophenol, ε-dinitrophenol, δ-dinitrophenol, o-nitrophenol, m- nitrophenol, p-nitrophenol or picric acid.

[0072] Representative compounds of Formula (IV) are provided below in Table 3.

Table 3

[0073] In some embodiments, for the compound of Formula (I), (II), (III) or (IV), p is 0. In some embodiments p is 1. In some embodiments p is 2. In some embodiments q is 0. In some embodiments q is 1. In some embodiments q is 2. In some embodiments r is 0. In some embodiments r is 1. In some embodiments r is 2.

[0074] In some embodiments, for the compound of Formula (I), (II), (III) or (IV), X is Ci- C ₆ alkyl, optionally substituted. In some embodiments, X is Ci-Cio heteroalkyl, optionally substituted. In some embodiments, X is C3-C8 cycloalkyl, optionally substituted. In some embodiments, X is C ₃ -C ₈ heterocyclyl, optionally substituted.

[0075] In another embodiment, for the compound of Formula (I), (II), (III) or (IV), at least one X group is Ci-C ₆ alkyl. In another embodiment, at least two X groups are Ci-C ₆ alkyl. In another embodiment, at least three X groups are Ci-C ₆ alkyl. In another embodiment, at least four X groups are Ci-C ₆ alkyl. In some embodiments, the Ci-C ₆ alkyl group is methyl. In some embodiments, the Ci-C ₆ alkyl group is ethyl. In some embodiments, the Ci-C ₆ alkyl group is iso-propyl.

[0076] In some embodiments, for the compound of Formula (I), (II), (III) or (IV), X is C ₆ - C10 aryl, optionally substituted. In some embodiments, X is or C ₂ -Ci ₀ heteroaryl, optionally substituted.

[0077] In some embodiments, for the compound of Formula (I), (II), (III) or (IV), X is - OR ³ . In some embodiments, for the compound of Formula (I), (II), (III) or (IV), X is L-R . In some embodiments, X is or C ₂ -Ci ₀ heteroaryl, optionally substituted. In some

embodiments, X is -SR ³ . In some embodiments, R ³ is hydrogen. In some embodiments, R ³ is Ci-C ₆ alkyl. In some embodiments, R ³ is C ₃ -Cg cycloalkyl, optionally substituted. In some embodiments, R ³ is phenyl, optionally substituted. In some embodiments, R ³ is Pg. In some embodiments, R ³ is L-R ⁴ . In some embodiments, R ³ is cyano. In some embodiments, R ³ is halo. In some embodiments, R ³ is nitro. In some embodiments, R ³ is -C0 ₂ _Ci-C ₆ alkyl. In

3 3 28 29 some embodiments, R is -C0 ₂ _C ₆ -Cio aryl. In some embodiments, R ^J is -CONR" ⁰ R^. In

3 28 29 28 29

some embodiments, R ^J is -S0 ₂ NR^R^. In some embodiments, R and R are methyl.

[0078] In some embodiments, for the compound of Formula (I), (II), (III) or (IV), R ⁶ , R ⁷ , R ⁸ , and R ⁹ are hydrogen. In some embodiments, R ⁶ , R ⁷ , R ⁸ , and R ⁹ are Ci-C ₆ alkyl. In some embodiments, R ⁶ , R ⁷ , R ⁸ , and R ⁹ are Ci-C ₆ alkyl substituted with or L-R ⁴ . [0079] In some embodiments, for the compound of Formula (I), (II), (III) or (IV), R ⁴ is selected from the group consisting of-NCO, -NCS, -N ₃ , ethynyl, -C0 ₂ R ^u ,

R is selected from the group consisting of hydrogen, C0 ₂ H, C0 ₂ R , CN, and

CON(R ¹³ ) ₂ ;

R ¹¹ is a phenyl substituted with 4 or 5 fluoro atoms, or is succinimidyl or

phthalimidyl;

R ¹² is Ci-Ci ₂ alkyl optionally substituted with 1-3 hydroxy groups;

R ¹³ Ci-Ci ₂ alkyl optionally substituted with 1-3 hydroxy groups or the 2 R ¹³ groups together with the nitrogen atoms they are bound to form a 5-7 membered heterocyclic ring having 1 to 3 heteroatoms selected from oxygen, sulfur, nitrogen or NR ¹⁴ where R ¹⁴ is hydrogen or C _\ -Cn alkyl; and

R ¹⁵ is selected from the group consisting of hydrogen, Ci-C ₆ alkyl optionally substituted with 1-3 hydroxy groups, and CN.

[0080] In another embodiment, for the compound of Formula (I), (II), (III) or (IV), L is Ci- C ₂ o alkylene or heteroalkylene having 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen, each of which is optionally substituted with 1-10 substituents selected from the group consisting of oxo (=0), thio (=S), and Ci-C ₆ alkyl. Non-limiting examples of alkylene include -(CH ₂ ) _n - where n is 1-12. In another embodiment, L is a covalent bond.

[0081] In another embodiment, for the compound of Formula (I), (II), (III) or (IV), L-R ⁴ groups are vinyl or allyl. In another embodiment, L-R ⁴ groups are -(CH ₂ ) _m - OCOC(Me)=CH ₂ . In another embodiment, L-R ⁴ groups are -(CH ₂ ) _m -OCOCH=CH ₂ . Such groups will result in the formation of an ethylene, propylene, or another higher alkylene group covalently attached at one end to the remainder of the indicator and at the other end to the polymeric chain. A polymerizable group, such as an acrylate or a methacrylate, is contemplated to polymerize the compounds of this invention with another monomer such as hydroxyethyl methacrylate. The inclusion of such polymerizable groups and L-R ⁴ should minimally alter the pKa of the indicator. That is to say that the pKa should change by no more than ± 0.5, preferably by no more than ± 0.3, and even preferably by no more than ± 0.2 units.

[0082] In some embodiments, each R ¹ , R ² and R ³ independently is methyl, vinyl, allyl, - (CH ₂ ) _m -OCOCH=CH _2, or -(CH ₂ ) _m -OCOC(Me)=CH ₂ , provided that at least one of R ¹ , R ² and R ³ is not methyl.

[0083] In some embodiments, 1, 2, or 3 of R ¹ , R ² and R ³ are -(CH ₂ ) _m -OCOC(Me)=CH ₂ .

[0084] The term "phenol equivalent" is intended to include those compounds where, as described above, two adjacent X substituents, for example, combine to form an aromatic, heterocyclic, or non-aromatic ring. Suitable compounds include naphthols for example.

Synthetic Methods

[0085] The compounds of this invention are synthesized following art recognized methods with the appropriate substitution of commercially available reagents as needed. Other compounds are synthesized following modifications of the methods illustrated herein, and those known, based on this disclosure. See, for example, Raj. B. Durairaj, Resorcinol:

Chemistry, Technology, and Applications, Birkhauser, 2005. Illustrative and non- limiting methods for synthesizing the compounds of this invention are schematically shown below.

[0086] Phthalein pH Indicators of Formula (I): A typical synthesis of phthalein pH indicators of formula (If) is depicted in the scheme below, wherein 2 equivalents of a phenol or phenol equivalent are condensed with 1 equivalent of a phthalic anhydride or equivalent under essentially acid anhydrous conditions.

[0087] Generally, the phenol and anhydride are condensed in the presence of an acid under anhydrous conditions. For example, polyphosphoric acid and zinc chloride can be utilized. The carbon atom at the 4-position with respect to the aromatic hydroxyl group is generally not substituted as it is necessary for the reaction. Polyphosphoric acid can act as a condensing agent as well as reaction medium. The reaction with only polyphosphoric acid afforded tarry products but when a very small amount of zinc chloride was added to polyphosphoric acid, clean product was isolated. Very small amount of zinc chloride was found to increase yield and purity of the product. Polyphosphoric acid can be replaced with orthophosphoric acid, chlorosulfonic acid, methane sulfonic acid, trifluoroacetic acid or other acids under anhydrous conditions. Suitable solvents include non-protic solvents known in the art such as tetrahydrofuran, dioxane, methylene chloride, ether, etc.

[0088] The reaction proceeds with the formation of an isobenzofuranone (If), which is then treated with a base under aqueous conditions. The salt can be isolated or the solution can be acidified to produce the protonated phenol/carboxylic acid. For example, one molar equivalent of (If) was condensed with either two molar equivalent of sodium hydroxide in 85% ethanol or two molar equivalent of sodium ethoxide in ethanol. The products are generally solids and can be easily purified via filtration, crystallization, and other methods known in the art.

[0089] Suitable phenols include, but are not limited to 2-nitrophenol, 3-nitrophenol, 2- chlorophenol, 3-chlorophenol, 2-bromophenol, 3-bromophenol, 2-iodophenol, 3-iodophenol, 2-fluorophenol, 3-fluorophenol, 2-aminophenol, 3-aminophenol, 2-acetamidophenol, 3- acetamidophenol, 2-cyanophenol, 3-cyanophenol, 2-methylphenol, 3-methylphenol, 2- ethylphenol, 3-ethylphenol, 2-proylphenol, 3-proylphenol, 2-isoproylphenol, 3- isoproylphenol, 2-butylphenol, 3-butylphenol, 2-isobutylphenol, 3-isobutylphenol, 2- pentylphenol, 3-pentylphenol 2-hexylphenol, 3-hexylphenol, 2-heptylphenol, 3-heptylphenol, 2-octylphenol, 3-octylphenol, 2-nonylphenol, 3-nonylphenol, 2-decylphenol, 3-decylphenol, 2-decylphenol, 2-methoxyphenol, 3-methoxyphenol, 2-ethoxyphenol, 3-ethoxyphenol, 2- propoxyphenol, 3-propoxyphenol, 2-isopropoxyphenol, 3-isopropoxyphenol, 2- butoxyphenol, 3-butoxyphenol, 2-isobutoxyphenol, 3-isobutoxylphenol, 2-allylphenol, 3- allylphenol, 2-vinylphenol, 3-vinylphenol, 2-phenylphenol, 3-phenylphenol, 2- phenoxyphenol, 3-phenoxyphenol, 2-cyclopropylphenol, 3-cyclopropylphenol, 2- cyclobutylphenol, 3-cyclobutylphenol, 2-cyclopentylphenol, 3-cyclopentylphenol, 2- cyclohexylphenol, 3-cyclohexylphenol, 2-cycloheptylphenol, 3-cycloheptylphenol, 2- cyclooctylphenol, 3-cyclooctylphenol, 2-cyclononylphenol, 3-cyclononylphenol, 2- cyclodecylphenol, 3-cyclodecylphenol, 2,3-dinitrophenol, 2,5-dinitrophenol, 2,6- dinitrophenol, 2,3-dimethylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol, 2,3- diethylphenol, 2,5-diethylphenol, 2,6-diethylphenol, 2,3-diproplylphenol, 2,5-dipropylphenol, 2,6-dipropylphenol, 2,3-diisoproplylphenol, 2,5-diisopropylphenol, 2,6-diisopropylphenol, 2,3-dibutylphenol, 2,5-dibutylphenol, 2,6-dibutylphenol, 2,3-diisobutylphenol, 2,5- diisobutylphenol, 2,6-diisobutylphenol, 2,3-dipentylphenol, 2,5-dipentylphenol, 2,6- dipentylphenol, 2,3-dihexylphenol, 2,5-dihexylphenol, 2,6-dihexylphenol, 2,3- diheptylphenol, 2,5-diheptylphenol, 2,6-diheptylphenol, 2,3-dioctylphenol, 2,5-dioctylphenol, 2,6-dioctylphenol, 2,3-dinonylphenol, 2,5-dinonylphenol, 2,6-dinonylphenol, 2,3- didecylphenol, 2,5-didecylphenol, 2,6-didecylphenol, 2,3-dimethoxyphenol, 2,5- dimethoxyphenol, 2,6-dimethoxyphenol, 2,3-diethoxyphenol, 2,5-diethoxyphenol, 2,6- diethoxyphenol, 2,3-dipropoxyphenol, 2,5-dipropoxyphenol, 2,6-dipropoxyphenol, 2,3- diisopropoxyphenol, 2,5-diisopropoxyphenol, 2,6-diisopropoxyphenol, 2,3-dibutoxyphenol, 2,5-dibutoxyphenol, 2,6-dibutoxyphenol, 2,3-diisobutoxyphenol, 2,5-diisobutoxyphenol, 2,6- diisobutoxyphenol, 2,3-dipentoxyphenol, 2,5-dipentoxyphenol, 2,6-dipentoxyphenol, 2,3- dihexoxyphenol, 2,5-dihexoxyphenol, 2,6-dihexoxyphenol, 2,3-diheptoxyphenol, 2,5- diheptoxyphenol, 2,6-diheptoxyphenol, 2,3-dioctoxyphenol, 2,5-dioctoxyphenol, 2,6- dioctoxyphenol, 2,3-dinonoxyphenol, 2,5-dinonoxyphenol, 2,6-dinonoxyphenol, 2,3- didecyloxyphenol, 2,5-didecyloxyphenol, 2,6-didecyloxyphenol, 2,3-dichlorophenol, 2,5- dichlorophenol, 2,6-dichlorophenol, 2,3-dibromophenol, 2,5-dibromophenol, 2,6- dibromophenol, 2,3-diiodophenol, 2,5-diiodophenol, 2,6-diiodophenol, 2,3-difluorophenol,

2.5- difluorophenol, 2,6-difluorophenol, 2,3-diaminophenol, 2,5-diaminophenol, 2,6- diaminophenol, 2,3-diacetamidophenol, 2,5-diacetamidophenol, 2,6-diacetamidophenol, 2,3- dicyanophenol, 2,5-dicyanophenol, 2,6-dicyanophenol, 2,3-diallylphenol, 2,5-diallylphenol,

2.6- diallylphenol, 2,3-divinylphenol, 2,5-divinylphenol, 2,6-divinylphenol, 2,3- diphenylphenol, 2,5-diphenylphenol, 2,6-diphenylphenol, 2,3-diphenoxyphenol, 2,5- diphenoxyphenol, 2,6-diphenoxyphenol, 2,3-dicycloproylphenol, 2,5-dicyclopropylphenol, 2,6-dicyclopropylphenol, 2,3-dicyclobutylphenol, 2,5-dicyclobutylphenol, 2,6- dicyclobutylphenol, 2,3-dicyclopentylphenol, 2,5-dicyclopentylphenol, 2,6- dicyclopentylphenol, 2,3-dicyclohexylphenol, 2,5-dicyclohexylphenol, 2,6- dicyclohexylphenol, 2,3-dicycloheptylphenol, 2,5-dicycloheptylphenol, 2,6- dicycloheptylphenol, 2,3-dicyclooctylphenol, 2,5-dicyclooctylphenol, 2,6- dicyclooctylphenol, 2,3-dicyclononylphenol, 2,5-dicyclononylphenol, 2,6- dicyclononylphenol, 2,3-dicyclodecylphenol, 2,5-dicyclodecylphenol, 2,6- dicyclodecylphenol, 2,3,5-trimethylphenol, 2,3,6-trimethylphenol 2,3,5-triethylphenol, 2,3,6- triethylphenol, 2,3,5-tripropylphenol, 2,3,6-tripropylphenol, 2,3,5-tributylphenol, 2,3,6- tributylphenol, 2,3,5-trichlorophenol, 2,3,6-trichlorophenol, 2,3,5-tribromophenol, 2,3,6- tribromophenol, 2,3,5-triiodophenol, 2,3,6-triiodophenol, 2,3,5-trifluorophenol, 2,3,6- trifluorophenol, 2,3,5-trivinylphenol, 2,3,6-trivinylphenol, 2,3,5-triallylphenol, 2,3,6- triallylphenol, 2,3,5-triphenylphenol, 2,3,6-triphenylphenol, 2,3,5-triphenoxyphenol, 2,3,6- triphenoxyphenol, 2,3,5-trimethoxyphenol, 2,3,6-trimethoxyphenol, 2,3,5-triethoxyphenol, 2,3,6-triethoxyphenol, 2,3,5-tripropoxyphenol, 2,3,6-tripropoxyphenol, 2,3,5- tributoxyphenol, 2,3,6-tributoxyphenol, 2,3,5-trinitrophenol, 2,3,6-trinitrophenol, 2,3,5- triaminophenol, 2,3,6-triaminophenol, 2,3,5-triacetamidophenol, 2,3,6-triacetamidophenol, 2,3,5-tricyanophenol, 2,3,6-tricyanophenol, 3-(N,N-diethylamino)phenol, 2-tert-butyl-5- methylphenol, 2-tert-butyl-6-methylphenol, 3-methyl-2-nitrophenol, 5-methyl-2-nitrophenol,

6- methyl-2-nitrophenol, 3-ethyl-2-nitrophenol, 5-ethyl-2-nitrophenol, 6-ethyl-2-nitrophenol, 3-methoxyl-2-nitrophenol, 5-methoxy-2-nitrophenol, 6-methoxy-2-nitrophenol, 1-naphthaol, 2-naphthaol, 2-nitro-l -naphthol, 3-nitro-l -naphthol, 5 -nitro-1 -naphthol, 6-nitro-l -naphthol,

7- nitro-l-naphthol, 8-nitro-l -naphthol, 2-methyl-l -naphthol, 3-methyl-l -naphthol, 5-methyl- 1 -naphthol, 6-methyl-l -naphthol, 7 -methyl- 1 -naphthol, 8-methyl-l -naphthol, 2-methoxy-l- naphthol, 3-methoxy-l -naphthol, 5-methoxy-l -naphthol, 6-methoxy-l -naphthol, 7-methoxy- 1 -naphthol, 8-methoxy-l -naphthol, 2-chloro-l -naphthol, 3-chloro-l -naphthol, 5-chloro-l- naphthol, 6-chloro-l -naphthol, 7-chloro-l -naphthol, 8-chloro-l -naphthol, 2-bromo-l- naphthol, 3-bromo-l -naphthol, 5-bromo-l -naphthol, 6-bromo-l -naphthol, 7-bromo-l- naphthol, 8-bromo-l -naphthol, 2-iodo-l -naphthol, 3 -iodo-1 -naphthol, 5-iodo-l -naphthol, 6- iodo-1 -naphthol, 7-iodo-l -naphthol, 8-iodo-l -naphthol, 2-fluoro-l -naphthol, 3-fluoro-l- naphthol, 5 -fluoro-1 -naphthol, 6-fluoro-l -naphthol, 7-bromo-l -naphthol, 8-fluoro-l- naphthol, 2-cyano-l-naphthol, 3-cyano-l-naphthol, 5-cyano-l-naphthol, 6-cyano-l-naphthol, 7-cyano-l -naphthol, 8-cyano-l -naphthol, 8 -hydroxy quinaldine and 2-quinoxalinol.

[0090] Compounds of Formula (II) can be prepared, according to known methods, by the condensation of benzaldehyde derivatives and dimethylaniline derivatives to give leuco malachite green derivatives:

[0091] Other compounds of this invention, for example, those including one or more heteroaryl rather than substituted or unsubstituted phenyl rings, are prepared following methods well known to the skilled artisan, or following methods illustrated here, upon appropriate substitution of starting material and reaction conditions as will be apparent to the skilled artisan upon reading this disclosure.

[0092] Other compounds of this invention are conveniently synthesized following these and other known methods upon appropriate substitution of starting material and, if needed, protecting groups. Electron withdrawing substituents such as halo can be conveniently incorporated into the aryl rings by electrophilic substitution employing hypohalite, halogens, ICl, preferably under alkaline conditions. A halo group is conveniently converted to a cyano group following well known methods, such as those employing CuCN. A nitro group is conveniently incorporated by electrophilic nitration employing various conditions and reagents well known to the skilled artisan, such as nitronium tetrafluoroborate, nitric acid, optionally with acetic anhydride, and the likes.

[0093] The reactions are carried out, preferably in an inert solvent, for a period of time sufficient to provide a substantial amount of the product, which is detected following well known methods such as thin layer chromatography or ¹ H-nuclear magnetic resonance spectrometry. The products are used for the subsequent steps without further purification or can be purified following well known methods such as one or more of column

chromatography, crystallization, precipitation, and distillation under reduced pressure.

[0094] Other compounds of this invention are prepared following methods well known to a skilled artisan and/or those disclosed herein upon appropriate substitution of reactants and reagents.

[0095] It is contemplated that the pH sensitivity of some of the compounds of Formulas (I)- (IV) is within ±0.5, preferably, within ±0.3, more preferably within ±0.2 of that of, for example, hexamethoxy red. It is also contemplated that pH sensitivity of the compounds of Formula (I), wherein R ¹ is -OR ⁸ , is within ±0.5, preferably, within ±0.3, more preferably within ±0.2 of that of heptamethoxy red.

Polymers and Co-polymers

[0096] As used herein, "polymers" and co-polymers" provided herein do not include polymers or co-polymers created by substitution of a substitution. Should such substitution of substitution give rise to potential polymers or co-polymers, such substitution is limited to 3 such substitutions.

[0097] In another aspect, the invention provides polymers which contain an indicator compound of Formulas (I), (II), (III) and (IV), or reaction products therefrom, covalently bound to the polymer, wherein sufficient indicator is bound to the polymer such that the color of the polymer is changed from transparent at neutral pH to colored at acidic pH. In one aspect, a polymer or co-polymer is provided, comprising an indicator compound of Formulas (I), (II), (III) and (IV), or reaction products therefrom, covalently bound to the polymer or copolymer. In some embodiments, the polymer or co-polymer comprises a biodegradable material such as hyaluronic acid, collagen, polylactides, polyglycolides, polycaprolactones, polydioxanones, polycarbonates, polyhydroxybutyrates, polyalkylene oxalates,

polyanhydrides, polyamides, polyesteramides, polyurethanes, polyacetals, polyketals, polyorthocarbonates, polyphosphazenes, polyhydroxyvalerates, polyalkylene succinates, poly(malic acid), poly(amino acids), chitin, chitosan, and polyorthoesters, and copolymers, terpolymers and combinations and mixtures thereof. See, for example, Dunn, et al., US Patent No. 4,938,763 which is incorporated herein by reference in its entirety.

Implantable Medical Devices

[0098] As used herein, an "implantable medical device" refers to any type of medical device that is totally or partly introduced, surgically or medically, into a patient's body or by medical intervention into a natural orifice, and which is intended to remain there after the procedure. The medical device may be a probe which is used on an immediate basis to determine if there is an active infection at the site to be probed. In such cases, the probe can be used to transmit electromagnetic signals to provide evidence of infection including a color change, fluorescence, and the like. Alternatively, the duration of implantation may be essentially permanent, i.e., intended to remain in place for the lifespan of the product or patient; or until it is physically removed or biodegrades. Examples of essentially permanent implantable medical devices include, without limitation, implantable cardiac pacemakers and defibrillators; leads and electrodes for the preceding; implantable organ stimulators such as nerve, bladder, sphincter and diaphragm stimulators; cochlear implants; prostheses, including artificial knees, hips, and other joint replacements; vascular grafts, self-expandable stents, balloon-expandable stents, stent-grafts, grafts, artificial heart valves, cerebrospinal fluid shunts; renal dialysis shunts; artificial hearts; implantable infusion pumps; breast implants; dental implants; surgical mesh; and implantable access systems.

[0099] Alternatively, the duration of the implant may be temporary. That is to say that the implant is intended to remain in place for a defined period of time which, however, is sufficient to allow an infection to develop. Temporary implants may be inserted from 1 day through 2 years or longer. Examples of temporary implants include sutures, catheters, intravenous injection ports, braces, and the like.

[0100] The term "surface" as it relates to the implantable medical device refers to the outer surface of the device interfacing with physiological fluid and tissue or organs of a patient. As described below, in a preferred embodiment, the surface of the medical device comprises a surface layer to which an indicator or reporter has been integrated therein or can be attached by post-treatment to from covalent linkages thereto. In an embodiment, the surface comprises a mesh or similar covering, for example the surgical mesh pouches disclosed in PCT Pub. No. WO 2008/127411. In yet another embodiment, the surface comprises a biodegradable or bioerodable layer which covers and thereby protects the indicators and/or reporters during implantation. In such an embodiment, the surface of the medical device constitutes three components - the inner component defining the surface of the medical device; an

intermediate component which is a plurality of indicators and/or reporters bound to the medical device surface; and an outer component which is a biodegradable or bioerodable layer forming the outer surface.

[0101] The term "biodegradable or bioerodable layer" refers to a biocompatible material, such as those described herein, which degrades or erodes in vivo to expose the underlying surface. Such materials can be any material well known in the art which provides for an outer coating on the device.

[0102] In another aspect, the invention provides an implantable medical devices that, in addition to their therapeutic functions (e.g., as a prosthetic joint), are capable of indicating the presence of infection adjacent to or on a medical device implanted in a patient. The implantable medical devices of the invention are covalently bound to one or more compounds of formulas (I)-(IV). In some embodiments, the implantable medical device is covalently bound to one compound of formulas (I)-(IV). In some embodiments, the implantable medical device is covalently bound to more than one compound of formulas (I)-(IV). In some embodiments, the implantable medical device is covalently bound to two compounds of formulas (I)-(IV). In some embodiments, the implantable medical device is covalently bound to three compounds of formulas (I)-(IV). In some embodiments, the implantable medical device is covalently bound to one or more compounds of formulas (I). In some

embodiments, the implantable medical device is covalently bound to one or more compounds of formulas (II). In some embodiments, the implantable medical device is covalently bound to one or more compounds of formulas (III). In some embodiments, the implantable medical device is covalently bound to one or more compounds of formulas (IV).

[0103] In some embodiments, the surface of the implantable medical device and the one or more compounds of formulas (I)-(IV), both having compatible functional groups as described herein, are contacted under suitable conditions for the compatible functional groups to react and form covalent bonds between the surface of the implantable medical device and the one or more compounds of formulas (I)-(IV). As such, the one or more compounds of formulas (I)-(IV) are covalently attached to the surface of the implantable medical device, or a portion thereof, without substantially being incorporated beneath the surface.

[0104] For example, the indicator compound of Formula (I), (II), (III) or (IV) having one or more reactive groups such as an isocyanate, may be formulated into a composition and sprayed onto the surface of the implantable medical device after the device has been manufactured. The one or more reactive groups of the compound of Formula (I), (II), (III) or (IV) can react with a group such as an amino or hydroxyl group on the surface of a copolymer structure of the implantable medical device to form covalent bonds. In some embodiments, the copolymer includes a polyacrylate or poly(meth)acrylate that includes an amino or hydroxyl functional group that can react with a reactive group of the indicator compound of Formula (I), (II), (III) or (IV) to form a covalent bond.

[0105] In some embodiments, the copolymer includes polyvinyl alcohol (PVA), or copolymers derived from 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate (HEMA), 2- hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-sulfoethyl acrylate, 2-sulfoethyl methacrylate, glycidyl acrylate, glycidyl methacrylate (GMA), or copolymers having poly(ethylene glycol), PEG, terminal groups. In some embodiments, the copolymer includes amines derived from aminoethyl acrylate, aminoethyl methacrylate, and acrylonitrile monomers, following reduction of the nitrile to an amine. As such, in this embodiment, the compound of Formula (I), (II), (III) or (IV) is incorporated substantially at the surface of the implantable medical device by reacting with e.g., PVA, HEMA or PEG-derived copolymers of the device.

[0106] In further embodiments, one or more compounds of formulas (I)-(IV) are incorporated throughout the implantable medical device, or a portion thereof. For example, one or more compounds of formulas (I)-(IV) can be combined with one or more monomers and polymerized into a co-polymer that is molded or extruded into the implantable medical device, or a portion thereof. As such, the one or more compounds of formulas (I)-(IV) are covalently attached throughout the implantable medical device, or a portion thereof. For example, the indicator compound of Formula (I), (II), (III) or (IV) may be covalently attached to acrylate monomers that are copolymerized into copolymers that are used to make one or more components of the implantable medical device. As such, in this embodiment, the compound of Formula (I), (II), (III) or (IV) is incorporated both at and beneath the surface of said component of the device.

[0107] When an infection is suspected, or as a routine screen to detect microbial growth before clinical signs of infection are present, the desired imaging technology can be used to screen the implantation site for changes in the indicator signal from the one or more compounds of formulas (I)-(IV). The device allows early detection and treatment of infection. In some embodiments, the medical device delivers a therapeutic composition to the site of infection. In some embodiments, the patient is treated with antimicrobial

compositions, for example orally or intravenously.

[0108] In an embodiment, the medical device comprises a high concentration of indicator and/or reporter associated therewith, such that the intensity of the indicator or reporter signal under acidic conditions is high enough to be detectable above the background level of signal, such as that due to chromofluors naturally present in the body. In an embodiment, the signal at the medical device implantation site is determined after implantation but prior to infection. This initial signal intensity can be used as a control for background signal and compared to later signal levels to determine whether the signal has increased or changed, thus indicating the presence of infection.

Conjugation [0109] In some aspects, the indicator or reporter compounds of Formula (I), (II), (III) and (IV) can be conjugated to the surface of a medical device by covalent bonding through compatible functional groups. That is to say that the surface of the medical device contains or is modified to contain a first reactive functional group and the indicator or reporter compounds of Formula (I), (II), (III) and (IV) is modified to contain a compatible functional group. Compatible functional groups are those functionalities which are capable of reacting with the first reactive functional group to form a covalent bond. Non-limiting examples of first reactive functional groups and functional groups compatible therewith are provided in the table below, it being understood that the first reactive functional group and the compatible functional groups can be interchanged.

[0110] The reactions necessary to form such covalent bonds are well known and are described in numerous standard organic chemistry texts.

[0111] In some aspects, the indicator or reporter compounds of Formula (I), (II), (III) and (IV) can be conjugated to the surface of a medical device by covalent bonding through compatible polymerizable groups or reactive groups. In some embodiments, the indicator or reporter compounds of Formula (I), (II), (III) and (IV) is covalently bound to at least a portion of the surface of the device. In another embodiment, the indicator or reporter compounds of Formula (I), (II), (III) and (IV) is integrated at least into or on a portion of the surface layer of the device.

[0112] In some embodiments, the surface of a medical device and/or the compound of Formula (I), (II), (III) or (IV), comprise a polymerizable group or reactive group that is selected from the group consisting of -NCO, -NCS, -CO ₂ R ¹¹ , -ethynyl, -N ₃ , allyl or is wherein

R ¹⁰ is selected from the group consisting of hydrogen, Ci-C ₆ alkyl, C0 ₂ H, C0 ₂ R ¹² , CN, and CON(R ¹³ ) ₂ ; and

R ¹⁵ is selected from the group consisting of hydrogen, Ci-C ₆ alkyl optionally substituted with 1-3 hydroxy groups, and CN.

[0113] The one or more reactive groups of the compound of Formula (I), (II), (III) or (IV) can react with a group such as an amino or hydroxyl group on the surface of a copolymer structure of the implantable medical device to form covalent bonds. In some embodiments, the copolymer includes polyvinyl alcohol, PVA, or copolymers derived from 2-hydroxyethyl methacrylate, HEMA, or copolymers having poly(ethylene glycol), PEG, terminal groups or amines derived from acrylonitrile monomers, following reduction of the nitrile to an amine. As such, in this embodiment, the compound of Formula (I), (II), (III) or (IV) is incorporated substantially at the surface of the implantable medical device or a PVA, HEMA or PEG- derived component of the device. In some embodiments, the compound of Formula (I), (II), (III) or (IV) has a reactive group that reacts with the hydroxyl group of a carbohydrate based wound covering such as those using cotton or hylauronic acid.

[0114] In some embodiments, the implantable medical device has conjugated to it by covalent bonding a single indicator or reporter compound of Formula (I), (II), (III) and (IV). For example, a single pH indicator can be used which changes color in acidic pH as well as the basic pH. The color change transition can be colored to colorless or colorless to colored or one color to another color. For example, the pH indicator can have first color to second color in acidic pH and the same pH indicator can have third color to fourth color in alkaline pH. A single pH indicator that changes color in acidic pH and in alkaline pH is demonstrated by the following examples.

[0115] In some embodiments, the implantable medical device has two or more different indicators or reporter compounds of Formula (I), (II), (III) and (IV) conjugated to the medical device by covalent bonding. For example, separate pH indicators can be used which one changes color in an acidic pH and another changes color in a basic pH.

[0116] The color change transition can be colored to colorless or colorless to colored or one color to another color or a first color to a second color to a third color to a fourth color and so on, depending upon the number of pH indicators used.

[0117] The color change transitions can be in acidic pH and in alkaline pH. The color change transitions can be in acidic pH and in acidic pH. The color change transitions can be in alkaline pH and in alkaline pH. The color change transitions can be in acidic pH, in acidic pH, in alkaline pH and in alkaline pH (depending upon the number of indicators used.

Additional Indicators and Reporters

[0118] In some embodiments, the implantable medical device, which has one or more different indicators or reporter compounds of Formula (I), (II), (III) and (IV) conjugated to the medical device by covalent bonding, further comprises indicator or reporter compounds which are not compounds of Formula (I), (II), (III) and (IV).

[0119] As used herein, the term "indicator" refers to a compound or device that produces a signal in presence of microbial growth. The signal can be electromagnetic such as a change in absorption which can be observed by naked eye and/or by using an emission and/or absorption spectrophotometer. Such indicators include by way of example only, dyes including pH indicators, metals such as gadolinium, pH sensitive fluorescent indicators and the like.

[0120] In some embodiments, the implantable medical device, which has one or more different indicators or reporter compounds of Formula (I), (II), (III) and (IV) conjugated to the medical device by covalent bonding, further comprises one or more "additional indicators" described herein, which are incorporated into implantable devices but which are not compounds of Formula (I), (II), (III) and (IV). Such additional indicators include a metal selected from the group of a fluorescent moiety; a paramagnetic ion, such as gadolinium, europium, manganese, lanthanide, iron, and derivatives thereof; or a phase transition material. The indicator is capable of remote detection, for example by magnetic resonance imaging (MRI). Examples of these and other indicators are well-known in the art. For example, and without limiting the scope of the present invention, Amanlou, et al. describes several indicators that are commonly used in MRI, including small mononuclear or polynuclear paramagnetic chelates; metalloporphyrins; polymeric or macromolecular carriers (covalently or noncovalently labeled with paramagnetic chelates); particulate contrast agents (including fluorinated or non-fluorinated paramagnetic micelles or liposomes) and paramagnetic or super paramagnetic particles (e.g., iron oxides, Gd3-labeled zeolites); dimagnetic CEST polymers; dimagnetic hyperpolarization probes (gases and aerosols), and 13C-labeled compounds or ions. Amanlou, et al., Current Radiopharmaceuticals 4, 31-43 (2011). [0121] In some embodiments, the additional indicator is pH-sensitive or temperature- sensitive. In an embodiment, the indicator is a fluorescent moiety. Fluorescence is the light emitted when a molecule absorbs light at a higher energy wavelength and emits that light at a lower energy wavelength. In an embodiment, the fluorescent moiety is remotely detectable, for example by fluorescence spectroscopy.

[0122] In some embodiments, the implantable medical device, which has one or more different indicators or reporter compounds of Formula (I), (II), (III) and (IV) conjugated to the medical device by covalent bonding, further comprises an additional pH-sensitive indicators such as those described, for example, in U.S. Patent Pub. No. 2011/0104261 Al and references therein, all of which are incorporated herein by reference in their entirety. Such additional pH-sensitive indicators may include citraconyl-linked Gd chelates, Gd diethylenetriamine pentaacetic acid (DTPA) chelates, and Gd-DOTA chelates.

[0123] In some embodiments, the implantable medical device, which has one or more different indicators or reporter compounds of Formula (I), (II), (III) and (IV) conjugated to the medical device by covalent bonding, further comprises a fluorescent pH indicators that can sense pH changes within physiological ranges. See, for example,

http://www.invitrogen.corn/site/us/en/home/References/Mol ecular-Probes-The- Handbook/pH-Indicators/ Overview-of-pH-Indicators .html

[0124] In some embodiments, the implantable medical device, which has one or more different indicators or reporter compounds of Formula (I), (II), (III) and (IV) conjugated to the medical device by covalent bonding, further comprises a fluorescent moiety which is present in a liposome at self-quenching concentration. In an embodiment, a liposome comprises the fluorescent moiety and a fluorescent quencher.

[0125] Alternatively, the fluorescent moiety that is combined with the implantable device, as described herein, will be incorporated into a pH-dependent liposome and will be released from degraded liposomes in the presence of acidic pH. That is to say, that an active infection will create an acidic microenvironment which, in turn, will degrade the liposomes and/or alter the structure of the fluorescent moiety into a form that absorbs blue light. Irradiation of the skin area when the implant is made, such as an artificial knee, will indicate infection by virtue of the acidic nature of the microenvironment which can be detected non-invasively by the fluorescence emitted. [0126] The term "pH dependent liposomes," as combined with the implantable devices described herein, refers to those well-known liposomes which are stable at neutral or alkaline pH but which are unstable under acidic pH conditions. U.S. Patent Pub. No. 2011/0104261 Al, which is incorporated herein by reference in its entirety, discloses pH-sensitive liposomal probes. pH-degradable compositions, including liposomes, are disclosed in U.S. Patent Application No. 13/607431 , and PCT International Patent Application No.

PCT/US2012/054171, each of which is hereby incorporated by reference into this application in its entirety.

[0127] The term "temperature-sensitive liposomes" refers to those liposomes which are stable at normal body temperature (around 37 °C) but degrade at higher temperatures, such as those present at infection sites. Temperature-sensitive liposomes may be comprised of, for example, dipalmitoylphosphatidylcholine (DPPC) or natural or synthetic thermosensitive polymers. See, for example, Kono and Takagishi, "Temperature-Sensitive Liposomes", Methods in Enzymology 387, 73-82 (2004).

[0128] Liposomes may be comprised of any naturally-occurring or synthetic lipids and/or lipophilic compounds, including, without limitation, phosphatidylcholine, charged lipids (e.g., stearlamine), cholesterol, and/or aminoglycosides. Liposomes, including pH-sensitive liposomes, may also include lipids, lipophilic compounds, and pH-responsive copolymers as described in U.S. Patent Pub. No. 2011/0104261 Al . Liposomes that are sensitive to pH may comprise, for example, a blend of phosphatidylethanolamine (PE), or a derivative thereof, compounds containing an acidic group (e.g., carboxylic group) that acts as stabilizer at neutral pH; pH-sensitive lipids; synthetic fusogenic peptides/proteins;

dioleoylphosphatidylethanolamine; and/or attachment of pH-sensitive polymers to liposomes. Use of other compounds, for example distearoylphosphatidylcholine, hydrogenated soya PC, lipid conjugates, phosphatidylethanolamine -poly(ethylene glycol), poly[N-(2- hydroxypropyl)methacrylamide)] , poly-N-vinylpyrrolidones, L-amino-acid-based

biodegradable polymer-lipid conjugates, or polyvinyl alcohol may allow for decreased leakage of encapsulated compounds and/or longer-lasting liposomes. Similarly, coating surface with inert biocompatible polymers (such as polyethylene glycol, PEG), can increase the longevity of liposomes in vz ^' vo while also allowing such polymers to be detached by acidic pH. [0129] In some embodiments of the implantable device, nanoparticles other than lipids may be used to form a delivery vehicle analogous to a liposome. The term "liposome" is meant to encompass such analogous structures.

[0130] In some embodiments, the liposome is associated with at least one antibiotic, such as a penicillin, a cephalosporin, a carbapenem, a polymixin, a rifamycin, a lipiarmycin, a quinolone, a sulfonamide, a β-lactam, a fluoroquinolone, a glycopeptide, a ketolide, a lincosamide, a streptogramin, an aminoglycoside, a macrolide, a tetracycline, a cyclic lipopeptide, a glycylcycline, or an oxazolidinone. Antibiotics in these classes are well known in the art. One of ordinary skill in the art would understand that this list is not exhaustive and the use of any antibiotic is within the scope of this invention.

[0131] In some embodiments, an anti-infective agent (for example, an antifungal triazole or amphotericin) is associated with the liposome. These may include carbapenems, for example meropenem or imipenem, to broaden the therapeutic effectiveness.

[0132] In some embodiments, the implantable medical device, which has one or more different indicators or reporter compounds of Formula (I), (II), (III) and (IV) conjugated to the medical device by covalent bonding, further comprises reporters. The term "reporter" refers to compounds that are bound to an antibody or binding fragment thereof and which change at least one of their electromagnetic emission characters when bound to the microbe as compared to that when not bound to the microbe. For example, reporters can be fluorescent indicators which have an altered fluorescence when bound to the microbe as compared to being unbound. For example, the fluorescence signal may be quenched due to the proximity of a quenching molecule in the absence of a microbe; binding of the antibody or fragment to the microbe results in a conformational change such that the quenching molecule is no longer in close enough proximity to exert a quenching effect.

[0133] As described, in some embodiments, the implantable medical device, which has one or more different indicators or reporter compounds of Formula (I), (II), (III) and (IV) conjugated to the medical device by covalent bonding, further comprises antibodies, and fragments thereof. Antibodies, and fragments thereof, that are specific for a variety of infectious bacteria and other microbes are well-known in the art. For example, U.S. Patent No. 7,531,633 B2 discloses antibodies specific for Staphylococcus aureus. U.S. Patent Application Pub. No. 2013/0022997 discloses antibodies specific for methicillin-resistant Staphylococcus aureus (MRSA) that can distinguish MRSA from methicillin-sensitive Staphylococcus aureus (MSSA). In addition, microbe- and bacteria-specific antibodies are commercially available from a wide variety of vendors, including, for example, Kirkegaard & Perry Laboratories, Inc. and Santa Cruz Biotechnology.

[0134] Antibodies (including molecules comprising, or alternatively consisting of, antibody fragments or variants thereof) should have a binding specificity for the microbe(s) of interest such that false positives are avoided. In some embodiments, the antibody or fragment thereof binds to multiple related microbes. In preferred embodiments, the antibodies or fragments thereof specifically bind to an antigen specific for the microbe of interest and do not cross- react with any other antigens.

[0135] In an embodiment, the antibodies are human antigen-binding antibody fragments and include, but are not limited to, Fab, Fab' and F(ab')2, Fd, single-chain Fvs (scFv), single- chain antibodies, disulfide-linked Fvs (sdFv) and fragments comprising either a VL or VH domain. Antigen-binding antibody fragments, including single-chain antibodies, may comprise the variable region(s) alone or in combination with the entirety or a portion of the following: hinge region, CHI, CH2, and CH3 domains. Also included in the invention are antigen-binding fragments also comprising any combination of variable region(s) with a hinge region, CHI, CH2, and CH3 domains. The antibodies of the invention may be from any animal origin including birds and mammals. Preferably, the antibodies are human, murine (e.g., mouse and rat), donkey, ship rabbit, goat, guinea pig, camel, horse, or chicken. As used herein, "human" antibodies include antibodies having the amino acid sequence of a human immunoglobulin and include antibodies isolated from human immunoglobulin libraries or from animals transgenic for one or more human immunoglobulin and that do not express endogenous immunoglobulins, for example those described in U.S. Pat. No. 5,939,598 by Kucherlapati et al. An antibody can be humanized, chimeric, recombinant, bispecific, a heteroantibody, a derivative or variant of a polyclonal or monoclonal antibody.

[0136] In some embodiments, the antibody or binding fragment thereof has bound thereto a fluorescent moiety which changes its fluorescent character upon binding to the microbe.

[0137] In some embodiments, a plurality of different antibodies or binding fragments thereof are bound to the device each producing a unique signal for the microbe bound thereto. [0138] The term "microbe" refers to any infectious organism, including but not limited to a bacterium, fungus, yeast, or virus. Such organisms are well-known in the art. Common infectious bacteria include, but are not limited to, staphylococci, streptococci, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa. Infections are also commonly caused by Candida and mycobacteria.

Detection of Infections

[0139] Exemplary and non-limiting advantages of the implantable medical devices provided herein include the applicability to any type of implantable medical device. Further advantages include its ability to identify and report the presence of microbial infection adjacent to or on a medical device implanted in a patient. For example, the infection may be detected before the patient presents with the clinical effects of such infection.

[0140] In some embodiments, the type of infection can be indicated by the invention. For example, in one embodiment, the medical device has one or more antibodies, or binding fragments thereof, associated therewith. These antibodies are specific for a given bacteria, and when bound to that bacteria produce a unique signal evidencing the presence of the bacteria. In other embodiments, multiple different antibodies or binding fragments thereof can be used, each of which produces a unique signal for the presence of a given strain of bacteria.

UTILITY

[0141] The compounds of this invention are useful as pH indicators, particularly when polymerized, such as with another monomer such as hydroxyethyl methacrylate. The pH indicators of this invention and the polymers including the monomers of this invention are useful in contact lenses, food packaging, and bandages.

[0142] The polymerizable group is chosen relative to the polymer to be formed. For example, allyl and 2-(acryl)ethylene are readily incorporated into polyacrylates,

polymethacrylates, polymers of HEMA (2-hydroxylethylene methacrylate), polyvinylacetate, polyvinylalcohol, polystyrene, and the like. Because the pH indicators of this invention have been functionalized to include reactive functionality similar to the monomer to be

polymerized, one can form either random copolymers of the monomer and the pH indicator or block copolymers where the pH indicator is limited to a very specific part of the polymer. The latter allows only a portion of the polymer to provide pH indication.

[0143] Similarly, reactive groups such as isocyanate and thioisocyanates are readily incorporated into peptides and proteins through appropriate functional groups such as amino or hydroxyl functionalities as well as through carbohydrates via one or more of their hydroxyl functionalities. In each case, a carbohydrate based wound covering such as those using cotton, hylauronic acid, and the like can covalently couple the pH indicator directly into the carbohydrate fiber thereby avoiding leaching of the indicator. Likewise, protein based therapeutics such as those incorporating, e.g., collagen can likewise incorporate into the polymer.

[0144] The various reactive groups can also attach to nucleic acids such as DNA and R A, including siR A, providing nucleic acid probes.

[0145] In addition to the above, when multiple polymerizable groups and/or reactive groups are employed in the same molecule, the molecule can be used both as a cross-linking agent as well as a pH indicator thereby obviating the need for all or some of a separate cross-linking agent if the polymer is to be cross-linked. EXAMPLES

Example I. Synthesis of compounds of Formula (I), (II), (III) or (IV) having one or more reactive groups such as isocyanate(s) .

[0146] Reactive groups can be incorporated into compounds of Formula (I), (II), (III) or (IV) using conventional synthetic methods well known to the skilled artisan. For example, compounds of Formula (I), (II), (III) or (IV) having one or more isocyanate reactive groups can be prepared from aryl boronic acids according to conventional synthetic methods. The first step in the scheme shown below includes a cross-coupling reaction of aryl boronic acids and allylic alcohols which proceeds smoothly in toluene or dioxane in the presence of a triphenyl phosphine or triphenyl phosphite palladium catalyst. See Y. Kayaki, T. Koda, T. Ikariya, Eur. J. Org. Chem., 2004, 4989-4993.

[0147] Alternatively, a palladium-catalyzed allyl cross-coupling reaction of allylic acetates with various boronic acids gives allyl arene derivatives in good yields at room temperature in the presence of a catalytic amount of Pd(OAc) ₂ with phosphine-free hydrazone as a ligand. See T. Mino, K. Kajiwara, Y. Shirae, M. Sakamoto, T. Fujita, Synlett, 2008, 2711-2715.

[0148] Additionally, a cross-coupling reaction between aryl- and vinylboronic acids and various allylic bromides proceeds without the use of a transition-metal catalyst to give the corresponding allylated products. See M. Ueda, K. Nishimura, R. Kashima, I. Ryu, Synlett, 2012, 1085-1089

[0149] Alternatively, a room-temperature Ni-catalyzed reductive coupling of aryl bromides with secondary alkyl bromides provides products in good to excellent yields. See S. Wang, Q. Qian, H. Gong, Org. Lett., 2012, 14, 3352-3355. Example 2. Covalent linking of compounds of Formula (I), (II), (III) or (IV), having one or more reactive groups, to an implantable medical device.

[0150] Compounds of Formula (I), (II), (III) or (IV), having one or more reactive groups, such as isocyanate groups, can be formulated as a solution e.g., in water and/or ethanol, and sprayed onto the surface of an implantable medical device where the device includes polymer components and the polymer includes one or more reactive hydroxyl, thiol or amino groups. Shown below is the formation of a carbamate bond upon contact of the reactive isocyanate group from a compound of Formula (I), (II), (III) or (IV) with a hydroxyl group from a HEMA polymer portion of the implantable medical device after the compound of Formula (I), (II), (III) or (IV) is sprayed onto the device.

Implantable Device