Synthesis and composition of amino acid linking groups conjugated to compounds used for the targeted imaging of tumors

Abstract

The present disclosure relates to compounds that are useful as near-infrared fluorescence probes, wherein the compounds include i) a pteroyl ligand that binds to a target receptor protein, ii) a dye molecule, and iii) a linker molecule that comprises an amino acid or derivative thereof. The disclosure further describes methods and compositions for incorporating the compounds as used for the targeted imaging of tumors. Conjugation of the amino acid linking groups increase specificity and detection of the compound. Methods and compositions for use thereof in diagnostic imaging are contemplated.

1 . A method of imaging a head and neck cancer in a subject in need thereof comprising
 administering to the subject an effective amount of a compound capable of binding to a folate receptor expressed in a head and neck cancerous cell, the compound having the formula:   
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt or isotope thereof, wherein: X is a single amino acid or a single amino acid derivative thereof, wherein the single amino acid or single amino acid derivative contains an —OH, —NH 2 , or —SH functional group, and Y is a dye that has a fluorescence excitation and emission spectra in the near infra-red range, wherein Y is represented by the formula: 
       
         
           
           
               
               
           
         
         wherein, R 1  is independently selected from the group consisting of O, S, N and C, and R 2  is independently selected from the group consisting of CH 2  and CH 2 CH 2 , and the compound enhances the fluorescence of the dye, Y; and 
         fluorescent imaging of an area in the subject's body where the compound binds to at least one head and neck cancerous cell. 
       
     
     
         2 . The method of  claim 1 , wherein the head and neck cancer is pharynx cancer, laryngeal cancer, hypopharyngeal cancer, oral cavity cancer, oropharyngeal cancer, nasopharyngeal cancer, nasal cavity cancer, paranasal sinus cancer, salivary gland cancer. 
     
     
         3 . A method of in vivo identification of cancerous tissue in a subject with head and neck cancer, comprising
 administering a compound to the subject, wherein the compound has the formula:   
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt or isotope thereof, wherein: X is a single amino acid or a single amino acid derivative thereof, wherein the single amino acid or single amino acid derivative contains an —OH, —NH 2 , or —SH functional group, and Y is a dye that has a fluorescence excitation and emission spectra in the near infra-red range, wherein Y is represented by the formula: 
       
         
           
           
               
               
           
         
         wherein, R 1  is independently selected from the group consisting of O, S, N and C, and R 2  is independently selected from the group consisting of CH 2  and CH 2 CH 2 , and the compound enhances the fluorescence of the dye, Y; 
         irradiating an area of subject's body containing cancerous tissue with at least one excitation wavelength in the near infrared range; 
         fluorescent imaging the compound in the area of the subject's body wherein the compound has bound to or been taken up by the cancerous tissue in the subject's body, in response to the at least one excitation wavelength, and 
         determining the location or surface area of the cancerous tissue in the subject. 
       
     
     
         4 . The method of  claim 1 , wherein the head and neck cancer is pharynx cancer, laryngeal cancer, hypopharyngeal cancer, oral cavity cancer, oropharyngeal cancer, nasopharyngeal cancer, nasal cavity cancer, paranasal sinus cancer, salivary gland cancer. 
     
     
         5 . The method of  claim 3 , further comprising the step of using an endoscopic device to deliver the excitation light to the site, to receive fluorescence emanating from the site within a body cavity, and to aid in formation of a direct image of the fluorescence from the diseased tissue. 
     
     
         6 . A method for diagnosing head and neck cancer during surgery in a subject in need thereof, comprising:
 administering to the subject a composition comprising a compound wherein the compound having the formula:   
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt or isotope thereof, wherein: X is a single amino acid or a single amino acid derivative thereof, wherein the single amino acid or single amino acid derivative contains an —OH, —NH 2 , or —SH functional group, and Y is a dye that has a fluorescence excitation and emission spectra in the near infra-red range, wherein Y is represented by the formula: 
       
         
           
           
               
               
           
         
         wherein, R 1  is independently selected from the group consisting of O, S, N and C, and R 2  is independently selected from the group consisting of CH 2  and CH 2 CH 2 , and the compound enhances the fluorescence of the dye, Y; 
         irradiating an area of the subject's body containing cancerous tissue with a light having at least one excitation wavelength in the range from about 600 nm to about 850 nm; 
         fluorescence imaging the compound in the area of the subject's body wherein the compound has bound to or been taken up by the diseased tissue in the body part, wherein the targeting construct fluoresces in response to the at least one excitation wavelength; 
         determining the location or surface area of the cancerous tissue in the subject; and 
         removing at least a portion of the cancerous tissue. 
       
     
     
         7 . The method of  claim 6 , wherein the head and neck cancer is pharynx cancer, laryngeal cancer, hypopharyngeal cancer, oral cavity cancer, oropharyngeal cancer, nasopharyngeal cancer, nasal cavity cancer, paranasal sinus cancer, salivary gland cancer. 
     
     
         8 . A method for in vivo diagnosis of tumor tissue in a subject with head and neck cancer comprising:
 administering a diagnostically effective amount of at least one biologically compatible fluorescing targeting construct comprising a compound that can be bound to or be taken up by tumor tissue and a fluorophore responsive to at least one wavelength of light in the range from about 600 nm to about 850 nm, wherein the compound has the formula:   
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt or isotope thereof, wherein: X is a single amino acid or a single amino acid derivative thereof, wherein the single amino acid or single amino acid derivative contains an —OH, —NH 2 , or —SH functional group, and Y is a dye that has a fluorescence excitation and emission spectra in the near infra-red range, wherein Y is represented by the formula: 
       
         
           
           
               
               
           
         
         wherein, R 1  is independently selected from the group consisting of O, S, N and C, and R 2  is independently selected from the group consisting of CH 2  and CH 2 CH 2 , and the compound enhances the fluorescence of the dye, Y; and 
         determining the location or surface area of the tumor tissue in the subject's body by directly viewing fluorescence emanating from the targeting construct bound or taken up in the tumor tissue upon irradiation thereof with a light providing the at least one excitation wavelength for in the range from about 600 nm to about 850 nm the fluorescent targeting construct. 
       
     
     
         9 . The method of  claim 8 , wherein the head and neck cancer is pharynx cancer, laryngeal cancer, hypopharyngeal cancer, oral cavity cancer, oropharyngeal cancer, nasopharyngeal cancer, nasal cavity cancer, paranasal sinus cancer, salivary gland cancer.