Biodegradable polyphosphates complex for controlled release of bioactive substances and related methods

Abstract

The present invention is directed to a biodegradable system for the controlled release of bioactive substances. This system comprises novel biodegradable and biocompatible polyphosphoesters that carry positive charges. Process for making these polyphosphoesters, compositions containing these polyphosphoesters and biologically active substances, articles and methods for delivery of drugs and genes using this system are described. A controlled gene delivery system based on these polyphosphoesters is prepared by complex coacervation of nucleic acid (DNA or RNA) with polymers. The release rates can be manipulated by adjusting the charge ratios of polyphosphoesters to nucleic acids. This gene delivery system yields a higher gene expression in muscle when injected intramuscularly.

1 . A biodegradable polymer composition formed by complexation in aqueous solution comprising:
 (a) At least one negatively charged molecule selected from the group consisting of DNA, RNA, proteins, and polysaccharides; and   (b) A water soluble and positively chargeable biodegradable polymer that is capable of forming a complex with the at least one negatively charged molecule and comprising the recurring monomeric unit shown in Formula I:   
       
         
           
           
               
               
           
         
         wherein 
         R 1  is a divalent aliphatic organic moiety; 
         R 2  is a positively charged alkyl or heteroalicyclic group selected from the groups consisting of primary amine, secondary amine, tertiary amine, and quaternary amine; 
         m is an integer from 1 to 6; 
         n is from 20 to 2,000. 
       
     
     
         2 . The biodegradable polymer composition of  claim 1 , wherein the at least one negatively charged molecule accounts for 20-60% by weight of the total weight of the composition. 
     
     
         3 . The biodegradable polymer composition of  claim 1 , wherein the polymer is in aqueous solution in concentrations ranging from about 1 μg/ml to about 500 μg/ml. 
     
     
         4 . The biodegradable polymer composition of  claim 1 , wherein the polymer has between about 30 and about 200 phosphate groups in the polymer backbone. 
     
     
         5 . The biodegradable polymer composition of  claim 1 , wherein R 1  is defined in Formula II 
       
         
           
           
               
               
           
         
         wherein each occurrence of R 3  and R 4  are independently selected from the group consisting of hydrogen or alkyl group; and 
         q is 2 to 4. 
       
     
     
         6 . A method comprising:
 causing a positively charged biodegradable polymer of Formula I   
       
         
           
           
               
               
           
         
         to complex the at least one negatively charged molecule; 
         wherein: 
         R 1  is a divalent aliphatic organic moiety; 
         R 2  is a positively charged alkyl or heteroalicyclic group selected from the groups consisting of primary amine, secondary amine, tertiary amine, and quaternary amine; 
         m is an integer from 1 to 6; and 
         n is from 20 to 2,000. 
       
     
     
         7 . The method of  claim 6 , wherein R 1  is defined in Formula II 
       
         
           
           
               
               
           
         
         wherein each occurrence of R 3  and R 4  are independently selected from the group consisting of hydrogen or alkyl group; and 
         q is 2 to 4. 
       
     
     
         8 . The method of  claim 6 , wherein the polymer has between about 30 and about 200 phosphate groups in the polymer backbone. 
     
     
         9 . The method of  claim 6 , wherein the polymer is in aqueous solution in concentrations ranging from about 1 μg/ml to about 500 μg/ml. 
     
     
         10 . The method of  claim 6 , wherein the at least one negatively charged molecule is DNA. 
     
     
         11 . The method of  claim 6 , wherein the at least one negatively charged molecule is RNA. 
     
     
         12 . The method of  claim 6 , wherein the at least one negatively charged molecule is a protein or polypeptide. 
     
     
         13 . The method of  claim 6 , wherein the at least one negatively charged molecule is a polysaccharide. 
     
     
         14 . The method of  claim 6 , wherein the polymer is capable of complexing 20-60% by weight of the at least one negatively charged molecule. 
     
     
         15 . The method of  claim 10 , wherein the polymer is capable of complexing 20-60% by weight of the at least one negatively charged molecule. 
     
     
         16 . The method of  claim 11 , wherein the polymer is capable of complexing 20-60% by weight of the at least one negatively charged molecule. 
     
     
         17 . The method of  claim 12 , wherein the polymer is capable of complexing 20-60% by weight of the at least one negatively charged molecule. 
     
     
         18 . The method of  claim 13 , wherein the polymer is capable of complexing 20-60% by weight of the at least one negatively charged molecule.