Methods for the delivery of bioactive substances with biodegradable polyphosphates

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 method comprising:
 (a) providing a biodegradable polymer composition formed by complexation in aqueous solution comprising:
 at least one negatively charged bioactive molecule; and 
 a water soluble and positively charged 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; and 
         
         (b) administering the composition to an organism under conditions conducive to the delivery of at least a portion of the composition. 
       
     
     
         2 . The method of  claim 1 , wherein the bioactive molecule is delivered to a biological fluid, cell, or tissue. 
     
     
         3 . The method of  claim 2 , wherein the bioactive molecule is released in a controlled manner when contacted with the biological fluid, cell, or tissue. 
     
     
         4 . The method of  claim 1 , wherein the bioactive molecule is released from the composition extracellularly. 
     
     
         5 . The method of  claim 1 , wherein the bioactive molecule is released from the composition intracellularly. 
     
     
         6 . The method of  claim 1 , wherein the bioactive molecule comprises about 20% to about 60% by weight of the composition. 
     
     
         7 . The method of  claim 1 , wherein the biodegradable polymer has between about 20 and about 200 phosphate groups. 
     
     
         8 . The method of  claim 1 , wherein the bioactive molecule is at least one of DNA, RNA, protein, polypeptides, hormones, and polysaccharides. 
     
     
         9 . The method of  claim 1 , wherein the bioactive molecule is a growth factor. 
     
     
         10 . The method of  claim 1 , wherein the bioactive molecule is a nucleic acid. 
     
     
         11 . The method of  claim 10 , wherein the nucleic acid selected from the group consisting of DNA sequences; genes; gene fragments; DNA encoding: vaccines, therapeutic agents, cytokines, immunoadjuvants, and cancer therapeutic agents; RNA; and combinations thereof. 
     
     
         12 . The method of  claim 1 , wherein the bioactive molecule comprises a polypeptide. 
     
     
         13 . The method of  claim 10 , wherein the nucleic acid comprises DNA encoding an antigen, DNA encoding a cytokine, or a combination of DNA encoding an antigen and DNA encoding a cytokine. 
     
     
         14 . The method of  claim 1 , wherein the bioactive molecule is an antisense nucleotide sequence to an organism. 
     
     
         15 . The method of any one of  claims 1 , wherein the positively charged biodegradable polymer composition is delivered in vivo. 
     
     
         16 . The method of  claim 1 , wherein the bioactive molecule is a protein vaccine or a DNA vaccine. 
     
     
         17 . The method of  claim 15 , wherein the positively charged biodegradable polymer composition is delivered intramuscularly.