Microbubble complexes and methods of use

Abstract

The present invention relates to a microbubble complex comprising a microbubble having an outer shell comprising a mixture of native and denatured albumin encapsulating a perfluorocarbon gas, a therapeutic agent, a bifunctional linker having one end attached to the therapeutic agent and the other attached to a ligand and wherein the ligand is bound to the other shell of the microbubble through hydrophobic interactions. Also included are methods for delivering the aforementioned microbubble complex to a tissue target.

1 . A microbubble complex comprising:
 a microbubble having an outer shell comprising a mixture of native and denatured albumin and a hollow core encapsulating a perfluorocarbon gas;   a therapeutic agent selected from a group comprising a small molecule chemotherapeutic agent, peptide, carbohydrate, oligonucleotide, cytotoxin, protein synthesis inhibitor, or combination thereof;   a bifunctional linker having one end attached to the therapeutic agent and the other attached to a ligand through reaction of a reactive group on said ligand; and   wherein the ligand is bound to the outer shell of the microbubble through hydrophobic interactions.   
     
     
         2 . The complex of  claim 1  wherein the therapeutic agent is an oligonucleotide. 
     
     
         3 . The complex of  claim 2  wherein the oligonucleotide is a naturally occurring or modified DNA or RNA. 
     
     
         4 . The complex of  claim 3  wherein the RNA is a small interfering RNA. 
     
     
         5 . The complex of  claim 1  wherein the bifunctional linker comprises a oligo- or poly-amino acid, peptide, saccharide, nucleotide, organic moiety having approximately 1 to 250 carbon atoms, or a combination thereof. 
     
     
         6 . The complex of  claim 1  wherein the bifunctional linker comprises tetraethylene glycol (TEG) or polyethylene glycol. 
     
     
         7 . The complex of  claim 1  wherein the reactive group comprises an activated ester, phosphoramidite, isocyanate, isothiocyanate, aldehyde, acid chloride, sulfonyl chloride, maleimide, alkyl halide, amine, phosphine, phosphate, alcohol or thiol. 
     
     
         8 . The complex of  claim 7  wherein the reactive group is an amine. 
     
     
         9 . The complex of  claim 1  wherein the ligand is a fatty acid, steroid, or a combination thereof. 
     
     
         10 . The complex of  claim 9  wherein the fatty acid is myristoyl, lithocolic-oleyl, docosanyl, lauroyl, steoroyl, palmitoyl, oleoyl, linoleoyl, or a combination thereof. 
     
     
         11 . The complex of  claim 9  wherein the steroid is cholesterol, cholic acid, lithocholic acid, chenodeoxycholic acid or a combination thereof. 
     
     
         12 . The complex of  claim 1  wherein the ligand is 4-iodophenyl butyric acid or an analog or derivative thereof. 
     
     
         13 . The complex of  claim 1  wherein the amount of denature to native albumin is in the range of approximately 0.5 to 30 wt %. 
     
     
         14 . The complex of  claim 13  wherein the range of denature to native albumin is approximately 1 to 15 wt %. 
     
     
         15 . The complex of  claim 1  wherein the therapeutic agent comprises siRNA, the linker comprises tetraethylene glycol, and the ligand comprises cholesterol. 
     
     
         16 . A method for delivering a microbubble complex to a tissue target comprising the steps of:
 providing a microbubble complex, said complex comprising;
 a microbubble having an outer shell comprising a mixture of native and denatured albumin and a hollow core encapsulating a perfluorocarbon gas; 
 a therapeutic agent selected from a group comprising a small molecule chemotherapeutic agent, peptide, carbohydrate, oligonucleotide, cytotoxin, protein synthesis inhibitor, or combination thereof; 
 a bifunctional linker having one end attached to the therapeutic agent and the other attached to a ligand through reaction of a reactive group on said ligand; and 
 wherein the ligand is bound to the outer shell of the microbubble through hydrophobic interactions; 
   administrating the microbubble complex to a subject wherein the subject is the source of the tissue target; and   administering ultrasonic energy to the subject, wherein said energy is sufficient to cause cavitation of the microbubble complex in the tissue target.   
     
     
         17 . The method of  claim 16  wherein the tissue target is in vivo and administrating the microbubble complex comprises intravenous or intraperitoneal injection of the microbubble complex. 
     
     
         18 . The method of  claim 16  further comprising the step of visualizing the microbubble complex at the tissue target prior to administering the ultrasonic energy for cavitation of the microbubble complex. 
     
     
         19 . The method of  claim 16  wherein the visualizing and administering the ultrasonic energy are performed in real time. 
     
     
         20 . The method of  claim 16  wherein the tissue target is in vitro. 
     
     
         21 . The method of  claim 16  wherein the therapeutic agent is an oligonucleotide. 
     
     
         22 . The method of  claim 21  wherein the oligonucleotide is a naturally occurring or modified DNA or RNA. 
     
     
         23 . The method of  claim 22  wherein the RNA is a small interfering RNA. 
     
     
         24 . The method of  claim 16  wherein the bifunctional linker comprises a oligo- or poly-amino acid, peptide, saccharide, nucleotide, organic moiety having approximately 1 to 250 carbon atoms, or a combination thereof. 
     
     
         25 . The method of  claim 16  wherein the bifunctional linker comprises tetraethylene glycol (TEG) or polyethylene glycol. 
     
     
         26 . The method of  claim 16  wherein the reactive group comprises an activated ester, phosphoramidite, isocyanate, isothiocyanate, aldehyde, acid chloride, sulfonyl chloride, maleimide, alkyl halide, amine, phosphine, phosphate, a alcohol or thiol. 
     
     
         27 . The method of  claim 26  wherein the reactive group is an amine. 
     
     
         28 . The method of  claim 16  wherein the ligand is a fatty acid, steroid, or a combination thereof. 
     
     
         29 . The method of  claim 28  wherein the fatty acid is myristoyl, lithocolic-oleyl, docosanyl, lauroyl, steoroyl, palmitoyl, oleoyl, linoleoyl, or a combination thereof. 
     
     
         30 . The method of  claim 28  wherein the steroid is cholesterol, cholic acid, lithocholic acid, chenodeoxycholic acid or a combination thereof. 
     
     
         31 . The method of  claim 16  wherein the ligand is 4-iodophenyl butyric acid or an analog or derivative thereof. 
     
     
         32 . The method of  claim 16  wherein the amount of denature to native albumin is in the range of approximately 0.5 to 30 wt %. 
     
     
         33 . The method of  claim 32  wherein the range of denature to native albumin is approximately 1 to 15 wt %. 
     
     
         34 . The method of  claim 16  wherein the therapeutic agent comprises siRNA, the linker comprises tetraethylene glycol, and the ligand comprises cholesterol.