Biodegradable poly(beta-amino esters) and uses thereof

A composition for delivering an agent to a patient, tissue, organ, or cell comprising an agent and a polymer of the formula:

• wherein:
• linker A is selected from the group consisting of heteroatom-containing carbon chains of 1 to 30 atoms, and carbon chains and heteroatom-containing carbon chains with at least one substituent selected from the group consisting of branched and unbranched alkyl, branched and unbranched alkenyl, branched and unbranched alkynyl, amino, alkylamino, dialkylamino, trialkylamino, aryl, ureido, heterocyclic, aromatic heterocyclic, cyclic, aromatic cyclic, halogen, hydroxyl, alkoxy, cyano, amido, carbamoyl, carboxyl, acyloxy, acyl, carbonyldioxyl, alkylthioether, and thiol groups;
• linker B is selected from the group consisting of heteroatom-containing carbon chains of 1 to 30 atoms, and carbon chains and heteroatom-containing carbon chains with at least one substituent selected from the group consisting of branched and unbranched alkyl, branched and unbranched alkenyl, branched and unbranched alkynyl, amino, alkylamino, dialkylamino, trialkylamino, ureido, halogen, hydroxyl, alkoxy, cyano, amido, carbamoyl, carboxyl, acyloxy, acyl, carbonyldioxyl, alkylthioether, and thiol groups;
• R1 and R2 are each independently selected from the group consisting of branched and unbranched alkyl, branched and unbranched alkenyl, branched and unbranched alkynyl, aryl, heterocyclic, and aromatic heterocyclic, each of which may be substituted with at least one substituent selected from the group consisting of dialkylamino, trialkylamino, aryl, heterocyclic, aromatic heterocyclic, halogen, hydroxyl, alkoxy, alkylthioether, and thiol;
• R3, R4, R5, R6, R7, and R8 are each hydrogen;
• R9, R10, or both R9 and R10 are each independently selected from the group consisting of hydrogen, branched and unbranched alkyl, branched and unbranched alkenyl, branched and unbranched alkynyl, aryl, halogen, hydroxyl, alkoxy, carbamoyl, acyloxy, carbonyldioxyl, amido, thiohydroxyl, alkylthioether, amino, alkylamino, dialkylamino, trialkylamino, cyano, ureido, substituted alkanoyl, cyclic, cyclic aromatic, heterocyclic, and aromatic heterocyclic groups, each of which may be substituted with at least one substituent selected from the group consisting of branched and unbranched alkyl, branched and unbranched alkenyl, branched and unbranched alkynyl, amino, alkylamino, dialkylamino, trialkylamino, aryl, ureido, heterocyclic, aromatic heterocyclic, cyclic, aromatic cyclic, halogen, hydroxyl, alkoxy, cyano, amido, carbamoyl, carboxyl, acyloxy, acyl, carbonyldioxyl, alkylthioether, and thiol groups;
• the counter anion is selected from the group consisting of chloride, fluoride, bromide, iodide, sulfate, nitrate, fumarate, acetate, carbonate, stearate, laurate, and oleate;
• and
• n is an integer between 5 and 10,000;
• wherein the agent and the polymer are not covalently attached.