Multifunctional self-assembling polymeric nanosystems

1. A method of making a combinatorial formulation library comprising a plurality of therapeutic agent-loaded polymeric nanoparticulate delivery systems, the method comprising:

a) determining the partition coefficient of a therapeutic agent, wherein the therapeutic agent is selected from an siRNA and an anticancer drug;

wherein the anticancer drug is selected from the group consisting of tamoxifen, paclitaxel, doxorubicin, camptothecin, topotecan, irinotecan, KRN 5500 (KRN), dexamethasone, methylprednisone, prednisone, prednisolone, ellipticin;

b) solubilizing the therapeutic agent in an aqueous solution;

c) combinatorially combining the solubilized therapeutic agent with each of a first plurality of derivatized water-soluble polymers encapsulating the therapeutic agent to form a plurality of nanoparticle cores by self-assembly;

d) combinatorially combining each of the plurality of nanoparticle cores with each of a second plurality of derivatized water-soluble polymers to form a plurality of hydrogel-encapsulated nanoparticles by self-assembly;

wherein if the therapeutic agent is an siRNA, each of the first plurality of derivatized water-soluble polymers is selected from thiolated dextran derivatives and each of the second plurality of derivatized water-soluble polymers is selected from lipid-modified dextran derivatives;

wherein if the therapeutic agent is an anticancer drug, each of the first plurality of derivatized water-soluble polymers is selected from lipid-modified dextran derivatives and each of the second plurality of derivatized water-soluble polymers is selected from thiolated dextran derivatives; and

wherein if the partition coefficient is less than 100, then the lipid-modified dextrans are derived from a fatty acid selected from the group consisting of a C 2 -C 14 ;

wherein if the partition coefficient is greater than 100, then the lipid-modified dextrans are derived from a fatty acid selected from the group consisting of a C 14 -C 28 ;

e) combinatorially combining each of the plurality of hydrogel-encapsulated nanoparticles with a plurality of activated PEG derivatives to form a plurality of therapeutic agent-loaded polymeric nanoparticulate delivery systems;

wherein each of the therapeutic agent-loaded polymeric nanoparticulate delivery systems differs from one another by at least one of:

(i) the weight ratio of therapeutic agent to first derivatized water-solubilized polymer to second derivatized water-soluble polymer to activated PEG derivative;

(ii) the identity of at least one of:

(1) the first derivatized water-solubilized polymer;

(2) the second derivatized water-soluble polymer; and

(3) the activated PEG derivative;

thereby making a combinatorial formulation library comprising a plurality of therapeutic agent-loaded polymeric nanoparticulate delivery systems.

2. The method of claim 1 , wherein at least a portion of the activated PEG derivatives are modified with thiol groups.

3. The method of claim 1 , wherein the therapeutic agent is doxorubicin.

4. The method of claim 1 , wherein the library comprises about 2 to about 5,000 different types of nanoparticles.

5. The method of claim 1 , wherein the therapeutic agent is an siRNA.

6. The method of claim 1 , wherein the therapeutic agent has a partition coefficient less than about 100.

7. The method of claim 1 , wherein the therapeutic agent is an anticancer agent selected from the group consisting of doxorubicin, tamoxifen and paclitaxel.

8. The method of claim 1 , wherein the therapeutic agent has a partition coefficient greater than about 100.

9. The method of claim 1 , wherein the thiolated dextran derivative is derivatized with a functional group selected from the group consisting of cystamine, 2-immunothiolane, cystamine hydrochloride and 2,2′-dithiopyridine.

10. The method of claim 1 , wherein the lipid-modified dextran derivative is derivatized with a functional group selected from the group consisting of stearylamine, butylamine, hexylamine, oleylamine, laurylamine, and dodecylamine.

11. The method of claim 9 , wherein the thiolated dextran derivative is derivatized with a cystamine functional group.

12. The method of claim 10 , wherein the lipid-modified dextran derivative is derivatized with a stearylamine functional group.

13. The method of claim 1 , wherein the derivatized water-soluble polymers are cross-linked.

14. The method of claim 1 , wherein the mean particle size of the therapeutic agent-loaded polymeric nanoparticulate delivery systems is between about 18.4 and about 430.4 nm.

15. The method of claim 5 , wherein the siRNA is selected from the group consisting of EGFP, ABCB1, and MDR1 siRNA.