Biodegradable polymer microsphere compositions for parenteral administration

1. A composition for parenteral administration comprising:

a plurality of microspheres,

wherein each microsphere comprises a polymer matrix and an active therapeutic agent,

wherein the polymer matrix comprises a homogenous mixture of a biodegradable polymer and a cellulose-derived material selected from the group consisting of cellulose ethers and cellulose esters,

wherein the biodegradable polymer has a molecular weight of greater than 10,000 Daltons,

wherein the percentage of active therapeutic agent is from about 10% to about 40% w/w of each microsphere,

wherein the biodegradable polymer comprises a polyester polymer comprising a co-block polymer selected from the group consisting of poly(D,L-lactide-co-glycolide) and poly(L-lactide-co-glycolide),

wherein the percentage of biodegradable polymer is from about 50% to about 95% w/w of each microsphere,

wherein the cellulose-derived material comprises ethyl cellulose,

wherein the percentage of cellulose-derived material is from about 0.5% to about 6% w/w of each microsphere, and

wherein the cellulose-derived material (CDM) comprises a viscosity fraction of about 0.1% to about 5%.

2. The composition of claim 1 , wherein the biodegradable polymer is selected from the group consisting of a bulk-eroding polymer, a surface-eroding polymer, and a polyanhydride polymer.

3. The composition of claim 1 , wherein the co-block polymer is poly(D,L-lactide-co-glycolide) and wherein the percentage of lactide is from about 50% to about 80% w/w of the co-block polymer and wherein the percentage of glycolide is from about 20% to about 50% w/w of the co-block polymer.

4. The composition of claim 1 , wherein the co-block polymer is poly(L-lactide-co-glycolide) and wherein the percentage of lactide is from about 50% to about 80% w/w of the co-block polymer and wherein the percentage of glycolide is from about 20% to about 50% w/w of the co-block polymer.

5. The composition of claim 1 , wherein the cellulose-derived material further comprises one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, and sodium carboxymethyl cellulose.

6. The composition of claim 1 , wherein the active therapeutic agent is selected from the group consisting of an integrase inhibitor, an antiparasitic, a steroid hormone, and a somatostatin analogue.

7. The composition of claim 1 , wherein the active therapeutic agent is an organic compound having a molecular weight of less than 1000 daltons.

8. The composition of claim 1 , further comprising a pharmaceutically acceptable carrier, excipient or diluent.

9. The composition of claim 1 , wherein the composition comprises at least one member selected from the group consisting of an aqueous solution and a buffer solution.

10. The composition of claim 9 , further comprising a pharmaceutical surfactant.

11. The composition of claim 9 , further comprising a cryoprotectant.

12. A method for treating a subject having a disease or condition indicating a need for treatment comprising parenteral administration, the method comprising administering a composition of claim 1 to the subject parenterally.

13. The composition of claim 1 , wherein at least 90% of the plurality of microspheres have a particle diameter from about 40 μm to about 70 μm.

14. The composition of claim 1 , wherein at least 90% of the plurality of microspheres have a particle diameter from about 50 μm to about 60 μm.

15. The composition of claim 1 , wherein at least 50% of the active therapeutic agent is released from the microspheres over a period of at least 50 days.

16. The composition of claim 1 , wherein the active therapeutic agent is released from the microspheres over a period of from 100 to about 120 days.