Compositions comprising biodegradable copolymers for prolonged local release of an antibiotic

1. A parenteral pharmaceutical composition comprising a biodegradable poly(ester-anhydride) copolymer of ricinoleic acid (RA) and sebacic acid (SA) having alternating or semi-alternating ester and anhydride bonds and an antibiotic, the composition being a sustained release depot system which releases a local therapeutically effective amount of the antibiotic over a period of about 1 day to about 20 weeks, wherein 24 hours after a single parenteral administration and throughout said period, the systemic level of the antibiotic or a metabolite thereof is about 10 μg/ml or less.

2. The pharmaceutical composition of claim 1 , which releases a local therapeutically effective amount of the antibiotic over a period of about 1 week to about 8 weeks.

3. The pharmaceutical composition of claim 1 , wherein 24 hours after a single parenteral administration and throughout said period, the systemic level of the antibiotic or a metabolite thereof is about 5 μg/ml or less.

4. The pharmaceutical composition of claim 3 , wherein 24 hours after a single parenteral administration and throughout said period, the systemic level of the antibiotic or a metabolite thereof is about 1 μg/ml or less.

5. The pharmaceutical composition of claim 1 , wherein the parenteral administration comprises subcutaneous injection.

6. The pharmaceutical composition of claim 1 , wherein the parenteral administration comprises intramuscular injection.

7. The pharmaceutical composition of claim 1 , wherein the parenteral administration comprises intraosseous injection.

8. The pharmaceutical composition of claim 1 , wherein the parenteral administration comprises periosteal injection.

9. The pharmaceutical composition of claim 1 , wherein the copolymer has a monomer ratio of ricinoleic acid to sebacic acid in the range of from about 60:40 to about 80:20 (w/w).

10. The pharmaceutical composition of claim 1 , wherein the copolymer has an average molecular weight of from about 2,000 to about 50,000 daltons.

11. The pharmaceutical composition of claim 1 , wherein the copolymer in the composition is degraded in vivo at a slower rate than the local or systemic release rate of the antibiotic.

12. The pharmaceutical composition of claim 1 , wherein the antibiotic is an aminoglycoside.

13. The pharmaceutical composition of claim 12 , wherein the aminoglycoside is gentamicin or a pharmaceutically acceptable salt thereof.

14. The pharmaceutical composition of claim 1 , comprising a concentration of the antibiotic of between about 1% and about 50% (w/w).

15. The pharmaceutical composition of claim 14 , comprising a concentration of the antibiotic of between about 5% and about 30% (w/w).

16. The pharmaceutical composition of claim 15 , comprising a concentration of the antibiotic of about 10% (w/w) or about 20% (w/w).

17. The pharmaceutical composition of claim 1 , providing reduced incidence of adverse events or reduced severity of adverse events of the antibiotic at the local or systemic level, wherein the adverse events are selected from toxicity, decrease in gut microbiota, and development of antibiotic resistance.

18. A parenteral pharmaceutical composition comprising a biodegradable poly(ester-anhydride) copolymer of ricinoleic acid (RA) and sebacic acid (SA) having alternating or semi-alternating ester and anhydride bonds and a therapeutically effective amount of gentamicin or a pharmaceutically acceptable salt thereof, the composition provides an in-vitro release of not more than about 20% of gentamicin in 25 days in 1 ml of 0.1M phosphate buffer at pH 7.4, 100 rpm and 37° C.

19. The pharmaceutical composition of claim 18 , wherein the copolymer has a monomer ratio of ricinoleic acid to sebacic acid in the range of from about 60:40 to about 80:20 (w/w).

20. The pharmaceutical composition of claim 18 wherein the copolymer has an average molecular weight of from about 2,000 to about 50,000 daltons.

21. The pharmaceutical composition of claim 18 , comprising a concentration of the gentamicin or a pharmaceutically acceptable salt thereof of about 10% (w/w).