Diketopiperazine microparticles with defined specific surface areas

1. A method of delivering an active agent to a patient in need thereof comprising administering a dry powder comprising microparticles of a diketopiperazine, the microparticles having a specific surface area of about 40 m 2 /g to 67 m 2 /g, the microparticles having been loaded with a drug or active agent, by inhalation of said dry powder by said patient.

2. The method of claim 1 , wherein the active agent is an endocrine hormone selected from the group consisting of insulin, parathyroid hormone, calcitonin, glucagon, glucagon-like peptide-1, oxyntomodulin, and an analog or active fragment of said endocrine hormone.

3. The method of claim 1 , wherein the patient has been diagnosed with diabetes.

4. The method of claim 1 , wherein said diketopiperazine is 2,5-diketo-3,6-bis(N-fumaryl-4-amino-butyl)piperazine.

5. An inhalation system comprising a breath powered inhaler and a dry powder comprising microparticles of a diketopiperazine, the microparticles having a specific surface area of about 40 m 2 /g to 67 m 2 /g.

6. The inhalation system of claim 5 , wherein said diketopiperazine is 2,5-diketo-3,6-bis(N-fumaryl-4-amino-butyl)piperazine.

7. The inhalation system of claim 5 wherein said dry powder is provided in a unit dose cartridge.

8. The inhalation system of claim 5 wherein said dry powder is provided prefilled in the inhaler.

9. The inhalation system of claim 5 wherein said inhaler has a resistance to flow of about 0.065 (√kPa)/liter per minute to 0.200 (√kPa)/liter per minute.

10. The inhalation system of claim 5 wherein said inhaler has a flow path passing through an area of powder containment and a flow path bypassing said area of powder containment, wherein in use 10-70% of the total flow existing the inhaler passes through said area of powder containment and 90-30% of the total flow existing the inhaler bypasses said area of powder containment.

11. The inhalation system of claim 10 , said inhaler having a mouthpiece, wherein said flow through the powder containment area and said flow bypassing the powder containment area combine prior to exiting the mouthpiece.

12. The inhalation system of claim 5 comprising 1 to 30 mg of said dry powder.

13. The inhalation system of claim 12 , wherein greater than 75% of the powder is dispensed when the flow rate through the inhaler is from 7 to 70 liters per minute.

14. The inhalation system of claim 13 wherein greater than 85% of the powder is dispensed.

15. The inhalation system of claim 5 wherein respirable fraction/fill is greater than 40%.

16. The inhalation system of claim 15 wherein respirable fraction/fill is greater than 50%.

17. The inhalation system of claim 15 wherein respirable fraction/fill is greater than 60%.

18. A method of delivering an active agent to a patient in need thereof comprising administering a dry powder using the inhalation system of claim 5 , the microparticles having been loaded with a drug or active agent.

19. The inhalation system of claim 5 wherein the active agent comprises an endocrine hormone selected from the group consisting of insulin, parathyroid hormone, calcitonin, glucagon, glucagon-like peptide-1, oxyntomodulin, an analog or active fragment of said endocrine hormone.

20. The inhalation system of claim 5 wherein the active agent comprises insulin.