Diketopiperazine microparticles with defined specific surface areas

1. A dry powder pharmaceutical composition comprising inhalable 3,6-di(N-fumaryl-4-aminobutyl)-2,5-diketopiperazine microparticles; wherein each of the microparticles has a specific surface area of 35 m 2 /g to about 67 m 2 /g and comprises an active agent.

2. The dry powder of claim 1 , wherein the active agent is vasoactive agent, a neuroactive agent, an immunomodulating agent, a cytotoxic agent, an antibiotic, an antiviral agent, an antigen, and infectious agent, an inflammatory mediator, a hormone, or a cell surface antigen.

3. The dry powder of claim 1 , wherein the active agent is a prostaglandin.

4. The dry powder of claim 3 , wherein the prostaglandin is PG I 2 .

5. The dry powder of claim 1 , wherein the active agent is about 0.01% to about 20% of the weight of the microparticles.

6. A dry powder for inhalation comprising microparticles of a diketopiperazine of the formula:

and a prostaglandin; wherein the microparticles have a specific surface area of 35 m 2 /g to about 67 m 2 /g.

7. The dry powder of claim 6 , wherein the prostaglandin is PG I 2 or an analog thereof.

8. A dry powder for inhalation comprising microparticles of a diketopiperazine of the formula:

and granulocyte macrophage colony stimulating factor; wherein the microparticles have a specific surface area of 35 m 2 /g to about 67 m 2 /g.

9. A dry powder inhaler comprising a dry powder formulation comprising microparticles of a fumaryl diketopiperazine (FDKP) having the formula:

wherein the FDKP microparticles have a specific surface area of 35 m 2 /g to about 67 m 2 /g and one or more than one active agents.

10. The dry powder inhaler of claim 9 , wherein the one or more active agents is a prostaglandin.

11. The dry powder inhaler of claim 10 , wherein the one or more active agent prostaglandin PG 12 or an analog thereof.

12. The dry powder inhaler of claim 9 wherein the one or more active agent is granulocyte macrophage colony stimulating factor.