COMPOSITION AND METHOD FOR INHALATION

1 . A pharmaceutical dry powder composition comprising a treprostinil dose in an amount of up to 200 μg and one or more pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier and/or excipients.

2 . The pharmaceutical dry powder composition of claim 1 , wherein the one or more pharmaceutically acceptable carrier and/or excipient is a diketopiperazine.

3 . The pharmaceutical dry powder composition of claim 2 , wherein the diketopiperazine is fumaryl diketopiperazine and comprises microcrystalline particles comprising crystallites of the diketopiperazine and the tresprostinil.

4 . The pharmaceutical dry powder composition of claim 1 , wherein the treprostinil is from about 1 μg to about 180 μg in the dry powder composition.

5 . The pharmaceutical dry powder composition of claim 1 , wherein the pharmaceutical dry powder composition is in substantially crystalline form.

6 . The pharmaceutical dry powder composition of claim 1 , wherein the one or more pharmaceutically acceptable carrier and/or excipients is selected from lactose, mannose, sucrose, mannitol, trehalose, sodium citrate, trisodium citrate, zinc citrate, glycine, L-leucine, isoleucine, trileucine, sodium tartrate, zinc tartrate, methionine, vitamin A, vitamin E, sodium chloride, zinc chloride, polyvinylpyrrolidone, or polysorbate 80.

7 . The pharmaceutical dry powder composition of claim 6 , wherein the one or more pharmaceutically acceptable carrier and/or excipient are sodium citrate, sodium chloride, leucine or isoleucine, and trehalose.

8 . The pharmaceutical dry powder composition of claim 7 , further comprising polysorbate 80.

9 . The pharmaceutical dry powder composition of claim 3 , wherein microcrystalline particles have a specific surface area ranging from about 59 m 2 /g to about 63 m 2 /g.

10 . The pharmaceutical dry powder composition of claim 3 , wherein microcrystalline particles have a pore size ranging from about 23 nm to about 30 nm.

11 . A method of treating pulmonary arterial hypertension comprising administering to a patient in need of treatment by oral inhalation using a dry powder inhaler comprising a dry powder composition comprising up to 200 μg of treprostinil or a pharmaceutically acceptable salt thereof, and/or one or more pharmaceutically acceptable carrier and/or excipient.

12 . The method of treating pulmonary arterial hypertension of claim 11 , wherein the one or more pharmaceutically acceptable carrier and/or excipients is selected from the group consisting of fumaryl diketopiperazine, lactose, mannose, sucrose, mannitol, trehalose, sodium citrate, trisodium citrate, zinc citrate, glycine, L-leucine, isoleucine, trileucine, sodium tartrate, zinc tartrate, methionine, vitamin A, vitamin E, sodium chloride, zinc chloride, polyvinylpyrrolidone, and polysorbate 80.

13 . The method of treating pulmonary arterial hypertension of claim 12 , wherein the one or more pharmaceutically acceptable carrier and/or excipient are sodium citrate, sodium chloride, leucine or isoleucine, and trehalose.

14 . The method of treating pulmonary arterial hypertension of claim 11 , wherein the one or more pharmaceutically acceptable carrier and/or excipient is fumaryl dikepiperazine.

15 . The method of treating pulmonary arterial hypertension of claim 11 , wherein the dry powder composition is administered in at least one inhalation in less than 10 seconds.

16 . A dry powder inhaler comprising a movable member to load an enclosure and configure the container to attain a dosing configuration, wherein said enclosure comprises the pharmaceutical dry powder composition of claim 1 .

17 . The dry powder inhaler of claim 16 , wherein the enclosure comprises a cartridge consisting of a lid and a container.