Delivery of Active Agents

A method of improving the effectiveness of a labile active agent in a patient comprising:

• administering by inhalation a pharmaceutical composition comprising a diketopiperazine microparticle and one or more active agents, wherein about 35% to about 75% of the microparticles have an aerodynamic diameter of less than 5.8 μm;
• wherein the labile active agent when administered by injection is subject to degradation in the patient as a result of exposure to peripheral tissue, vascular venous tissue, or liver metabolism, and said labile active agent effectiveness is reduced by said degradation prior to reaching a site of action.

A method of administering a prostaglandin to a patient in need thereof comprising:

• administering to said patient an inhalable dry powder pharmaceutical composition comprising diketopiperazine microparticles and said prostaglandin, wherein about 35% to about 75% of the diketopiperazine microparticles have an aerodynamic diameter of less than 5.8 μm,
• wherein the prostaglandin is subject to degradation in a patient as a result of exposure to peripheral tissue, vascular venous tissue, or liver metabolism when administered by other routes of administration.

A method of treating pulmonary disease to a patient in need thereof comprising:

• administering to said patient an inhalable dry powder formulation comprising a therapeutically effective amount of a prostaglandin using a breath-powered dry powder inhaler, wherein said formulation comprises from about 0.01 mg to about 3 mg of said prostaglandin.