Sustained release pharmaceutical formulation for inhalation

A dry powder sustained release pharmaceutical formulation for delivery to the lungs of a patient by inhalation comprising:

• porous microparticles having a volume average diameter between 1 μm and 5 μm, the porous microparticles being formed of at least a pharmaceutical agent, a matrix material, and a surfactant;
• and
• a pharmaceutically acceptable bulking agent blended with the porous microparticles,
• wherein upon inhalation of the formulation into the lungs a majority of the pharmaceutical agent is released no earlier than about 2 hours and no later than about 24 hours following inhalation.

A method for making a dry powder formulation for inhalation and sustained release of pharmaceutical agent comprising:

• dissolving a matrix material in a volatile solvent to form a solution;
• adding a pharmaceutical agent to the solution to form an emulsion, suspension, or second solution;
• and
• removing the volatile solvent from the emulsion, suspension, or second solution to yield porous microparticles which comprise the pharmaceutical agent and the matrix material, wherein upon inhalation of the formulation into the lungs a therapeutically or prophylactically effective amount of the pharmaceutical agent is released from the microparticles in the lungs for at least 2 hours.

A method for making a dry powder formulation for inhalation and sustained release of pharmaceutical agent comprising:

• dissolving a matrix material in a volatile solvent to form a solution;
• adding a pharmaceutical agent to the solution;
• combining at least one pore forming agent with the pharmaceutical agent in the solution to form an emulsion, suspension, or second solution;
• and
• removing the volatile solvent and the pore forming agent from the emulsion, suspension, or second solution to yield porous microparticles which comprise the pharmaceutical agent and the matrix material, wherein upon inhalation of the formulation into the lungs a therapeutically or prophylactically effective amount of the pharmaceutical agent is released from the microparticles in the lungs for at least 2 hours.