Patent ID: 7803404

Claim:
A method of promoting binding of an active agent to a preformed crystalline diketopiperazine microparticle in suspension comprising the steps in the sequence set forth of: i) modifying the chemical potential of the active agent wherein said modifying allows for an energetically favorable interaction between the active agent and the preformed crystalline diketopiperazine microparticle independent of removal of solvent; followed by ii) allowing adsorption of the active agent onto the surface of the preformed crystalline diketopiperazine microparticle; wherein said modifying step causes said adsorbing of said active agent onto a surface of said preformed crystalline diketopiperazine microparticle to provide a coating of said active agent on said preformed crystalline diketopiperazine microparticle; and wherein said preformed crystalline diketopiperazine microparticle does not comprise an active agent.