Patent ID: 8039431

Claim:
A method of preparing a dry powder medicament with an improved pharmaceutic property, comprising the steps of: (a) providing a solution of a diketopiperazine having acidic or basic side chains; (b) providing a solution of insulin; (c) forming particles of the diketopiperazine by adjusting the pH of the solution, resulting in a suspension of particles of the diketopiperazine with acidic or basic side chains in a solvent; (d) combining the diketopiperazine particles and the insulin solution; and (e) after steps (a)-(d), removing the solvent by spray drying to obtain a dry powder, wherein the dry powder obtained by spray drying has an improved pharmaceutic property as compared to a dry powder obtained by removing solvent by lyophilization, wherein the improved pharmaceutic property is selected from the group consisting of improved stability of the insulin, increased density of the powder, and improved aerodynamic performance of the dry powder.