A method for preparing dry powder inhalation compositions which comprise two or more active ingredients and inert particulate excipient, and a method for adjusting the performance of such compositions is described. The method comprises mixing the first active ingredient and a portion of the second active ingredient with a first excipient to provide a first preblend, mixing the remaining portion of the second active ingredient with a second excipient to provide a second preblend, and finally mixing the first and the second preblends together, wherein the two excipient grades differ in their median particle size. The FPD level of second active ingredient can be adjusted simply by changing the ratio how it is divided between the first and the second excipient.
