A process for preparing a powder formulation for inhalation for use in a dry powder inhaler, said powder comprising: a carrier comprising: (a) 80 to 95 percent by weight, based on the total weight of said carrier, of coarse particles of alpha-lactose monohydrate having a mean particle size of at least 175 μm and a mass diameter comprised between 100 and 600 micron; and (b) 19.6 to 4.9 percent by weight, based on the total weight of said carrier, of micronized particles of alpha-lactose monohydrate, and 0.1 to 0.4 percent by weight, based on the total weight of said carrier, of magnesium stearate; and micronized particles of glycopyrronium bromide, formoterol fumarate dihydrate, and beclometasone dipropionate as active ingredients, said process comprising: (i) mixing all of said coarse particles of alpha-lactose monohydrate, all of said magnesium stearate, a first portion of said micronized particles of alpha-lactose monohydrate, all of said micronized particles of the active ingredients in a vessel of a shaker mixer at a speed of rotation not lower than 16 r.p.m. for a time of not less than 60 minutes, to obtain a first mixture; and (ii) adding the remaining part of said micronized particles of alpha-lactose monohydrate to said first mixture, to obtain a second mixture, and mixing said second mixture at a speed of rotation not lower than 16 rpm for a time of at least 120 minutes; wherein said first portion of said micronized particles of alpha-lactose monohydrate is comprised between 40% and 60%, based on the total weight of all of said micronized particles of alpha-lactose monohydrate. a carrier comprising: (a) 80 to 95 percent by weight, based on the total weight of said carrier, of coarse particles of alpha-lactose monohydrate having a mean particle size of at least 175 μm and a mass diameter comprised between 100 and 600 micron; and (b) 19.6 to 4.9 percent by weight, based on the total weight of said carrier, of micronized particles of alpha-lactose monohydrate, and 0.1 to 0.4 percent by weight, based on the total weight of said carrier, of magnesium stearate; and (a) 80 to 95 percent by weight, based on the total weight of said carrier, of coarse particles of alpha-lactose monohydrate having a mean particle size of at least 175 μm and a mass diameter comprised between 100 and 600 micron; and (b) 19.6 to 4.9 percent by weight, based on the total weight of said carrier, of micronized particles of alpha-lactose monohydrate, and 0.1 to 0.4 percent by weight, based on the total weight of said carrier, of magnesium stearate; and micronized particles of glycopyrronium bromide, formoterol fumarate dihydrate, and beclometasone dipropionate as active ingredients, said process comprising: (i) mixing all of said coarse particles of alpha-lactose monohydrate, all of said magnesium stearate, a first portion of said micronized particles of alpha-lactose monohydrate, all of said micronized particles of the active ingredients in a vessel of a shaker mixer at a speed of rotation not lower than 16 r.p.m. for a time of not less than 60 minutes, to obtain a first mixture; and (ii) adding the remaining part of said micronized particles of alpha-lactose monohydrate to said first mixture, to obtain a second mixture, and mixing said second mixture at a speed of rotation not lower than 16 rpm for a time of at least 120 minutes; wherein said first portion of said micronized particles of alpha-lactose monohydrate is comprised between 40% and 60%, based on the total weight of all of said micronized particles of alpha-lactose monohydrate. (i) mixing all of said coarse particles of alpha-lactose monohydrate, all of said magnesium stearate, a first portion of said micronized particles of alpha-lactose monohydrate, all of said micronized particles of the active ingredients in a vessel of a shaker mixer at a speed of rotation not lower than 16 r.p.m. for a time of not less than 60 minutes, to obtain a first mixture; and (ii) adding the remaining part of said micronized particles of alpha-lactose monohydrate to said first mixture, to obtain a second mixture, and mixing said second mixture at a speed of rotation not lower than 16 rpm for a time of at least 120 minutes; wherein said first portion of said micronized particles of alpha-lactose monohydrate is comprised between 40% and 60%, based on the total weight of all of said micronized particles of alpha-lactose monohydrate.