Disclosed is a method to reduce deposition of particles at initial in a metered dose inhaler comprising a canister and metering valve, containing a suspension aerosol formulation comprising particles of formoterol fumarate dihydrate and fluticasone propionate suspended in an HF A propellant, the method reducing deposition of particles on the surfaces of the canister and the metering valve, and the method comprising the step of adding a wetting agent to the formulation, wherein the wetting agent is selected from the group consisting of ethanol, diols or polyols, such as propylene glycol, glycerol, butandiol and mixtures thereof.
