Abstract: A metered dose inhaler canister combination includes a canister constructed for containing a pharmaceutical composition, the canister having a canister base, a side wall extending from the canister base, an open end distal from the base and a first cooperating formation arranged at the open end and extending generally distally from the canister base; a shroud having a shroud base and a side wall extending from the shroud base to a waist, the base and side wall defining a vessel constructed to receive the canister therein, the waist defining an aperture of constricted width constructed to receive the canister therethrough, and a second cooperating formation extending generally distally from the waist, wherein the respective first and second cooperating formations adopt an engaged condition in which the canister is retained within the shroud.