A metered dose inhaler canister combination comprises a canister configured 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 said open end and extending generally distally from said 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 configured to receive the canister therein, the waist defining an aperture of constricted width configured to receive the canister therethrough, and a second cooperating formation extending generally distally from said waist, wherein the respective first and second cooperating formations adopt an engaged condition in which the canister is retained within the shroud.
