Metered dose inhalator

An assembly with a metered dose inhalation canister containing a pre-determined number of doses of an aerosol formulation, for delivery orally or intra-nasally, which comprises;

• (a) a hollow closed tube having
• (i) a first open end adapted by size and configuration to receive a spray stem of an aerosol inhalation canister;
• (ii) a second open end adapted by size and configuration to couple with an oral or nasal orifice of a mammal;
• (b) a spray-directing element fixedly located within said tube hollow, and having continuous communication with the first open end and the second open end, for directing sprays of the formulation through a portion of the hollow and out of the second open end of said tube, when the inhalation canister is assembled with the apparatus and activated by a user;
• (c) a metered dose inhalation canister slidably mounted in the first open end of the tube for delivery of a metered dose to the spray-directing element;
• (d) microelectronic means associated with the tube for indicating the number of doses remaining in the canister, after each activation;
• and
• (e) switch means for activating said microelectronic means, said switch means being isolated from exposure to the tube hollow;
• said microelectronic means being enclosed within a hermetically sealed sleeve housing, mountable on the canister and adapted by size and configuration to slide over the tube exterior.