A metered dose inhaler for providing a dose of aerosol for controlled inhaled drug delivery, the dose of aerosol comprising a prescribed dose of biologically active material aerosolized in a propellant and the aerosol having a predetermined size distribution, the metered dose inhaler comprising: (a) a metering valve operable to release a metered amount of pressurized biologically active material and propellant from a canister, wherein the metering valve comprises an electromechanical valve or comprises a mechanical valve provided with an electromechanical actuator; characterized in that the metered dose inhaler further comprises (b) a heater arranged downstream of the metering valve; (c) an aerosol outlet from which an aerosol of the biologically active material is released for inhalation, arranged downstream of the heater; (d) a temperature sensor operable to sense the metered dose inhaler temperature; and (e) a controller; the controller comprising: (i) a digital processor operable to control the electromechanical metering valve or electromechanical actuator of the metering valve to release a metered dose of the biologically active material and propellant from the canister and operable to actuate the heater to heat biologically active material and propellant released by the metering valve; (ii) a memory operable to store data for generating the prescribed dose of the biologically active material in an aerosol having the predetermined size distribution based on sensed operating conditions including the metered dose inhaler temperature; (iii) a program operable to control the digital processor to operate the electromechanical metering valve or electromechanical actuator of the metering valve to release a metered dose of the biologically active material and to operate the heater to generate the prescribed dose of the biologically active material in an aerosol having the predetermined size distribution for release from the aerosol outlet under the sensed operating conditions including the metered dose inhaler temperature sensed by the temperature sensor. (a) a metering valve operable to release a metered amount of pressurized biologically active material and propellant from a canister, wherein the metering valve comprises an electromechanical valve or comprises a mechanical valve provided with an electromechanical actuator; characterized in that the metered dose inhaler further comprises (b) a heater arranged downstream of the metering valve; (c) an aerosol outlet from which an aerosol of the biologically active material is released for inhalation, arranged downstream of the heater; (d) a temperature sensor operable to sense the metered dose inhaler temperature; and (e) a controller; (i) a digital processor operable to control the electromechanical metering valve or electromechanical actuator of the metering valve to release a metered dose of the biologically active material and propellant from the canister and operable to actuate the heater to heat biologically active material and propellant released by the metering valve; (ii) a memory operable to store data for generating the prescribed dose of the biologically active material in an aerosol having the predetermined size distribution based on sensed operating conditions including the metered dose inhaler temperature; (iii) a program operable to control the digital processor to operate the electromechanical metering valve or electromechanical actuator of the metering valve to release a metered dose of the biologically active material and to operate the heater to generate the prescribed dose of the biologically active material in an aerosol having the predetermined size distribution for release from the aerosol outlet under the sensed operating conditions including the metered dose inhaler temperature sensed by the temperature sensor.