Patent ID: 8607786

Claim:
A drug delivery apparatus for releasing a drug in aerosolized form into an inhaled airstream of a person, the drug delivery apparatus comprising: a processor programmed to obtain an expected inhalation length; to obtain an end inhalation amount of time that corresponds to a specific minimum lung residence time such that drug delivered to the person at least the end inhalation amount of time before the end of an inhalation will have an aerosol hold within the lungs of the person for at least the minimum lung residence time, wherein the specific minimum lung residence time is 0.5 seconds; to determine a pulse length for a pulse of release of the drug based on a subtraction of the end inhalation amount of time from the expected inhalation length; and to release the pulse of the drug for the pulse length so that the pulse ends the end inhalation amount of time before the obtained expected inhalation length expires to effect the aerosol hold of the drug delivered in the pulse in which the minimum lung residence time of the drug delivered in the pulse is at least 0.5 second; wherein the processor is programmed to release the pulse of the drug for a pulse length so that the pulse is for a pre-set proportion of an expected period of inhalation in the event that a breathing threshold is not reached.