Containers for incrementally dispensing pressurized contents are described. The containers comprise a vessel suited to contain pressurized contents, a port integral with the vessel and through which pressurized contents contained in the vessel can be released from the vessel, preferably incrementally in approximately equal amounts, and a measuring device disposed in or otherwise associated with the vessel such that the quantity or amount of contents in the vessel can be measured or assessed. The measuring device senses ambient conditions in the vessel and, directly or with other components, indicates, for example, the amount of pressurized contents remaining in the vessel and displaying it to an observer. With appropriate ancillary components, the measuring device also enables the amount of contents actually released from the vessel during a particular actuation to be compared to a theoretical constant. Also, additionally, the devices of the invention may also include time
logging capability (alone or in conjunction with the capability to log other data) the actuation of the dispensing valve for comparison to a prescribed method. Accordingly, devices for incrementally dispensing pressurized contents from such containers are also described. Such devices further comprise a metering value for dispensing pressurized contents from the vessel. In preferred embodiments, each actuation of the metering valve results in release of a pre-determined quantity of the vessel contents. For example, in embodiments wherein the pressurized contents comprise a therapeutic composition, the instant devices include improved Metered
Dose Inhalers (MDIs) for delivery of predetermined doses of a therapeutic composition to a patient, wherein the MDIs provide for sensing of the amount, for example, of the therapeutic composition remaining in the vessel after each actuation of the metering valve.