Ratchet-based drive systems for more reliable and safer drug delivery are provided. The ratchet-based drive systems restrict angular movement and/or linear movement of components that cause a plunger to expel a liquid drug from a drug container. Movement of the components can be restricted to correspond to a predetermined or desired portion of the liquid drug. In the case that control of the drive system is lost or fails, the maximum amount of drug that could be delivered is limited to a known amount, thereby reducing the likelihood of an overdose.

An injection device for injecting medicament in a patient comprises a housing configured to house a fluid reservoir that has one of a plurality of volumes of medicament. An injection conduit fluidly coupled to the fluid reservoir defines a fluid pathway from the fluid reservoir to the patient. A firing mechanism is coupled to the fluid reservoir and is configured to expel the medicament from the fluid reservoir through the injection conduit. A volume setting mechanism is coupled to the firing mechanism and is configured to select the one of the plurality of volumes of medicament for the firing mechanism to expel. A dose setting mechanism is configured to select all or a fraction of the one of the plurality of volumes of medicament that is injected from the injection conduit when the firing mechanism is actuated.

An injection device incorporating a dose setting mechanism is presented where the dose setting mechanism contains a dose selector having one or more dose stops corresponding to a finite set of predetermined fixed doses, where the set of finite predetermined fixed doses includes a lowest fixed dose and one or more higher fixed doses, and where at least one of the one or more higher fixed doses is equal to the lowest fixed dose plus a fractional amount of the lowest fixed dose. The dose setting mechanism can further include a floating spline that is rotationally engaged with a snap element such that the snap element can rotate relative to the floating spline during both dose setting and dose delivery.

An injection device incorporating a dose setting mechanism is presented where the dose setting mechanism contains a dose selector having one or more dose stops corresponding to a finite set of predetermined fixed doses, where the set of finite predetermined fixed doses includes a lowest fixed dose and one or more higher fixed doses, and where at least one of the one or more higher fixed doses is equal to the lowest fixed dose plus a fractional amount of the lowest fixed dose. The dose setting mechanism can further include a floating spline that is rotationally engaged with a snap element such that the snap element can rotate relative to the floating spline during both dose setting and dose delivery.

A medication injection pen, including a housing, a dose set knob (DSK) comprising an internal key, and a dose stop member engaging the dose set knob. Rotation of the dose set knob to set a medication dose causes rotation of the dose stop member with respect to the dose set knob, and when the dose set knob is rotated to a last dose setting position, the dose stop member rotationally abuts the internal key thereby preventing further rotational movement of the dose set knob in a dose setting direction.

This disclosure refers to a dosing mechanism for use in a drug delivery device implementing a dialing mode and a dispensing mode, wherein the dosing mechanism comprises a dose button, a housing and a determination unit. The dose button is activatable by the user for dose dispense, causing displacement of an indicating element connected to the housing from a first position to a second position. The determination unit is adapted such that it detects the indicating element in its second position and thereby determines that the dosing mechanism is in the dispensing mode. With some embodiments, it is possible to distinguish between the dialing mode and the dispensing mode. Some embodiments further refer to a drug delivery device comprising the above dosing mechanism.

An injection device incorporating a dose setting mechanism is presented where the dose setting mechanism contains a dose selector having one or more dose stops corresponding to a finite set of predetermined fixed doses, where the set of finite predetermined fixed doses includes a lowest fixed dose and one or more higher fixed doses, and where at least one of the one or more higher fixed doses is equal to the lowest fixed dose plus a fractional amount of the lowest fixed dose. The dose setting mechanism can further include a floating spline that is rotationally engaged with a snap element such that the snap element can rotate relative to the floating spline during both dose setting and dose delivery.

A dose setting mechanism comprising a first element and a second element; the first element being moveable with respect to the second element; the first element and the second element being coupled by a ratchet mechanism allowing motion of the first element with respect to the second element from a first position to a second position only in a first direction while preventing motion in a second direction that is opposite to the first direction; once passing the second position, the first element being moveable with respect to the second element in the first direction and in the second direction.

Drug delivery devices and related methods of assembly are disclosed. The drug delivery device may include a housing, a container, a trigger member, and an interlock assembly. The trigger member may be selectively moveable relative to the housing to activate operation of at least one activatable element of the drug delivery device. The interlock assembly may include a lever mounted rotatably relative to the housing, a proximity sensor moveable between a first position extending beyond an exterior surface of the housing and a second position retracted toward the housing, and a rotational biasing member operably connected to the proximity sensor via the lever. When the proximity sensor is in the first position, the interlock assembly may limit movement of the trigger member relative to the housing. The rotational biasing member may be configured to exert a torque biasing the proximity sensor toward the first sensor position.

A medicine dispensing device and system for administering a selected drug. The medicine dispensing device includes a vessel configured to retain a drug to be dispensed. The medicine dispensing device may comprise a first series of zones of varying widths on a surface of the vessel, with each zone of the first series of zones corresponding to a pre-determined dose of the drug for a first medical condition wherein the first series of zones are correlated to a first series of values of a physical characteristic of a patient; and a second series of zones of varying widths on the surface of the vessel, with each zone of the second series of zones corresponding to a pre-determined dose of the drug for a second medical condition wherein the second series of zones are correlated to a second series of values of the physical characteristic of a patient.