Cassette for an autoinjector and related methods
A cassette for a drug delivery device is described that includes a sleeve, a syringe having a barrel disposed in the sleeve, and a plunger-stopper slidably disposed within the barrel. An end cap is adapted to couple to the sleeve to secure the syringe in the sleeve. The cassette further includes a spacer that is sized to be slidably moved within the barrel and the spacer is disposed distal to the plunger-stopper to be engaged by a plunger rod to slide within the barrel and engage the plunger-stopper. In some forms, the spacer can be coupled to the end cap.
1 . A cassette fer a drug delivery device, the cassette comprising:
a housing:
a drive mechanism disposed at least partially within the housing and comprising a plunger rod configured to move relative to the housing during a drug extrusion operation; and
a cassette comprising:
a sleeve having a proximal end and a distal end;
a syringe disposed in the sleeve, the syringe comprising a barrel having a distal opening adjacent to the distal end of the sleeve;
a plunger-stopper slidably disposed within the barrel;
an end cap coupled to the distal end of the sleeve adjacent the distal opening of the barrel to secure the syringe in the sleeve; and
a spacer disposed distally of the plunger-stopper having a diameter approximately equal to a diameter of the plunger-stopper, the spacer configured and sized to be slidably moved within the barrel and adapted to be engaged by the plunger rod of the drive mechanism to slide within the barrel and engage the plunger-stopper, wherein, following assembly of the cassette within the housing and until the drug extrusion operation, the spacer is spaced from the plunger-stopper by a gap, and wherein the spacer is brought into initial contact with the plunger-stopper by movement of the plunger rod when the plunger rod moves to expel a drug from the syringe during the drug extrusion operation.
2 . The drug delivery device of claim 1 , wherein the spacer is disposed between the plunger-stopper and the end cap.
3 . The drug delivery device of claim 1 , wherein the spacer is disposed adjacent to the distal end of the barrel.
4 . The drug delivery device of claim 1 , where the end cap secures the spacer to the barrel prior to drug delivery.
5 . The drug delivery device of claim 1 , wherein the spacer comprises a cup-shaped body having a rearwardly opening cavity sized to receive a plunger rod therein, wherein the body further optionally comprises a plurality of ribs extending inwardly within the cavity.
6 . The drug delivery device of claim 1 , wherein the spacer is sized to frictionally engage an interior surface of the barrel to resist mass forces.
7 . The drug delivery device of claim 1 , wherein the spacer comprises a vent allowing air to flow past the spacer as the spacer is moved along the barrel, wherein the vent optionally comprises either (a) or (b), as follows:
(a) a plurality of passages extending between radial protrusions arrayed around a circumference of the spacer, or
(b) one or more longitudinal channels recessed within an outer surface of the spacer.
8 . The drug delivery device of claim 1 , wherein, following the assembly of the cassette within the housing and until the drug extrusion operation, the spacer is spaced from the plunger-stopper by the gap and engages the plunger rod.
9 . The drug delivery device of claim 1 , wherein the end cap comprises an interior breakaway portion, and the spacer is secured to the breakaway portion, wherein the spacer is optionally molded over the breakaway portion.
10 . The drug delivery device of claim 9 , wherein the breakaway portion comprises a disc, and an end wall of the spacer is molded over the disc.
11 . The drug delivery device of claim 9 , wherein the breakaway portion further comprises a side wall extending rearwardly from edges of the disc.
12 . The drug delivery device of claim 9 , wherein the sleeve comprises at least one receptacle, and the end cap comprises an elastomeric bumper adapted to contact a distal end of the syringe and at least one arm member for inserting into the at least one receptacle.
13 . The drug delivery device of claim 9 , further comprising a therapeutic product in the syringe.
14 . The drug delivery device of claim 13 , wherein the therapeutic product is Epogen®, Aranesp®, Enbrel® Neulasta®, Neupogen®, Nplate®, Vectibix®, Sensipar®, Xgeva®, Prolia®, an antibody to IL-17 Receptor A, antagonist of angiopoietin-2, a TNF blocker or inhibitor, etanercept, adalimumab, certolizumab, golimumab or infliximab.
15 . A method comprising:
providing an autoinjector comprising: a housing, and a drive mechanism disposed at least partially within the housing and comprising a plunger rod configured to move relative to the housing during a drug extrusion operation;
providing a cassette comprising:
a plunger-stopper disposed within a barrel of a syringe;
the syringe being disposed within a sleeve;
a spacer sized to be slidably received within the barrel rearwardly from the plunger-stopper, wherein the spacer is brought into initial contact with the plunger-stopper by movement of the plunger rod of the autoinjector when the plunger rod moves to expel a drug from the syringe during the drug extrusion operation; and
an end cap coupled to the sleeve to secure the syringe in the sleeve; and
assembling the cassette within a housing of the autoinjector such that, following the assembly of the cassette within the housing of the autoinjector and until the drug extrusion operation, the spacer is spaced from the plunger-stopper by a gap.
16 . The method of claim 15 , wherein mounting the spacer rearwardly from the plunger-stopper comprises disposing the spacer in the barrel of the syringe rearward of the plunger-stopper.
17 . The method of claim 15 , wherein mounting the spacer rearwardly from the plunger-stopper comprises coupling the spacer to the end cap, such that coupling the end cap to the sleeve aligns the spacer with the barrel.
18 . The method of claim 17 , wherein coupling the spacer to the end cap for the sleeve comprises molding the spacer over a breakaway portion of the end cap.
19 . The method of claim 15 , further comprising filling the syringe with a therapeutic product.
20 . The method of claim 15 , further comprising receiving a plunger rod of the autoinjector in a rearwardly open cavity of the spacer for the plunger rod to drive the spacer through the barrel to engage the plunger-stopper.
21 . The method of claim 15 , further comprising selecting the spacer from a plurality of available spacers, each of the plurality of available spacers having distinct dimensions.
22 . The method of claim 15 , following the assembly of the cassette within the housing and until the drug extrusion operation, the spacer is spaced from the plunger-stopper by the gap and engages the plunger rod.