Syringes for prefilled and fill-at-use mixing and drug delivery
A mixing syringe including a valve mechanism is configured and configurable to enable one or more substances to be prefilled into the syringe. The valve mechanism may be an aspect of a distal seal assembly. Actuation of the valve mechanism permits opening of a fluid passage for mixing of the one or more substances, and a resulting mixed substance can be delivered by the syringe, for example, for administration of a pharmaceutical to a subject.
1. A syringe comprising:
a housing;
a plunger rod;
a ring seal having a passage, the ring seal being in sealing engagement with the housing; and
an insert engaged with the ring seal, the insert having a longitudinal channel, a substance passage aligned with the passage of the ring seal, and a radial shoulder which engages the ring seal to prevent movement of the insert with respect to the ring seal, the insert configured to translatably receive a distal end of the plunger rod;
wherein the distal end of the plunger rod is in sealing engagement with the passage of the ring seal when the plunger rod is in a distal position within the insert, and further wherein the plunger rod is not in sealing engagement with the ring seal when the plunger rod is in a proximal position within the insert.
2. The syringe of claim 1 , wherein the ring seal further includes a lip formation adjacent the passage.
3. The syringe of claim 2 , wherein the lip formation bears against an inner wall of the insert to prevent movement of the lip formation.
4. The syringe of claim 1 , wherein the insert further includes a locking groove extending circumferentially from the longitudinal channel.
5. The syringe of claim 4 , wherein the plunger rod further includes a protrusion and the protrusion of the plunger rod is disposed within the locking groove in the distal position and translation of the plunger rod with respect to the ring seal is restricted.
6. The syringe of claim 5 , wherein rotation of the plunger rod causes the protrusion to enter the longitudinal channel and thereby allows axial translation of the plunger rod with respect to the ring seal.
7. The syringe of claim 1 , wherein the plunger rod further includes a protrusion disposed within the longitudinal channel of the insert to guide translation of the plunger rod from the distal position to the proximal position.
8. The syringe of claim 7 , wherein the longitudinal channel of the insert has a distal stop and a proximal stop, the protrusion of the plunger rod being adjacent to the distal stop in the distal position and being adjacent to the proximal stop in the proximal position.
9. The syringe of claim 1 , wherein the plunger rod includes one or more circumferential ribs configured for engagement with the passage of the ring seal in the distal position.
10. The syringe of claim 1 , wherein a substance can pass through the ring seal with the plunger rod in the proximal position.
11. The syringe of claim 1 , further comprising a proximal seal, wherein the insert includes a connector adapted to irreversibly connect the ring seal to the proximal seal.