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EP-4208220-B1 - MULTI-STAGE INJECTION DEVICE

EP4208220B1EP 4208220 B1EP4208220 B1EP 4208220B1EP-4208220-B1

Inventors

  • GAVIN, WILLIAM, DAVID

Dates

Publication Date
20260506
Application Date
20210827

Claims (11)

  1. An injection device configured to administer a medicament from a syringe (12), the injection device comprising: a syringe (12) having a syringe barrel (12a) at least partially filled with the medicament and sealed by a piston (14a), a flange (12c) extending radially from a proximal end of the syringe barrel (12a) and a needle (12b) extending distally from a distal end of the syringe barrel (12a), the injection device comprising: a lower housing (18); a spring retaining sleeve (32) supported by the lower housing (18); a syringe spring (34) at least partially received within the spring retaining sleeve (32), wherein the syringe spring (34) is configured to support an underside of the flange (12c) of the syringe (12) when installed so as to support the syringe (12) within the lower housing (18) such that the needle (12b) protrudes from a distal end of the lower housing (18), wherein the syringe spring (34) is configured to define a stiffness resulting in a spring compression force that is less than a force of static friction between the piston (14a) and the syringe barrel (12a) when the syringe (12) is installed within the lower housing (18); a needle guard (26) in sliding engagement with the lower housing (18), the needle guard (26) being movable relative to the lower housing (18) in a proximal direction from a first position, wherein a distal end of the needle guard (26) extends beyond the distal end of the lower housing (18), is spaced from a proximal end of the lower housing (18) by a first interval and is configured to conceal a distal tip of the needle (12b) when the syringe (12) is installed in the lower housing (18), to a second position, wherein the distal end of the needle guard (26) is spaced from the proximal end of the lower housing (18) by a second interval that is less than the first interval; a needle guard spring (27) configured to engage the lower housing (18) and the needle guard (26) to bias the needle guard (26) distally relative to the lower housing (18); an upper housing (16) in sliding engagement with the lower housing (18) and movable relative to the lower housing (18) in a distal direction from a pre-use position to a dispensed position; and a plunger rod (14) configured to engage the piston (14a), wherein: proximal movement of the needle guard (26) from the first position to the second position is configured to extend the distal tip of the needle (12b) distally beyond the needle guard (26) by a first distance when installed; and subsequent distal movement of the upper housing (16) relative to the lower housing (18) from the pre-use position toward the dispensed position is configured to translate therewith the plunger rod (14) to: (i) first compress the syringe spring (34), and, in turn, distally translate the needle (12b) relative to the lower housing (18) when installed, such that the distal tip of the needle (12b) extends distally beyond the needle guard (26) by a second distance that is greater than the first distance, and (ii) thereafter, further advance the piston (14a) through the syringe barrel (12a) when installed to dispense the medicament from the syringe (12).
  2. The injection device of claim 1, wherein the spring retaining sleeve (32) defines: a passage extending therethrough from a proximal end to a distal end, the syringe spring (34) being positioned at least partially within the passage; and a support disposed within the passage to support a distal end of the syringe spring (34).
  3. The injection device of any one of the preceding claims, wherein the upper housing (16) is positionally locked relative to the lower housing (18) when the upper housing (16) reaches the dispensed position.
  4. The injection device of claim 3, wherein the needle guard spring (27) is configured to bias the needle guard (26) from the second position to a third position when the upper housing (16) is locked in the dispensed position, wherein, in the third position: the distal end of the needle guard (26) extends beyond the distal end of the lower housing (18), the distal end of the needle guard (26) is spaced from the proximal end of the lower housing (18) by a third interval greater than the first interval, and the distal end of the needle guard (26) is configured to conceal the distal tip of the needle (12b) of the syringe (12) when installed.
  5. The injection device of claim 4, wherein the needle guard (26) is positionally locked relative to the upper and lower housing (18) in the third position thereof.
  6. The injection device of any one of the preceding claims, wherein the first distance is less than 10 mm.
  7. The injection device of any one of the preceding claims, wherein the second distance is at least 10 mm greater than the first distance.
  8. The injection device of claim 7, wherein the second distance is between approximately 10 mm and approximately 80 mm.
  9. The injection device of any one of the preceding claims, further comprising the syringe (12) installed within the lower housing (18).
  10. The injection device of any one of the preceding claims, wherein the upper housing (16) is prevented from distal movement relative to the lower housing (18) when the needle guard (26) is in the first position.
  11. The injection device of claim 10, wherein proximal movement of the needle guard (26) from the first position to the second position is configured to permit distal movement of the upper housing (16) relative to the lower housing (18).

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority from U.S. Provisional Patent Application No. 63/072,967, titled "Multi-Stage Injection Device", filed on September 1, 2020. BACKGROUND OF THE DISCLOSURE The disclosure generally relates to injection devices for administering parenteral medicament injections, and, more particularly, to injection devices containing pre-filled syringes. Conventional injection devices for administering parenteral medicament injections are designed to either accommodate a particularly sized syringe and/or needle or to administer the medicament at a generally single depth underneath the skin surface of a user/patient. One drawback of such injection devices is that different injection device components must be manufactured for each intended syringe and/or needle size for use therewith and intended needle depth. It would, therefore, be advantageous to manufacture an injection device capable of accommodating differently sized syringes and/or needles and capable of administering injections at different pre-determined objective depths underneath the skin surface while maximizing the number of common injection device components. BRIEF SUMMARY OF THE DISCLOSURE Briefly stated, the invention is directed to an injection device configured to administer a medicament from a syringe having a syringe barrel at least partially filled with the medicament and sealed by a piston, a flange extending radially from a proximal end of the syringe barrel, and a needle extending distally from a distal end of the syringe barrel. The device includes a lower housing, a spring retaining sleeve supported by the lower housing, and a syringe spring at least partially received within the spring retaining sleeve, wherein the spring is configured to support an underside of the flange of the syringe when installed so as to support the syringe within the lower housing such that the needle protrudes from a distal end of the lower housing. A needle guard is in sliding engagement with the lower housing, and is movable relative to the lower housing in a proximal direction from a first position, wherein a distal end of the needle guard extends beyond the distal end of the lower housing, is spaced from a proximal end of the lower housing by a first interval, and is configured to conceal a distal tip of the needle when the syringe is installed in the lower housing to a second position, wherein the distal end of the needle guard is spaced from the proximal end of the lower housing by a second interval that is less than the first interval. A needle guard spring is configured to engage the lower housing and the needle guard to bias the needle guard distally relative to the lower housing. An upper housing is in sliding engagement with the lower housing and movable relative to the lower housing in a distal direction from a pre-use position to a dispensed position. The upper housing may optionally be prevented from distal movement relative to the lower housing when the needle guard is in the first position. Proximal movement of the needle guard from the first position to the second position is configured to extend the distal tip of the needle distally beyond the needle guard by a first distance when installed. Optionally, proximal movement of the needle guard from the first position to the second position may also be configured to permit distal movement of upper housing relative to the lower housing. Subsequent distal movement of the upper housing relative to the lower housing from the pre-use position toward the dispensed position is configured to (i) first compress the syringe spring, and, in turn, distally translate the needle relative to the lower housing when installed, such that the distal tip of the needle extends distally beyond the needle guard by a second distance that is greater than the first distance, and (ii) thereafter, further advance the upper housing distally relative to the syringe when installed to dispense the medicament from the syringe. In one configuration, the spring retaining sleeve defines a passage extending therethrough from a proximal end to a distal end, the syringe spring being positioned at least partially within the passage. A flange extends radially from the proximal end and is configured to engage the lower housing to support the spring retaining sleeve. A support is disposed within the passage to support a distal end of the syringe spring. In any of the previous configurations, the syringe spring is configured to define a stiffness resulting in a spring compression force that is less than a force of static friction between the piston and the syringe barrel when the syringe is installed within the lower housing. In any of the previous configurations, the distal movement of the upper housing relative to the lower housing is configured to translate therewith a plunger rod engaging the piston, wherein distal translation of the plunger rod first causes the compression of the s