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EP-3927398-B1 - EXOSTRUCTURE TO ASSIST IN ACCURATE SYRINGE INJECTION

EP3927398B1EP 3927398 B1EP3927398 B1EP 3927398B1EP-3927398-B1

Inventors

  • KWOLEK, Marilyn
  • BLOCK, Jon

Dates

Publication Date
20260506
Application Date
20200219

Claims (8)

  1. A syringe exostructure comprising: a main body having an upper end and a lower end and being configured to removably receive a syringe (S) having a syringe barrel (BR) and a syringe plunger (SP) ; a drive plunger (206) reciprocatably mounted on the main body; a plunger bar (208) slidably disposed on drive plunger (206) and having an upper end configured to removably couple to the syringe plunger when the syringe is received on the main body; a drive pawl (230) at a lower end of the drive plunger (206), said drive pawl (230) configured to engage the plunger bar (208) to transfer downward motion to the plunger bar (208) as the drive plunger (206) is advanced downwardly and to disengage from the plunger bar (208) as the drive plunger (206) is retracted upwardly; and a locking pawl (216) fixed relative to the main body and configured to engage the plunger bar (208) and to allow the plunger bar (208) to be advanced downwardly by the drive plunger (206) as the drive plunger (206) is advanced downwardly but to prevent the plunger bar (208) from being retracted upwardly by the drive plunger (206) as the drive plunger is retracted upwardly, wherein the plunger bar (208) is slidably received in an axial channel (203) on the drive plunger (206), wherein the locking pawl (216) extends through a slot formed in the axial channel (203) of the drive plunger (206).
  2. A syringe exostructure as in claim 1, wherein the plunger bar (208) has a toothed ratchet surface which is engaged by both the drive pawl (230) and the locking pawl (216).
  3. A syringe exostructure as in claim 2, wherein the locking pawl (216) is formed as a living hinge (219) coupled to the main body and oriented relative to the toothed ratchet surface to allow downward movement of the plunger bar (208) relative to the main body and prevent upward movement of the plunger bar (208) relative to the main body.
  4. A syringe exostructure as in claim 3, wherein the drive pawl (230) is formed as a living hinge (231) at the lower end of the drive plunger (206) and is oriented relative to the toothed ratchet surface to cause downward movement of the plunger bar (208) relative to the main body as the drive plunger (206) is advanced and allow upward movement of the drive plunger (206) relative to the main body as the plunger bar (208) is held in place by the locking pawl (216).
  5. A syringe exostructure as in claim 1, wherein the drive pawl (230) comprises an assembly of a pair of pawls forming a cam mechanism pivotally attached to the drive plunger (206) and having tips configured to engage opposed inner surfaces of a channel formed in a bottom of the plunger bar (208).
  6. A syringe exostructure as in claim 5, wherein the tip of each pawl (230) of the drive pawl assembly comprises a toothed surface configured to engage a toothed surface formed on the inner surfaces of the channel formed in the bottom of the plunger bar (208), wherein the toothed surface on each pawl engages with the toothed surface on the inner surfaces of the channel as the drive plunger (206) is advanced and disengages with the toothed surface on the inner surfaces of the channel as the drive plunger (206) is retracted.
  7. A syringe exostructure as in claim 1, wherein the main body comprises a top shell (202b) having an upper surface with a barrel groove for removably receiving the syringe barrel and a bottom shell (201a) having an upper surface which carries the locking pawl (216) .
  8. A syringe exostructure as in claim 7, wherein the main body further comprises a T-handle (204) fixed to the main body with a slot for receiving a plunger button (SB) on the syringe (S).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention. The present invention relates generally to the field of medical devices. More specifically, the invention described herein relates to devices for delivering doses of a medicament from a syringe to a patient. Existing syringes utilize a plunger to push fluids out of a barrel through a needle and into an injection site. In the normal clinical setting, the practitioner's dominant free hand deploys the syringe with the thumb used to depress the plunger and the index and middle fingers placed on the flanges to provide direction and stabilization. Using the standard free- hand injection method, existing disposable syringes function well at delivering the total volume of the barrel as a single measured dose. However, a number of clinical interventions (e.g., botulinum toxin, deoxycholic acid, and hyaluronic acid) require that the contents of the syringe be apportioned reproducibly in separate, discrete units (i.e., doses) across multiple injection sites during the same procedure. Free-hand injection is an inaccurate and imprecise technique for delivering discrete units at multiple sites during the same procedure with expediency. This practice carries a risk of administering an incorrect dose to an injection site, even for an experienced medical professional. The risk of administering an incorrect dose utilizing the same syringe can be due to several factors that include the change in thumb force on the plunger required to reproducibly extrude the same volume of a fluid from a syringe as well as measurement errors when attempting to visualize the barrel markings at different angles. Therefore, a need exists for apparatus and methods for administering accurate volumetric units from a syringe filled with a medicament volume sufficient for multiple dosages. 2. Description of the Background Art. Background patents and publications include US2015025502; US4415101; US4022207; and US2491978. US 4022207 describes an actuator for a syringe. The actuator is formed with a main body shaped to support a syringe whose plunger is moved by a plunger actuator. A reciprocating finger actuatable pusher is mounted with the plunger actuator to the main body and a ratchet mechanism operative between the plunger actuator and the pusher provides discrete motions of the plunger actuator. A back motion inhibitor is employed in the form of a fibrous material capable of restraining reverse movement of the plunger actuator while allowing unobstructed operative movement thereof. US 2007/197976 describes a medication dispensing apparatus with a spring-driven locking feature includes a drive member movable in a distal direction within a housing, and a fluid container with a piston that is advanceable by the drive member when such drive member is moved distally by a driving means. The apparatus includes a latching element having a skid that is slidable along a surface of the drive member as the drive member passes distally during advancement. The drive member is arranged with the skid so as to maintain a latching lip of the latching element against a spring force in a first position free of the driving means during dose preparing and injecting prior to a final dose administration. The skid-engaging surface shifts distally of the skid such that the skid passes beyond a proximal end of that surface upon administration of a final dose, whereby the latching lip is urged by the spring force from the first position to a second position to physically lock the driving means to prevent further dose preparing and injecting. SUMMARY OF THE INVENTION The present invention is defined by the subject-matter of claim 1. Further embodiments are defined in the dependent claims. The present disclosure provides a syringe exostructure intended to receive a conventional syringe and needle assembly which is either pre-filled or adapted to be filled with a medicament, such as but not limited to botulinum toxin, deoxycholic acid, and hyaluronic acid, to be delivered to a patient in multiple, sequential small aliquots or doses, usually having a volume in a range from 0.01 ml to 0.1 ml, typically from 0.025 ml to 0.05 ml. A total number of small aliquots or doses may be in the range from 10 to 100, typically from 20 to 40, and the syringe may carry a total volume of medicament in the range from 0.3 ml to 10.0 ml. In a first aspect, the present disclosure comprises a syringe exostructure comprising a main body, a drive plunger, a plunger bar, a drive pawl, and a locking pawl. The main body has an upper end and a lower end, and is configured to removably receive a syringe having a syringe barrel and a syringe plunger. The syringe will typically be pre-filled with a selected medicament, and the drive plunger is reciprocatably mounted on the main body. The plunger bar is slidably mounted relative to the drive plunger and has an upper end configured to removably couple to the syringe plunger when the syringe is received on t