Passive Needle Guard for Reconstitution Safety

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Solution Overview

Problem

Current syringe systems for reconstituting lyophilized drugs expose users to the risk of needle sticks and do not adequately prevent syringe reuse, as existing safety mechanisms often activate prematurely during the reconstitution process, interfering with the administration of the therapeutic agent.

Innovation Solution

A syringe system with a passive needle guard that remains inactive during reconstitution and automatically activates after drug administration, using a radial plunger mechanism to extend a shield over the needle, preventing accidental activation during mixing and ensuring safety post-injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a passive needle guard is used with syringes for reconstitution, then needle safety is improved after injection, but the safety shield activates prematurely during the reconstitution process

Engineering Contradiction:

Improveneedle safetyVSAvoidreconstitution process

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The plunger is segmented into two distinct functional portions: a first portion that contacts the trigger finger during reconstitution (causing minimal lateral movement that does not activate the shield), and a second portion that contacts the trigger finger during injection (causing sufficient lateral movement to activate the shield). This segmentation allows the same plunger to perform different functions at different stages without premature activation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the plunger have different contact characteristics with the trigger finger. The first portion (reconstitution side) is designed to contact the trigger finger in a manner that produces insufficient lateral movement for activation, while the second portion (injection side) is designed to produce sufficient lateral movement. This local differentiation in contact quality enables stage-specific functionality.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If the plunger is designed to activate the safety shield during reconstitution, then needle protection is achieved, but the syringe cannot be used to administer the therapeutic agent

Engineering Contradiction:

Improveneedle stick riskVSAvoiddrug administration capability

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The trigger finger is designed with elastic properties, allowing it to dynamically respond to different magnitudes of lateral force. During reconstitution, the first plunger portion applies minimal lateral force that elastically deflects the trigger finger without releasing the shield. During injection, the second plunger portion applies sufficient lateral force to overcome the elastic resistance and release the shield. This dynamic response enables selective activation based on force magnitude.

Inventive Principle:

Principle #15Dynamics

3Reliability

If a needle guard system is implemented, then accidental needle sticks are prevented, but the system complexity increases

Engineering Contradiction:

Improveaccidental needle stick preventionVSAvoidsyringe system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The needle guard system is self-activating through the plunger's own motion during the injection process. The second portion of the plunger automatically contacts the trigger finger and activates the shield without requiring any additional user action, separate mechanisms, or external triggers. The system uses the inherent mechanical energy of the plunger advancement to activate the safety feature, eliminating the need for separate activation mechanisms.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9044378B2Anti-needle stick safety device or system for use with drugs requiring reconstitution

Publication Date: 2015.06.02 SAFETY SYRINGES INC

AI summary

The present disclosure describes a needle guard device or system that can be used with drugs requiring reconstitution. The needle guard is preferably a passive needle guard that can be used during reconstitution without activating the safety mechanism. Following administration of the medication, the needle guard shields a user from inadvertent needle sticks by extending a protective shield over the needle.