Glass Distal Tip Coupling for Drug Delivery Leak Prevention

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Solution Overview

Problem

Conventional drug delivery devices with plastic adaptors face issues due to deformation under aging and temperature conditions, leading to insecure connections and potential breakage of glass distal tips, which can result in leaks and incorrect dosing.

Innovation Solution

A drug delivery device with a glass distal tip featuring a specific design where the coupling portion has a greater external diameter than the distal portion, and an adaptable ring that radially expands for secure friction contact, combined with a roughened surface for enhanced friction, preventing rotation and translation, and a design that minimizes sharp angles to enhance resistance to breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a plastic adaptor is used to connect the distal tip to the connector, then the connection is easier to manufacture, but the adaptor deforms under aging and temperature conditions leading to insecure connections

Engineering Contradiction:
Improveadaptor manufacturingVSAvoidconnection security
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the material parameter from plastic to glass, which maintains dimensional stability under aging and temperature conditions. The glass distal tip with a coupling portion having a greater external diameter than the distal portion creates a geometric parameter change that prevents adaptor deformation and ensures secure connection throughout the device lifecycle.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the coupling portion has a greater external diameter than the distal portion, then the adaptor connection is more secure, but the device complexity increases

Engineering Contradiction:
Improveadaptor connection securityVSAvoiddistal tip structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The distal tip is segmented into distinct functional portions: a distal portion for product ejection and a coupling portion for adaptor connection. This segmentation allows each portion to be optimized for its specific function while maintaining overall structural integrity through the continuous glass material.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the outer surface is roughened to enhance friction, then the adaptor connection is more secure, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveadaptor friction contactVSAvoidsurface roughness control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The roughening treatment is applied locally only to the outer surface of the coupling portion where adaptor contact occurs, rather than the entire distal tip. This localized treatment enhances friction where needed while maintaining manufacturing feasibility and not affecting other functional areas of the glass structure.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Ensures a secure, reproducible, and leak-proof connection between the drug delivery device and connectors, while maintaining the mechanical strength and resistance to breakage of the glass distal tip, even after sterilization.

Implementation Method 1

The adaptor (8) comprises a ring (9) provided with an inner projection (10) extending radially inwardly... The ring (9) is radially and outwardly expandable from a rest position, in which said one inner projection (10) defines a first internal diameter Dr of said ring, and a stressed position, in which said one inner projection (10) defines a second internal diameter Ds of the ring

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The inner surface (10a) of the inner projection (10) is capable of cooperating with an outer surface (7a) of the coupling portion (7), when the adaptor (8) is fitted on the distal tip (3), so as to prevent rotational and translational movement of the adaptor (8) with respect to the distal tip (3)... The outer surface (7a) of the coupling portion (7) is partially provided with a roughening agent... thereby improving the friction force between the adaptor (8) and the distal tip (3)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2445556B1Improved luer connector
Publication Date: 2019.05.15 BECTON DICKINSON FRANCE SAS
  • EP2445556B1 patent drawingFigure 1~2B
  • EP2445556B1 patent drawingFigure 3A~3B
  • EP2445556B1 patent drawingFigure 4~5

AI summary

The invention relates to a drug delivery device comprising a container for a product, said container comprising a distal tip (3) having a longitudinal axis A and a channel (4) providing a passageway for the transfer of said product, the outer surface of said distal tip (3) comprising a proximal portion (5) and a distal portion (6) linked to each other by a coupling portion (7), said proximal portion (5), distal portion (6) and coupling portion (7) being aligned on said longitudinal axis A, characterized in that the greatest external diameter of said coupling portion (7) is greater than the greatest external diameter of said distal portion (6) on a length L measured along said longitudinal axis A at least equal to 1 mm. The invention also relates to an assembly (101) comprising such a drug delivery device and an adaptor (8).