Medication Delivery Device Cap Locking Mechanism

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Solution Overview

Problem

Conventional medication delivery devices lack a clear indication that the last dose has been delivered, leading users to attempt to extract remaining medication, which can result in incomplete dosing and potential contamination or leakage during disposal.

Innovation Solution

A medication delivery device featuring a cap that locks permanently after the last dose is delivered, preventing detachment and covering the drug compartment, thus clearly indicating the end of life and encapsulating any remaining medication, reducing the risk of incomplete dosing and leakage during disposal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cap remains detachable after the last dose is delivered, then users can access the drug compartment, but users may attempt to extract remaining medication leading to incomplete dosing and potential contamination

Engineering Contradiction:
Improvedosing accuracyVSAvoidcap accessibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The cap transitions from a detachable state during normal operation to a locked state after the last dose is delivered. The locking mechanism dynamically changes the cap's attachment status based on the delivery mechanism's state, preventing further removal attempts while maintaining ease of access during the device's functional life.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking mechanism receives feedback from the delivery mechanism about whether the last dose has been delivered. Based on this feedback, the cap automatically locks to prevent further access, ensuring that users cannot attempt to extract remaining medication after the device has completed its intended function.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If the cap is made permanently locked after the last dose, then contamination and leakage risks are reduced, but users lose the ability to remove the cap for proper disposal

Engineering Contradiction:
Improvecontamination riskVSAvoiddisposal convenience
Core Design Contradiction:
Object-affected harmful factorsVSEase of repair

Solution Approach 1:

The device is segmented into a reusable housing and a disposable cartridge assembly. The locking mechanism secures the cap to the cartridge assembly, not the entire device. This allows users to dispose of the locked cap with the cartridge while retaining the housing for refilling, maintaining disposal convenience while preventing contamination.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking mechanism is designed to be temporary and removable. After the last dose is delivered, the cap locks to prevent contamination during use and storage. When disposal is needed, the entire locked cap-cartridge assembly can be removed and discarded as a unit, while the housing is recovered and refilled.

Inventive Principle:
Principle #34Discarding and recovering

3Reliability

If lock-out features are provided in the delivery mechanism, then dose setting is prevented after the last dose, but remaining drug remains visible through the window inviting users to try to extricate it

Engineering Contradiction:
Improvedose controlVSAvoidvisual indication of remaining drug
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The cap is removed from the housing after the last dose is delivered, taking out the visual window that displays remaining drug. By removing the cap that would allow viewing through the window, the temptation to extract remaining drug is eliminated, while the lock-out feature continues to prevent dose setting.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2381988B1Medication delivery device
Publication Date: 2020.01.22 SANOFI AVENTIS DEUT GMBH
  • EP2381988B1 patent drawingFigure 1
  • EP2381988B1 patent drawingFigure 2~4

AI summary

A medication delivery device comprises a housing (1), a cap (2) configured to be attached to the housing (1) and a locking means (16, 17) configured to lock the cap (2). In a first state the cap (2) is detachable and in a second state the locking means (16, 17) locks the cap (2) if the cap (2) is attached.