Vial Closure System with Obtuse Plug Angle
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Solution Overview
Problem
Existing vial closure systems face challenges in achieving a sterile seal, leading to difficulties in maintaining the sterility of the closure area, and they often result in loss of contents due to residual liquid trapping, especially when using a hollow needle for filling and sealing.
Innovation Solution
A closure system comprising an elastomer closure part, a resilient plastics clamp part, and a cover part that forms a sealing ridge to enhance the seal between the closure and the vial, along with a plug part design that minimizes liquid trapping by altering the internal angle to reduce capillary effects, allowing for heat sealing of the puncture hole using a laser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a hollow needle is used to fill the vial through the closure part, then the vial can be filled, but residual liquid is trapped in the puncture hole causing content loss
Solution Approach 1:
The internal angle of the plug part is changed from an acute angle to an obtuse angle (greater than 90 degrees), which alters the capillary effects and allows complete drainage of liquid from the puncture hole, eliminating content loss while maintaining efficient filling
2Ease of operation
If a clamp part with central aperture is used to expose the closure part, then the closure part is accessible, but achieving a sterile seal is difficult requiring user sanitization
Solution Approach 1:
The cover part is pre-assembled with the clamp part to form a sterile enclosure before use. The sealing ridge is already in position to create a sterile barrier, eliminating the need for user sanitization while maintaining accessibility to the closure part when needed
3Ease of manufacture
If the plug part has an acute internal angle, then it is easy to manufacture, but liquid is trapped due to capillary action
Solution Approach 1:
The internal angle parameter of the plug part is modified from acute to obtuse (greater than 90 degrees), which changes the capillary action characteristics and allows complete liquid drainage while remaining simple to manufacture using standard molding techniques
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
The system provides an improved sterile seal, reduces content loss by effectively sealing the vial after filling, and facilitates easy handling and processing in a sterile environment, minimizing the need for pre-use sanitization and ensuring efficient removal of contents.
Implementation Method 1
a lower surface of the cover part facing the upper surface of the closure part when so engaged has a sealing ridge projecting therefrom to a sealing edge that follows a closed perimeter, so that when the cover part is engaged with the clamp part and/or the vial the sealing edge engages with the closure part to form an enclosure with the closure part
Implementation Method 2
the needle is then withdrawn, and the small residual puncture hole may then be sealed by heat sealing, e.g. using a focussed laser beam
Implementation Method 3
an interior-facing surface which is exposed to the interior of the vial and which when the closure is in place encloses an angle of greater than 90° with the interior surface of the vial neck immediately below the plug part... This results in the problem that due to capillary action and/or surface tension liquid content becomes trapped in this acute angle
Data Source
AI summary
A closure system for a pharmaceutical vial, comprising an elastomer closure part, a clamp part which holds the closure part in engagement with the mouth of the vial, and a cover part which engages with the clamp part. The interior of the closure part is profiled to minimize retention of residual liquid therein.