Pharmaceutical Closure Assembly for Low-Temperature Seal Integrity
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Solution Overview
Problem
Existing pharmaceutical container closures made of synthetic rubbers fail to maintain seal integrity at low temperatures due to reduced elasticity, leading to potential contamination and loss of efficacy for biological materials stored at temperatures below the glass transition temperature of conventional elastomers.
Innovation Solution
A sealed pharmaceutical container design featuring a flange with a conical upper surface and precise positioning of the stopper's sealing surface to ensure continuous contact, combined with a crimping process that maintains a residual nominal strain of less than or equal to 8%, thereby maintaining helium leakage rates below 1.4×10−6 cm³/s at temperatures up to −80°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional elastomer closures are used, then high permeation resistance and elasticity are achieved at room temperature, but seal integrity is lost at low temperatures below the glass transition temperature
Solution Approach 1:
The patent changes the material parameter by selecting elastomers with glass transition temperatures below the minimum storage temperature (Tg < −100°C), ensuring the closure material remains elastic and flexible at ultra-low storage temperatures where conventional elastomers would become rigid and fail to maintain seal integrity
Solution Approach 2:
The patent employs composite material selection by combining specific elastomer materials (such as fluoroelastomers or silicones) that exhibit both low glass transition temperatures and high elasticity, creating a closure material that maintains sealing performance across extreme temperature ranges from −196°C to +40°C
2Reliability
If the sealing surface outer peripheral edge is positioned at or radially inward of the flange outer peripheral edge, then seal integrity is maintained at low temperatures, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-positioning the sealing surface outer peripheral edge at or radially inward of the flange outer peripheral edge during the molding process, ensuring that the sealing geometry is established correctly before assembly, which maintains seal integrity at low temperatures while managing manufacturing precision requirements through design-stage positioning
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 design ensures effective seal integrity at low temperatures by maintaining a contact area of greater than 10% of the total surface area, reducing the probability of seal breakage and contamination, while allowing for simpler and more efficient crimping processes.
Implementation Method 1
Closures are typically made of synthetic rubbers and other elastomers. Such materials beneficially have high permeation resistance and elasticity to facilitate insertion into the container to seal the container's interior.
Implementation Method 2
a crimping cap used to secure the closure to the container
Data Source
AI summary
A sealed pharmaceutical container comprises a shoulder, a neck extending from the shoulder, and a flange extending from the neck. The flange comprises an outer surface extending from the underside surface and a contact surface extending between the outer surface and an inner surface defining an opening in the sealed pharmaceutical container. The contact surface comprises an outer peripheral edge disposed proximate to the outer surface of the flange. The sealed pharmaceutical container comprises a sealing assembly comprising a stopper extending over the contact surface of the flange and covering the opening, and a cap securing the stopper to the flange. The stopper comprises a sealing surface that is secured in contact with the contact surface of the flange to form a seal between the flange and the stopper. An outer peripheral edge of the sealing surface is disposed at or radially inward of the outer peripheral edge.