Flat-Bottom Polymer Vials for Lyophilization Heat Transfer
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Solution Overview
Problem
Existing glass vials used for pharmaceutical lyophilization face issues such as contamination, breakage, and non-uniform surface chemistry, while plastic vials suffer from gas permeability and leachables, making them unsuitable for lyophilization applications.
Innovation Solution
The development of polymer vials with a substantially flat bottom and a symmetrical sidewall, produced through injection stretch blow molding, which includes a PECVD water barrier coating, to enhance thermal efficiency and gas barrier properties, and a method using a mold with a flat base mold to ensure precise dimensional control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass vials are used for pharmaceutical lyophilization, then chemical inertness and surface uniformity are improved, but breakage risk and contamination from metal components increase
Solution Approach 1:
The invention changes the material parameter from glass to plastic (specifically polyolefin), fundamentally altering the physical and chemical properties to achieve both chemical inertness and breakage resistance. This material substitution resolves the contradiction by providing a non-breakable alternative that maintains chemical stability.
Solution Approach 2:
The invention uses composite construction with multiple plastic layers (e.g., polyolefin outer layer combined with other polymer layers) to achieve the desired balance of chemical inertness, gas barrier properties, and mechanical strength, eliminating the need for glass while maintaining reliability.
2Strength
If plastic vials are used to eliminate breakage, then strength and safety are improved, but gas permeability and leachables increase
Solution Approach 1:
The invention employs multi-layer composite plastic construction where specific layers (such as EVOH or PVDC barrier layers) are integrated between polyolefin layers to provide excellent gas and vapor barrier properties. This composite approach maintains breakage resistance while eliminating gas permeability issues.
Solution Approach 2:
The invention applies different material properties to different regions of the vial wall - the outer and inner layers use polyolefin for chemical inertness and strength, while intermediate layers use high-barrier materials specifically positioned to address gas permeability concerns. This localized material assignment resolves the contradiction effectively.
3Ease of manufacture
If conventional blow molding is used for plastic vials, then ease of manufacture is improved, but dimensional precision and thermal efficiency deteriorate
Solution Approach 1:
The invention replaces conventional extrusion blow molding with injection stretch blow molding technology, which uses injection molding mechanics to create preforms with precise dimensional control before stretching and forming. This substitution maintains ease of manufacture through automated processes while dramatically improving dimensional precision and thermal efficiency.
4Ease of manufacture
If domed base vials are manufactured, then ease of manufacture is improved, but thermal efficiency during lyophilization deteriorates
Solution Approach 1:
The invention inverts the conventional domed base design by implementing a substantially flat base. This inversion changes the thermal contact geometry from point/line contact (domed) to surface contact (flat), dramatically improving thermal efficiency during lyophilization while remaining compatible with automated manufacturing processes.
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 polymer vials provide improved thermal efficiency, reduced gas permeability, and consistent dimensions, ensuring stable storage and lyophilization of biologics without contamination, addressing the limitations of glass and plastic vials.
Implementation Method 1
The polymer vials provide improved thermal efficiency, reduced gas permeability, and consistent dimensions, ensuring stable storage and lyophilization of biologics without contamination
Implementation Method 2
polymer vials with substantially flat bottoms and injection stretch blow molding methods for making the same
Data Source
AI summary
Disclosed are polymer vials (110, 210) and injection stretch blow molding methods for making the same. A polymer vial has a base (112) having a base surface area and a sidewall (114) extending up from the base. The base and sidewall define an interior (116) configured to house product, the sidewall narrowing at an upper section of the vial to form a neck leading to an opening that provides access to the interior. The vial is optionally round and symmetrical about a central axis, a lower portion of the sidewall including a first surface that is outwardly curved along a first radius having an imaginary center positioned within the vial. The base is positioned below the first surface and is substantially flat such that at least 80% of the base surface area has a standing base surface occupying a single plane.