Horizontal Lyophilization Syringe Assembly for Uniform Drying
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Solution Overview
Problem
Conventional lyophilization processes using cylindrical syringes are inefficient due to low surface-to-volume ratios, leading to prolonged lyophilization cycles and non-uniform heating, which results in incomplete drying and increased storage and transportation costs for temperature-sensitive pharmaceuticals.
Innovation Solution
A lyophilization assembly and method utilizing a thermal block with heat-conductive material and a syringe design featuring a horizontal orientation and increased surface area, combined with a stopper mechanism for venting and sealing, to enhance heat transfer and prevent contamination during the lyophilization and storage of pharmaceuticals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional cylindrical syringes are used for lyophilization, then the device structure is simple, but the surface-to-volume ratio is low resulting in prolonged lyophilization cycles
Solution Approach 1:
The syringe is reoriented from a vertical cylindrical configuration to a horizontal configuration, changing the dimensional arrangement to increase the exposed surface area of the lyophilizable material. This horizontal orientation allows the material to spread along the syringe barrel, maximizing the surface area available for sublimation and significantly reducing the lyophilization cycle time.
2Manufacturing precision
If conventional lyophilization methods are used, then the process is simple, but heating is non-uniform causing incomplete drying
Solution Approach 1:
The horizontal orientation of the syringe creates different thermal zones along the barrel length, with the heat source applied locally at specific positions. This allows targeted heating of different sections of the lyophilizable material, ensuring uniform drying throughout the sample by adjusting the heat application position and duration for each zone.
3Loss of energy
If lyophilized pharmaceuticals are stored at ambient temperatures, then storage and transportation costs are reduced, but product stability may be compromised
Solution Approach 1:
The lyophilization process is performed in advance to create a stable, dried pharmaceutical product before storage and transportation. This preliminary action of complete lyophilization ensures that the product achieves long-term stability at ambient temperatures, eliminating the need for continuous refrigeration during storage and transport while maintaining product reliability.
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
This approach significantly reduces lyophilization cycle times, ensures uniform drying, and allows for the storage and transportation of pharmaceuticals at ambient temperatures, maintaining product stability and reducing logistical costs.
Implementation Method 1
utilizing a thermal block with heat-conductive material... to enhance heat transfer
Implementation Method 2
removing the ice via sublimation... the ice via sublimation
Implementation Method 3
stopper mechanism for venting and sealing... providing a passage through the stopper for venting gas from the syringe interior
Data Source
AI summary
Herein described is a syringe assembly configured for the in situ lyophilization of an initial liquid preparation into a lyophilized product as well as the subsequent sealing of the lyophilized product for storage and transport, user reconstitution of the lyophilized product, and dispensing of the lyophilized product in rehydrated form to a patient in a medical setting, all in the same syringe. The combination lyophilization and dispensing syringe assemblies of the present invention greatly enhance the efficiency of the lyophilization process and find particular utility in conjunction with the dedicated lyophilization apparatus and methods described in U.S. Pat. Nos. 11,536,512 and 11,723,870. In particularly preferred embodiments, the present invention provides for shortened lyophilization cycles in a syringe barrel optionally fitted with a sealing Luer lock cap at its distal end and a vented stopper at its proximal end. During lyophilization, gas may flow out of the syringe barrel and through the stopper. After lyophilization, the stopper slid to its sealed position, thereby forming an airtight syringe whose contents are insulated from surrounding atmosphere and potential contamination. During the life cycle of the filled syringe, from seal to storage to transport, the lyophilized material is never exposed to the atmosphere. In addition, at time of use, an elongate stem may be threaded into the stopper to form a dispensing plunger in which the stopper acts as a sealing piston element In this manner, the assembly of syringe barrel, stopper and elongated stem constitute a fully functioning syringe that may be used to rehydrate and dispense the medicament of interest.