Syringe Inner Lubricant Coating with a Circumferential Capillary Gap
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Solution Overview
Problem
Existing methods for coating pharmaceutical containers, such as syringes, struggle to achieve a homogeneous and uniform coating layer, leading to abrupt changes in gliding force and potential contamination during the administration of pharmaceutical compositions, while also being difficult to scale for mass production.
Innovation Solution
A method involving a capillary bridge technique is employed, where a circumferential gap is maintained between the application body and the inner surface of the container, allowing the coating composition to form a capillary bridge, resulting in a uniform coating thickness and reduced accumulation, thereby enhancing gliding properties and reducing contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spray coating method is used, then coating can be applied to the container, but the coating layer is not homogenous and gliding force changes abruptly
Solution Approach 1:
The patent introduces an intermediary liquid coating composition that forms a capillary bridge between the application body and container inner surface. This liquid intermediary enables uniform coating transfer without direct contact, resolving the contradiction between coating precision and operational smoothness by mediating the coating deposition process through capillary action rather than spray or direct contact methods
Solution Approach 2:
The patent changes the physical parameters of the coating process by using a liquid coating composition with specific viscosity and surface tension properties that enable capillary bridge formation. By controlling the liquid film thickness and capillary pressure, the system achieves uniform coating deposition while maintaining smooth stopper movement, thus resolving the contradiction through parameter optimization
2Quantity of substance
If press-fit coating process is used, then application body contacts inner surface directly, but coating composition accumulates and creates inhomogeneities
Solution Approach 1:
The patent extracts the harmful direct contact between the application body and container inner surface by introducing a circumferential gap. The coating composition is transferred through the capillary bridge without the application body touching the surface, preventing accumulation and inhomogeneities while ensuring uniform distribution of the coating substance
Solution Approach 2:
The patent replaces the mechanical press-fit contact system with a capillary bridge-based liquid transfer system. Instead of relying on mechanical contact to deposit coating, the system uses capillary pressure and surface tension to control coating composition distribution, eliminating mechanical accumulation issues and achieving homogeneous coating
3Manufacturing precision
If circumferential gap is introduced for capillary bridge, then coating uniformity improves, but process complexity increases
Solution Approach 1:
The patent employs self-service by allowing the coating composition to automatically form a capillary bridge and deposit uniformly through its own surface tension and capillary pressure properties. The system utilizes the inherent physical properties of the liquid coating material to achieve uniform deposition without requiring complex external control mechanisms, thus improving coating precision while minimizing process complexity
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 capillary bridge technique achieves a uniform coating thickness with low variability, improving the smooth movement of stoppers and reducing contamination risks, particularly in pre-filled syringes, while being suitable for large-scale production.
Implementation Method 1
the coating composition, which is applied to the application body, to touch or contact at least a part of the inner surface of the wall and the application body, thereby bridging the gap between the application body and the inner surface, forming a so-called capillary bridge
Data Source
Figure 1~2D
Figure 3A~3B
Figure 4A~4B
AI summary
This disclosure relates to a method of making a coated container, e.g. a syringe. This disclosure particularly relates to method of making a container with a lubricant coating on an inner surface. This disclosure also relates to coated containers.