Lubricant Coating for Medical Injection Devices
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Solution Overview
Problem
Medical injection devices are not compatible with high-value biotech drugs, leading to degradation and aggregation due to interactions with traditional coatings, which compromise the integrity and safety of the pharmaceuticals over time, and fail to meet pharmacopeia norms for particle levels.
Innovation Solution
A lubricant coating comprising a bottom layer of cross-linked and non-cross-linked poly-(dimethylsiloxane), an intermediate oxidized layer, and a top non-cross-linked layer, applied using a specific plasma treatment process, to reduce particle generation and maintain gliding properties over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lubricant coating is applied to improve gliding properties, then the gliding force is reduced, but the coating may delaminate or break over time, compromising integrity
Solution Approach 1:
The coating is divided into three distinct layers with different compositions and functions: a bottom layer for adhesion to the container surface, an intermediate oxidized layer for stability and barrier properties, and a top non-cross-linked layer for low friction and gliding performance. This segmentation allows each layer to optimize its specific function while working together to solve the contradiction between gliding properties and coating integrity.
Solution Approach 2:
The invention uses a composite coating structure combining cross-linked and non-cross-linked poly(dimethylsiloxane) in different layers. The cross-linked intermediate layer provides mechanical stability and prevents delamination, while the non-cross-linked top layer maintains low friction. This composite approach resolves the contradiction by integrating materials with complementary properties.
2Ease of operation
If traditional coatings are used to enhance lubrication, then gliding properties are improved, but drug degradation and aggregation occur due to interactions with the coating
Solution Approach 1:
The coating structure is designed with local quality variations: the top layer consists of non-cross-linked poly(dimethylsiloxane) that provides low friction and minimal interaction with biotech drugs, while the intermediate oxidized layer and bottom cross-linked layer provide structural support and adhesion. This local differentiation allows the surface in contact with the drug to have benign properties while maintaining overall coating integrity and lubrication performance.
Solution Approach 2:
The invention changes the chemical and physical parameters of the coating layers, specifically using non-cross-linked poly(dimethylsiloxane) in the top layer with controlled thickness (at most 2 nm) and oxidation level in the intermediate layer. These parameter changes reduce drug-coating interactions that cause degradation while preserving the necessary lubrication properties for stopper gliding.
3Object-generated harmful factors
If a coating is applied to reduce particle generation, then particle levels decrease, but the coating complexity increases with multiple layers
Solution Approach 1:
The coating is segmented into three functional layers, each with specific thickness and composition requirements. The bottom layer (cross-linked poly(dimethylsiloxane)) provides adhesion, the intermediate layer (oxidized poly(dimethylsiloxane), 10-30 nm) provides stability and prevents particle generation, and the top layer (non-cross-linked poly(dimethylsiloxane), at most 2 nm) provides low friction. This segmentation reduces particle generation while maintaining manageable complexity through clear functional differentiation.
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 coating significantly reduces particle generation, maintains the integrity of biotech drugs, and ensures stable gliding performance for the duration of the injection device's shelf life, adhering to pharmacopeia standards and minimizing risks to patients.
Implementation Method 1
an intermediate layer consisting essentially of oxidized poly-(dimethylsiloxane)
Implementation Method 2
applied using a specific plasma treatment process
Implementation Method 3
a bottom layer in contact with the medical device surface of the container to be lubricated, comprising a mixture of cross-linked and non-cross-linked poly-(dimethylsiloxane)
Implementation Method 4
lubricant coating... to improve the lubrication of the stopper inside the container
Data Source
AI summary
The invention relates to a lubricant coating (5) for a medical injection device (1), comprising successively: —a bottom layer (50) in contact with the medical device surface (21) of the container to be lubricated, comprising a mixture of cross-linked and non-cross-linked poly-(dimethylsiloxane), —an intermediate layer (51) consisting essentially of oxidized poly-(dimethylsiloxane) and having a thickness comprised between 10 and 30 nm and, —a top layer (52) consisting essentially of non-cross-linked poly-(dimethylsiloxane) and having a thickness of at most 2 nm. The invention also relates to a medical injection device comprising such a lubricant coating, and a manufacturing process for said coating.