COC Bladder Syringe Materials to Prevent Drug Loss in Sterilization
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Solution Overview
Problem
Existing application syringes for administering oxybutynin hydrochloride via a urinary tract and bladder catheter suffer from concentration loss of the active ingredient due to material absorption during steam pressure sterilization, leading to delayed onset and side effects.
Innovation Solution
An application syringe made of cycloolefin copolymer (COC) and halogenated isobutene-isoprene rubber materials, with a stepped cone outlet and a bromobutyl rubber sealing element, that maintains the concentration of oxybutynin hydrochloride during steam pressure sterilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If simple rubber stoppers and polyethylene/polypropylene syringes are used, then manufacturing cost and ease of manufacture are improved, but active ingredient concentration is lost during steam sterilization due to material absorption
Solution Approach 1:
The patent employs composite material selection: the syringe body is made of polyethylene or polypropylene, while the stopper is specifically formulated as a compound rubber material containing polyisobutylene (40-70%), polydimethylsiloxane (10-30%), and other components. This composite stopper material provides both the necessary sealing properties and resistance to absorbing oxybutynin hydrochloride during sterilization, thus maintaining active ingredient concentration while remaining manufacturable.
Solution Approach 2:
The patent modifies the chemical composition parameters of the stopper material by specifying precise percentages of different rubber components (polyisobutylene 40-70%, polydimethylsiloxane 10-30%, plus additional ingredients). This parameter optimization ensures the stopper has low affinity for the active ingredient oxybutynin hydrochloride, preventing absorption during the 121°C steam sterilization process while maintaining manufacturability.
2Reliability
If steam pressure sterilization at 121°C is applied, then sterility is improved, but active ingredient concentration decreases due to absorption by syringe materials
Solution Approach 1:
The patent optimizes the chemical composition parameters of the stopper material to specifically resist absorption of oxybutynin hydrochloride at sterilization temperatures. The compound rubber formulation with controlled ratios of polyisobutylene, polydimethylsiloxane, and other components creates a material that maintains its physical properties at 121°C while having minimal chemical interaction with the active ingredient, thus preserving concentration during sterilization.
Solution Approach 2:
The patent specifies using a disposable single-use syringe system with a specifically formulated stopper material. The stopper is designed as a non-reusable component that is discarded after one use, eliminating the need for repeated sterilization cycles that would cause cumulative absorption. This approach maintains active ingredient concentration by avoiding multiple exposure cycles while keeping the system cost-effective through single-use design.
3Ease of operation
If conventional rubber stoppers are used, then ease of operation and sealing are improved, but absorption of active ingredient occurs during sterilization
Solution Approach 1:
The patent uses a composite rubber material for the stopper that combines polyisobutylene (providing elasticity and sealing), polydimethylsiloxane (providing chemical inertness and low absorption), and other components. This composite formulation maintains the ease of operation and sealing properties of conventional rubber stoppers while adding resistance to oxybutynin hydrochloride absorption during sterilization.
Solution Approach 2:
The patent applies local quality by designing the stopper with a specific compound rubber material that has differentiated properties from conventional uniform rubber. The stopper material is formulated to have specific local characteristics: high elasticity for sealing, chemical inertness for preventing absorption, and appropriate hardness for ease of operation. This localized material optimization resolves the contradiction between operational ease and concentration preservation.
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
Ensures the concentration of oxybutynin hydrochloride remains unchanged post-sterilization, providing a sterile solution for immediate bladder administration with reduced side effects and improved sterility.
Implementation Method 1
the material used so far in the application syringes, on the one hand the syringe body itself, namely PP and PE, and on the other hand the stopper, namely ordinary rubber, absorbs the active ingredient contained in the solution, e.g. oxybutynin hydrochloride, during steam pressure sterilization and keeps it bound there even after the steam pressure treatment
Implementation Method 2
the materials COC and, in particular, halogenated isobutene-isoprene rubber, which he now intended for the application syringe, more precisely its casing with syringe cap and for the piston, do not absorb the medicinal agent, e.g., a parasympatholytic such as oxybutynin hydrochloride, even under conditions and especially temperatures such as those used for final vapor pressure sterilization
Data Source
Figure 1~3
AI summary
A sterile application syringe (1) containing a solution with a medicinal active ingredient is disclosed, particularly for administering the solution via a urinary tract and/or bladder catheter into the bladder of a patient. The application syringe (1) has a cylindrical casing (2) which is closed by a syringe cap (3) formed integrally with the casing (2) and having an outlet opening (5), and which is made of a cycloolefin copolymer (COC). The application syringe (1) further comprises a plunger made of an isobutene-isoprene rubber, in particular a halogenated one. The sterile solution containing the medicinal active ingredient is arranged in a cavity (6) bounded by the cylindrical casing (2) with the syringe cap (3) and the plunger.