Silicone Composition pH Stability After Gamma Irradiation

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Solution Overview

Problem

Conventional silicone-based materials used in biopharmaceutical applications undergo pH variation after gamma radiation, potentially forming acidic species that can be harmful when in contact with fluids, leading to a need for improved compositions that maintain a stable pH.

Innovation Solution

A silicone-based composition incorporating a silicone polymer and an acid neutralizer, such as a metal oxide or ion exchanger, which maintains a pH of at least 5 after irradiation, effectively neutralizing acidic species formed during gamma sterilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional silicone-based materials are used for biopharmaceutical applications, then the materials provide flexibility and chemical resistance, but the materials undergo pH variation after gamma radiation forming acidic species that can be harmful

Engineering Contradiction:
ImprovepH stability after irradiationVSAvoidacidic species formation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A basic inorganic material (metal oxide or ion exchanger) is introduced as an intermediary substance within the silicone composition to neutralize acidic species formed during gamma radiation. This intermediary component reacts with the harmful acidic byproducts, converting them into harmless substances and maintaining pH stability in the range of 5-7 after irradiation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite material system combining silicone polymer with basic inorganic materials (such as magnesium oxide, calcium oxide, or ion exchangers). This composite approach leverages the beneficial properties of both components: the flexibility and chemical resistance of silicone plus the pH-stabilizing and acid-neutralizing properties of the basic inorganic material.

Inventive Principle:
Principle #40Composite materials

2Reliability

If gamma radiation is used for sterilization of biopharmaceutical products, then sterilization is achieved, but pH variation occurs in conventional silicone materials

Engineering Contradiction:
Improvesterilization effectivenessVSAvoidpH composition stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The basic inorganic material is incorporated into the silicone composition before sterilization. This preliminary inclusion ensures that when gamma radiation occurs, the neutralizing agent is already in position to immediately counteract acidic species formation, preventing pH variation rather than correcting it afterward.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention converts the harmful effect of gamma radiation (acidic species formation and pH drop) into a beneficial outcome by incorporating basic inorganic materials that neutralize these acidic byproducts. The radiation-induced acidic species, which would normally be harmful, are transformed into harmless substances through neutralization, maintaining the composition's pH stability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 inclusion of acid neutralizers in the silicone-based composition ensures a stable pH of at least 5 after irradiation, enhancing the safety and performance of silicone articles by preventing pH drops and maintaining desirable properties like flexibility and chemical resistance.

Implementation Method 1

the acid neutralizer comprises a metal oxide, an ion exchanger or a combination thereof... effectively neutralizing acidic species formed during gamma sterilization

Methodology Applied
Scientific EffectAcid-base neutralization:

Implementation Method 2

the acid neutralizer comprises a metal oxide, an ion exchanger or a combination thereof

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Data Source

PatentEP3555213B1Silicone-based composition and article made therefrom
Publication Date: 2022.01.26 SAINT GOBAIN PERFORMANCE PLASTICS CORP
  • EP3555213B1 patent drawingFigure 1~2
  • EP3555213B1 patent drawingFigure 3~4
  • EP3555213B1 patent drawingFigure 5~6

AI summary

A silicone-based composition includes a silicone polymer and at least one acid neutralizer, wherein the silicone-based composition has a pH of at least about 5 after at least one dose of irradiation, when measured by a pH meter.