Vegetable Oil Contrast Agent Stabilization via Sulfur Dioxide

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Solution Overview

Problem

Existing iodized fatty acid ethyl ester contrast agents, such as Lipiodol, suffer from stability issues due to the release of iodine over time, leading to discoloration and a rapid decrease in quality.

Innovation Solution

A contrast agent is developed by combining an iodinated unsaturated fatty acid ethyl ester derived from vegetable oil with a non-iodinated unsaturated fatty acid ethyl ester and sulfur dioxide (SO2), which enhances stability and prevents iodine release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If iodinated unsaturated fatty acid ethyl ester is used as contrast agent, then X-ray impermeability is improved, but stability deteriorates due to iodine release causing discoloration

Engineering Contradiction:

ImproveX-ray impermeabilityVSAvoidstability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

Sulfur dioxide is introduced as an intermediary substance that binds to free iodine through formation of a charge-transfer complex, preventing iodine from causing discoloration while maintaining the contrast agent's X-ray impermeability. This mediator approach resolves the contradiction by capturing the harmful iodine without removing the beneficial iodinated fatty acid ethyl ester.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The contrast agent is formulated as a composite system containing iodinated unsaturated fatty acid ethyl ester, non-iodinated unsaturated fatty acid ethyl ester, and sulfur dioxide. This composite structure allows the iodinated component to provide X-ray contrast while the sulfur dioxide component stabilizes the system by binding released iodine, thus achieving both high reliability and stability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If poppy seed oil is used to produce Lipiodol, then contrast agent quality is improved, but cost and supply stability deteriorate

Engineering Contradiction:

Improvecontrast agent qualityVSAvoidcost and supply stability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive poppy seed oil with cheaper, more readily available vegetable oils such as sunflower seed oil, soybean oil, or peanut oil. These alternative oils are abundant, inexpensive, and can be easily manufactured into contrast agents, thereby improving ease of manufacture while maintaining adequate contrast agent quality through the addition of sulfur dioxide for stabilization.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Duration of action of stationary object

If storage period is prolonged, then more time for medical use is available, but quality decreases due to iodine release and discoloration

Engineering Contradiction:

Improvestorage periodVSAvoidquality

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

Sulfur dioxide is added to the contrast agent formulation in advance to preemptively counteract iodine release. The sulfur dioxide forms a charge-transfer complex with any free iodine that may be released during storage, preventing discoloration and quality degradation. This preliminary protective action allows the contrast agent to maintain high quality throughout an extended storage period.

Inventive Principle:

Principle #9Preliminary anti-action

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 proposed solution achieves a highly stable contrast agent with X-ray impermeability similar to Lipiodol, using inexpensive and easily available vegetable oils, and maintains transparency over a considerable period without browning.

Implementation Method 1

it has been found that when a contrast agent is stabilized by sulfur dioxide, free iodine generated due to ultraviolet irradiation or heat is combined with sulfur dioxide to form a charge-transfer complex

Methodology Applied

Scientific EffectCharge-transfer complex formation:

Implementation Method 2

Lipiodol, a liver cancer contrast agent produced and sold by the global pharmaceutical Guerbet, is an iodized fatty acid ethyl ester of poppy seed oil, which is used for imaging tests

Methodology Applied

Scientific EffectX-ray absorption: Absorption (EM radiation)

Data Source

PatentUS12201701B2Vegetable oil-derived contrast agent with high stability and preparation method thereof

Publication Date: 2025.01.21 ENGAIN CO LTD

AI summary

Proposed are a contrast agent containing an iodinated unsaturated fatty acid ethyl ester derived from vegetable oil, a non-iodinated unsaturated fatty acid ethyl ester, and sulfur dioxide (SO2), and a production method thereof. The contrast agent having a similar contrast effect is synthesized using vegetable oil as a substitute for poppy seed oil, which is unstable in terms of supply and is expensive. In addition, the long-term stability problem of an iodine-based contrast agent is solved by adding a non-iodinated unsaturated fatty acid ethyl ester and sulfur dioxide.