Iodixanol Dimerization Solvent System for Purity and Yield
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Solution Overview
Problem
The existing methods for producing iodixanol, a non-ionic X-ray contrast agent, are inefficient and costly due to high impurity levels and lengthy purification processes, particularly in the dimerization step, which requires multiple crystallizations and is time-consuming and equipment-intensive.
Innovation Solution
A dimerization process using a solvent mixture of 70-90 vol% 1-methoxy-2-propanol and 10-30 vol% water or methanol at a temperature range of 10-20°C with 0.8-2.0 ml solvent per g of 5-acetamido-N,N′-bis(2,3-dihydroxypropyl)-2,4,6-triiodo-isophthalamide and 0.30-0.40 mole equivalents of epichlorohydrin, reducing impurities and enhancing yield and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dimerization reaction is carried out in non-aqueous solvent 2-methoxyethanol, then the reaction can proceed, but the product contains large amounts of impurities requiring multiple crystallizations
Solution Approach 1:
The patent changes the solvent parameters from non-aqueous 2-methoxyethanol to an aqueous mixture of 1-methoxy-2-propanol and water or methanol. This parameter change in solvent composition fundamentally alters the reaction outcome, achieving high product purity (minimizing backpeaks to less than 2%) while eliminating the need for multiple crystallization steps, thus resolving the contradiction between product purity and process time
Solution Approach 2:
The patent uses a composite solvent system comprising 1-methoxy-2-propanol combined with water or methanol in specific ratios (70-90 vol% 1-methoxy-2-propanol and 10-30 vol% water or methanol). This composite solvent mixture provides synergistic effects that achieve both high conversion (40-60% of Compound A to iodixanol) and high purity, eliminating the time-consuming multiple crystallizations required when using single non-aqueous solvents
2Reliability
If multiple crystallizations are performed to achieve desired purity, then product purity is improved, but the process becomes time-consuming and equipment-intensive
Solution Approach 1:
By changing the solvent parameters to the specific aqueous mixture of 1-methoxy-2-propanol with water or methanol, the patent achieves high product purity in a single reaction step without requiring multiple crystallization cycles. This parameter change transforms the process from a multi-step purification sequence to a single-step high-yield reaction, significantly improving manufacturing efficiency while maintaining product quality
Solution Approach 2:
The patent takes out the need for multiple crystallization steps by using a solvent system that inherently produces high-purity product. The aqueous solvent mixture prevents impurity formation at the source, eliminating the extraction/purification bottleneck and enabling continuous manufacturing with higher productivity
3Ease of manufacture
If conventional dimerization methods are used, then the process is established, but the cost of the final formulated product is high
Solution Approach 1:
The patent changes the solvent parameters to use 1-methoxy-2-propanol with water or methanol, which are low-cost, easily accessible solvents. This parameter change reduces the cost of goods while maintaining high product purity and yield, directly addressing the high product cost issue of conventional methods without sacrificing manufacturing reliability
Solution Approach 2:
The patent employs cheap, readily available solvents (1-methoxy-2-propanol, water, or methanol) instead of expensive specialized solvents. This substitution of inexpensive solvent materials reduces the overall manufacturing cost while achieving the desired product quality, making the process economically viable for large-scale production
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
This process significantly reduces impurities, achieving high yields and economic feasibility by minimizing backpeaks to less than 2%, thus optimizing the manufacturing of iodixanol on an industrial scale.
Implementation Method 1
the dimerisation of 5-acetamido-N,N′-bis(2,3-dihydroxypropyl)-2,4,6-triiodo-isophthalamide with a solvent mixture comprising 1-methoxy-2-propanol and water or methanol
Data Source
AI summary
This invention relates to the synthesis of iodixanol (1,3-bis(acetamido)-N,N′-bis[3,5-bis(2,3-dihydroxypropylaminocarbonyl)-2,4,6-triiodophenyl]-2-hydroxypropane), more specifically to the dimerization of 5-acetamido-N,N′-bis(2,3-dihydroxypropyl)-2,4,6-triiodo-isophthalamide with a solvent mixture comprising 1-methoxy-2-propanol and water or methanol.