Sealed-Heating Reactive NOx Assay for Nitroso Compound Control

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Solution Overview

Problem

Existing methods are inadequate for quantifying reactive NOx sources that contribute to the generation of nitroso compounds in pharmaceutical formulations, and there is a need to suppress the formation of these compounds, which are potentially carcinogenic.

Innovation Solution

A method involving contacting a sample with an amine source under sealed conditions and heating to generate nitroso compounds, followed by quantification using LC-MS/MS, focusing on secondary, tertiary, or quaternary amines to identify reactive NOx, and formulating with additives that suppress nitroso compound generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If all individual NOx sources are identified and controlled in formulations, then nitroso compound generation can be suppressed, but the complexity of formulation development and analysis becomes unmanageable

Engineering Contradiction:
Improvenitroso compound generationVSAvoidformulation development complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines multiple individual NOx source measurements into a single reactive NOx measurement using a diazotization reaction. Instead of identifying and controlling each NOx source separately (nitrite, nitrate, nitrosyl compounds, etc.), the invention merges their effects by reacting all NOx sources with a primary amine to form nitroso compounds, which are then quantified as total reactive NOx. This approach maintains effectiveness in suppressing nitroso compound generation while dramatically reducing formulation development complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal measurement method that quantifies all reactive NOx sources through a single assay. The diazotization reaction with primary amine serves as a multi-functional probe that reacts with various NOx sources (nitrite, nitrate, nitrosyl compounds) to produce measurable nitroso compounds. This universal approach eliminates the need for multiple separate identification and control methods for different NOx sources.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If reactive NOx is quantified by identifying and measuring all individual NOx sources, then complete control of nitroso compound generation is achieved, but the measurement process becomes impractical and overly complex

Engineering Contradiction:
Improvenitroso compound generation controlVSAvoidmeasurement practicality
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent merges the measurement of multiple individual NOx sources into a single reactive NOx quantification assay. By using a primary amine to react with all NOx sources simultaneously through diazotization, the method combines what would otherwise require multiple separate measurements into one practical operation. This maintains measurement precision for controlling nitroso compound generation while dramatically improving ease of operation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a primary amine as an intermediary substance that mediates the measurement of reactive NOx. The primary amine reacts with various NOx sources to form nitroso compounds, serving as a universal mediator that converts diverse NOx species into a single measurable form. This intermediary approach simplifies the measurement process while maintaining accuracy in quantifying nitroso compound generation potential.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method effectively quantifies reactive NOx and suppresses nitroso compound formation, ensuring pharmaceutical formulations meet acceptable safety limits, thereby reducing carcinogenic risks.

Implementation Method 1

nitroso compound is an organic compound with a nitroso group, and nitrosamine is a type of nitroso compound generated by nitrosation of amines (substitution of the hydrogen on the amine nitrogen with a nitroso group) with an NOx source such as nitrous acid

Methodology Applied
Scientific EffectNitrosation: Chemical Bonding

Data Source

PatentEP4600641A1Method for quantifying reactive nox, and formulation for suppressing generation of nitroso compounds
Publication Date: 2025.08.13 SAWAI PHARMA
  • EP4600641A1 patent drawingFigure 1
  • EP4600641A1 patent drawingFigure 2
  • EP4600641A1 patent drawingFigure 3

AI summary

An embodiment of the present invention provides a method for quantifying reactive NOx which is a source of NOx that may be involved in the generation of nitroso compounds. Alternatively, an embodiment of the present invention provides a formulation that suppresses the generation of a nitroso compound, designed based on a method for quantifying reactive NOx that may be involved in the generation of the nitroso compounds. In one embodiment, a method for quantifying reactive NOx includes adding an amine source to a sample to generate a nitroso compound. In one embodiment, nitroso compounds may be generated by heating under a sealed condition.