Polyvinylpyrrolidone Stabilization Against Peroxide Formation

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Solution Overview

Problem

Current methods for stabilizing polyvinylpyrrolidones against peroxide formation are either ineffective in the long term, costly, or pose health risks due to the use of antioxidants, heavy metals, or enzymes, and existing solutions do not adequately prevent peroxide buildup during storage and use in pharmaceutical preparations.

Innovation Solution

Treating polyvinylpyrrolidones with sulfur dioxide or sulfurous acid followed by a free-radical scavenger, such as ascorbic acid, to stabilize the polymers against peroxide formation, which can be done during polymerization and subsequent drying processes, allowing for effective stabilization without residual stabilizers in the final product.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polyvinylpyrrolidones are stored in oxygen-impermeable packages with oxygen scavengers, then peroxide formation is prevented, but the method is costly and complex

Engineering Contradiction:

Improveperoxide preventionVSAvoidpackaging complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by treating the polyvinylpyrrolidone with sulfur dioxide or sulfurous acid and a free-radical scavenger before storage, during polymerization, or during drying. This pre-treatment stabilizes the polymer against peroxide formation, eliminating the need for complex oxygen scavenging systems during storage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts the stabilization function from the storage phase and moves it to the polymerization or drying phase. By incorporating the stabilizing treatment early in the process, the complex oxygen scavenging packaging system becomes unnecessary.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If phenolic antioxidants are used to prevent oxidative processes, then peroxide formation is reduced, but biodegradability is deficient

Engineering Contradiction:

Improveoxidation preventionVSAvoidbiodegradability issue

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical parameters by using sulfur dioxide or sulfurous acid combined with free-radical scavengers instead of phenolic antioxidants. This substitution maintains oxidation prevention while avoiding the biodegradability problems associated with phenolic compounds.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If heavy metals or enzymes are used to cleave peroxides, then peroxide content is reduced, but health risks arise from accumulation or stability issues

Engineering Contradiction:

Improveperoxide reductionVSAvoidhealth risks

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs sulfur dioxide or sulfurous acid combined with free-radical scavengers as temporary stabilizing agents that perform their function during processing and storage, then degrade into harmless substances. This replaces persistent heavy metals and enzymes with short-lived, safe stabilizing components.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Reliability

If polyvinylpyrrolidones are spray dried under nitrogen atmosphere, then peroxide formation is prevented, but manufacturing complexity and cost increase

Engineering Contradiction:

Improveperoxide preventionVSAvoiddrying process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary stabilization treatment during polymerization or drying with sulfur dioxide or sulfurous acid and free-radical scavengers. This pre-protection allows subsequent drying to proceed under normal atmospheric conditions without requiring complex nitrogen atmosphere control.

Inventive Principle:

Principle #10Preliminary 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

This method provides long-term stabilization against peroxide formation, even in oxygen-containing environments, without the use of harmful residues, making the stabilized polyvinylpyrrolidones suitable for pharmaceutical and cosmetic applications without allergic reactions or intolerances.

Implementation Method 1

treating the polyvinylpyrrolidones initially with sulfur dioxide, sulfurous acid or the alkali metal salts thereof

Methodology Applied

Scientific EffectChemical stabilization:

Implementation Method 2

subsequently with a free-radical scavenger

Methodology Applied

Scientific EffectFree-radical scavenging:

Implementation Method 3

The antioxidants employed are, for example, phenolic or bisphenolic compounds, preferably thioamide or thiourea derivatives

Methodology Applied

Scientific EffectAntioxidation: Oxidation

Data Source

PatentUS8524827B2Method for the stabilization of polyvinylpyrrolidones

Publication Date: 2013.09.03 BASF SE

AI summary

Method for stabilizing polyvinylpyrrolidones, which comprises treating the polyvinylpyrrolidones with sulfur dioxide, sulfurous acid or alkali metal sulfites and then with free-radical scavenger, and converting the solutions treated in this way into the powdered polyvinylpyrrolidones by drying.