Stable Ascorbic Acid Compositions Using Reducing Sugars

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Solution Overview

Problem

L-ascorbic acid solutions are unstable due to its chemical properties, leading to degradation and reduced efficacy in pharmaceutical and cosmetic products, with existing stabilization methods being ineffective or costly.

Innovation Solution

Formulating aqueous compositions containing vitamin C, a reducing sugar, and surfactants, which stabilize vitamin C at pH levels of 2-5, enhancing its absorption through the skin and extending shelf life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If ascorbic acid is used in aqueous solution at higher pH levels, then solubility is improved, but chemical stability deteriorates due to formation of unstable ascorbate anion

Engineering Contradiction:
ImprovesolubilityVSAvoidchemical stability
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by lowering the pH level of the aqueous solution to below 5.0 (preferably 2.0-4.0), which shifts the chemical equilibrium to favor the stable protonated ascorbic acid form over the unstable ascorbate anion, thereby resolving the contradiction between solubility and chemical stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces buffering agents as intermediary substances that mediate between the need for solubility and chemical stability. These buffers maintain the pH within the optimal range (2.0-5.0), allowing ascorbic acid to remain stable while still achieving adequate solubility in the aqueous solution

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If ascorbic acid is stabilized using conventional methods (alkaline earth metal salts, ammonium salts, sulfite acid salts), then some stability is achieved, but the acid itself remains unstable and product costs increase

Engineering Contradiction:
Improveascorbic acid stabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the need for expensive stabilizing agents (alkaline earth metal salts, ammonium salts, sulfite acid salts) by focusing on pH control as the primary stabilization mechanism. This removes unnecessary components and reduces manufacturing costs while maintaining ascorbic acid stability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the pH parameter to below 5.0, which fundamentally alters the stability profile of ascorbic acid without requiring additional expensive stabilizing agents, thereby resolving the contradiction between achieving stability and controlling manufacturing costs

Inventive Principle:
Principle #35Parameter changes

3Duration of action of stationary object

If ascorbic acid solutions are formulated with conventional stabilizers, then some shelf life is extended, but product complexity and storage requirements increase

Engineering Contradiction:
Improveshelf lifeVSAvoidproduct formulation complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent removes complex stabilizing systems and multiple additives by relying on simple pH control (below 5.0) and the use of reducing sugars. This simplifies the formulation while extending shelf life, resolving the contradiction between shelf life extension and product complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the pH parameter and introduces reducing sugars as simple, effective stabilizers that extend shelf life without adding formulation complexity. This approach achieves long shelf life (years) with a simple, clean formulation

Inventive Principle:
Principle #35Parameter changes

4Reliability

If ascorbic acid is used in topical products, then therapeutic benefits are provided, but percutaneous absorption is limited due to instability and degradation

Engineering Contradiction:
Improvetherapeutic efficacyVSAvoidpercutaneous absorption barrier
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by stabilizing ascorbic acid in the formulation before application to the skin. By controlling pH below 5.0 and adding reducing sugars, the ascorbic acid remains stable and intact until it reaches the skin, preventing degradation that would otherwise block absorption and reduce therapeutic efficacy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the pH parameter to below 5.0 and introduces reducing sugars, which together create a stable formulation that enhances percutaneous absorption. This resolves the contradiction between maintaining therapeutic efficacy and overcoming the absorption barrier

Inventive Principle:
Principle #35Parameter changes

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 stable compositions maintain vitamin C's effectiveness, increasing its percutaneous absorption and shelf life, and allowing for previously unattainable product forms, such as stable aqueous solutions at lower pH levels, while reducing costs and storage complexities.

Implementation Method 1

L-ascorbic acid is chemically defined as an alpha-ketolactone... Ascorbic acid is moderately strong reducing agent... oxidative degeneration likely promotes instability due to the ascorbate anion's propensity to act as a reductant

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

the inclusion of surfactant in stable vitamin C solutions has been found to increase the percutaneous absorption of vitamin C in skin

Methodology Applied
Scientific EffectSurfactant: Surfactant

Data Source

PatentEP1940816A2Stable ascorbic acid compositions
Publication Date: 2008.07.09 OMP

AI summary

Compositions include vitamin C, water and a reducing sugar, result in increased stability of vitamin C. Further the addition of alcohol to aqueous vitamin C compositions increased the stability of vitamin C. Moreover, aqueous vitamin C compositions having surfactant included therein enhance the absorption of vitamin C into skin. Methods of using the stable vitamin C compositions are also described.