High-Concentration Urea Skin Conditioning Composition
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Solution Overview
Problem
High concentrations of urea in cosmetic compositions for skin care are prone to hydrolysis, leading to pH increase and skin irritation, and tend to crystallize at low temperatures, reducing efficacy and causing aesthetic issues like skin whitening.
Innovation Solution
A water-based skin conditioning composition with a carrier system containing urea, amino acids, and triacetin or triethyl citrate, maintained at a pH between 4.0 and 6.0, which stabilizes urea and prevents crystallization, allowing for effective humectant properties and skin desquamation without irritation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high concentrations of urea (20-40% by weight) are used in water-based compositions for skin care, then the humectant properties and skin conditioning efficacy are improved, but the pH increases due to hydrolysis leading to skin irritation
Solution Approach 1:
The patent introduces amino acids as intermediary substances that buffer the pH increase caused by urea hydrolysis. The amino acids act as a mediator between the high concentration urea and the skin, preventing direct contact with highly alkaline conditions while maintaining the humectant benefits of urea.
Solution Approach 2:
The patent changes the chemical composition parameters by adding specific amino acids (glycine, alanine, valine, leucine, isoleucine, serine, threonine, cysteine, methionine, aspartic acid, glutamic acid, lysine, arginine, histidine, proline, tyrosine, phenylalanine, tryptophan) to alter the pH buffer capacity of the system, enabling high urea concentration without excessive pH increase.
2Reliability
If high concentrations of urea are used in cosmetic compositions, then the skin conditioning and desquamation effects are enhanced, but urea crystallizes at low temperatures reducing efficacy
Solution Approach 1:
The patent changes the physical state parameters by introducing amino acids that form molecular complexes with urea, lowering the crystallization temperature and preventing urea from crystallizing at typical storage temperatures, thus maintaining solution stability.
3Reliability
If high concentrations of urea are used for skin care, then the humectant properties are improved, but skin whitening occurs which is aesthetically unpleasant
Solution Approach 1:
The patent modifies the concentration parameters and composition by adding amino acids that modulate the interaction between urea and skin proteins, preventing the denaturation and aggregation that causes whitening while preserving the humectant effect.
4Productivity
If high concentrations of urea are used in water-based compositions, then the skin swelling and desquamation are promoted, but the composition becomes unstable and unsuitable for long-term use
Solution Approach 1:
The patent introduces amino acids as stabilizing intermediaries that prevent urea degradation and maintain pH stability over time, enabling long-term storage of high concentration urea compositions without loss of efficacy or development of irritating properties.
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 composition maintains stability and efficacy of urea, preventing pH increase and crystallization, thus enhancing skin moisture retention and desquamation while avoiding skin irritation and whitening, making it suitable for long-term use.
Implementation Method 1
One challenge relates to the tendency of urea to undergo a continuous hydrolysis reaction that leads to pH increase
Implementation Method 2
Yet another challenge is the tendency of urea to crystalize at high concentrations and at low temperature over time
Data Source
AI summary
A method for improving the efficacy of a skin care active includes applying, in any order, a first composition that includes a skin conditioning composition in carrier system having a water phase having: urea or a derivative thereof, present in an amount from about 20% to about 40%, by weight, based on the weight of the composition; at least one amino acid; at least one of triacetin or triethyl citrate; and, optionally, a buffer system having a pH in a range from about 4.0 to about 6.0, wherein the pH is less than about 7; and a second composition that includes a complementary composition including one or more skin actives not present in the skin conditioning composition. The complementary composition is a leave on or rinse of skin peel composition including at least a hydroxy acid. The compositions may be provided as an article of manufacture with separately contained compositions.