Dibenzoylmethane UVA Sunscreen Stability in Cinnamic Acid Formulations
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Solution Overview
Problem
Dibenzoylmethane UVA sunscreens are unstable when combined with cinnamic acid UVB sunscreens in personal care compositions, leading to rapid degradation under sunlight exposure, compromising long-term UV protection.
Innovation Solution
A photo-protective personal care composition is developed where the UVA sunscreen of the dibenzoylmethane class is entrapped in a matrix of hydrophobically modified silica and amino functionalized silicone, while the UVB sunscreen of the cinnamate class is entrapped in a gel comprising silicone elastomer and volatile silicone, maintaining stability and efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dibenzoylmethane UVA sunscreen and cinnamic acid UVB sunscreen are combined in personal care compositions, then broad-spectrum UV protection is achieved, but the UVA sunscreen degrades rapidly under sunlight exposure
Solution Approach 1:
The patent divides the sunscreen composition into two separate phases: an aqueous phase containing the UVA sunscreen (dibenzoylmethane) and an oily phase containing the UVB sunscreen (cinnamic acid). This segmentation prevents direct interaction between the two sunscreen agents, thereby maintaining the stability of the UVA component while achieving broad-spectrum protection through the combination of both phases.
Solution Approach 2:
The patent introduces an intermediary emulsion system that acts as a barrier between the UVA and UVB sunscreen agents. The emulsion comprises aqueous phase, oily phase, and emulsifying phase, which mediates the interaction between the two sunscreen components and prevents the degradation of UVA sunscreen by cinnamic acid UVB agents.
2Stability of the object's composition
If external molecules like Octocrylene are added to improve UVA sunscreen stability, then photostability is enhanced, but formulation complexity and cost increase
Solution Approach 1:
The patent extracts the problematic interaction between UVA and UVB sunscreen agents by separating them into different phases. Instead of adding external stabilizing molecules like Octocrylene to the entire formulation, the invention removes the source of instability by physically separating the cinnamic acid UVB agents from the dibenzoylmethane UVA agents, thereby simplifying the formulation approach.
Solution Approach 2:
The patent applies local quality by creating distinct micro-environments for each sunscreen agent. The UVA sunscreen resides in the aqueous phase with its own stabilizing conditions, while the UVB sunscreen is contained in the oily phase. This localized separation allows each component to maintain its optimal stability without requiring additional stabilizing agents throughout the entire formulation.
3Adaptability or versatility
If UVA and UVB sunscreens are incorporated together, then protection over entire UV range is provided, but UVA sunscreen degrades in half hour to two hours under sunlight
Solution Approach 1:
The patent segments the sunscreen formulation into aqueous and oily phases, with UVA sunscreen in the aqueous phase and UVB sunscreen in the oily phase. This physical segmentation prevents the rapid degradation that occurs when these agents are mixed, thereby extending the duration of UVA sunscreen activity from half hour to two hours to long-term protection while maintaining broad-spectrum coverage.
Solution Approach 2:
The emulsion system acts as an intermediary that allows both UVA and UVB protection to coexist without the harmful interactions that limit duration. The emulsion structure maintains the separation of the two sunscreen agents while ensuring both are delivered to the skin, enabling prolonged protection duration without sacrificing the broad UV range coverage.
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 provides high SPF and UVAPF values, ensuring long-term UVA protection and affordability by using conventional, widely available ingredients, thereby overcoming the instability issues of prior art compositions.
Implementation Method 1
both UV-A and UV-B sunscreens are usually incorporated in photo-protective compositions so as to provide protection over the entire range of UV radiation
Implementation Method 2
both UV-A and UV-B sunscreens are usually incorporated in photo-protective compositions so as to provide protection over the entire range of UV radiation
Implementation Method 3
a gel comprising silicone elastomer and a volatile silicone wherein a UVB sunscreen of the cinnamate class is entrapped
Data Source
AI summary
The invention relates to a photo-protective personal care composition, especially to one that provides enhanced stability of a UVA sunscreen of the dibenzoylmethane class when a UVB sunscreen of the cinnamic acid class is also present. This has been achieved by entrapping the UVA sunscreen in a matrix comprising a specific silica and a specific silicone and combining this with a UVB sunscreen being entrapped in a gel made of a silicone elastomer and a volatile silicone.