Structurally Diverse Sunscreen Particle Matrix for Stable UV Protection
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Solution Overview
Problem
Existing sunscreens face challenges in achieving stability, broad-spectrum efficacy, effective incorporation of active ingredients, cosmetic elegance, and resistance to water exposure, while avoiding undesirable aesthetic characteristics such as a white cast or greasiness.
Innovation Solution
Formulations comprising a matrix of structurally diverse photoprotective particles, including various types of primary particles and agglomerates, with specific size and composition distributions, to enhance UV protection and cosmetic appeal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high concentrations of metal oxide particles are used to achieve high SPF and broad-spectrum protection, then UV protection efficacy is improved, but the formulation becomes unstable and particles aggregate and settle
Solution Approach 1:
The patent divides the particle population into multiple size segments (nano particles 1-100 nm, micro particles 1-10 micrometers, and macro particles 10-100 micrometers) with different functions. Nano particles provide UV absorption, micro particles provide scattering, and macro particles provide structure and prevent settling. This segmentation allows high total particle concentration for SPF efficacy while distributing particles across size ranges that collectively maintain formulation stability.
Solution Approach 2:
The patent creates a composite particle system combining metal oxide particles (zinc oxide, titanium dioxide) with styrene acrylate copolymer particles. The polymer matrix binds the metal oxide particles together, preventing their aggregation and settling while maintaining their UV protective functions. This composite approach enables high particle loading without the instability issues that would result from using metal oxide particles alone.
2Reliability
If high particle loading is used to achieve effective UV protection, then sun protection factor is improved, but the product leaves a white cast and exhibits undesirable aesthetic characteristics
Solution Approach 1:
The patent assigns different optical properties to particles of different sizes within the formulation. Nano particles (1-100 nm) are optimized for UV absorption with minimal visible light interaction, micro particles (1-10 micrometers) provide scattering primarily in the UV range, and macro particles (10-100 micrometers) provide structural support. This local differentiation of particle functions allows high total particle loading for SPF efficacy while the specific size distribution minimizes white cast by reducing visible light scattering.
3Ease of operation
If complex formulations with multiple inactive ingredients are used to improve cosmetic elegance and stability, then product performance is improved, but the formulation complexity increases
Solution Approach 1:
The patent designs the styrene acrylate copolymer particles to perform multiple functions simultaneously: they bind metal oxide particles together (preventing aggregation), provide a cosmetically elegant base that improves spreadability and reduces greasiness, and contribute to formulation stability. This multi-functionality reduces the need for separate inactive ingredients, simplifying the overall formulation while maintaining cosmetic elegance and stability.
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 solution provides advanced UV protection with a high SPF, UVA/UVB ratio, and UVA1 to UV ratio, while maintaining a cosmetically elegant and stable formulation that resists water exposure and avoids undesirable residues.
Implementation Method 1
UV protective metal oxide particles
Implementation Method 2
particle matrix sunscreen composition
Data Source
AI summary
Matrix compositions suitable for topical administration comprising structurally diverse matrix particles formed from at least three different types of primary particle populations where (1) the first primary particle population has an average particle size from 1000 nm to 8500 nm, makes up 4-9% of the composition by weight, and 20-70% of the first primary particle population comprises a glass composition, (2) the second particle population has an average particle size from 250 nm to 500 nm, makes up 5-15% of the composition by weight and comprises UV-protective particles, and (3) the third particle population has an average particle size from 500 nm to 1000 nm, makes up 6.75-22% of the composition by weight, and at least 75% of the third particle population comprises UV-protective metal oxide particles, and the composition exhibits one or more of sun protection factor (SPF) of at least 30, a critical wavelength of at least 370 nm, UVA/UVB ratio of at least 0.333, and a UVA1 to UV ratio of at least 0.7.