Solid UV Filters with Heptanediols for Solubility

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Solution Overview

Problem

Existing sunscreen compositions face challenges in achieving high Sun Protection Factor (SPF) while maintaining low solid UV filter concentrations to avoid high costs and compromised solubility, leading to recrystallization and poor sensory properties.

Innovation Solution

Incorporating 1,2-heptanediol, 2,3-heptanediol, or a mixture of specific alkanediols with solid UV filters improves solubility and stability, preventing recrystallization, and enhances skin sensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high levels of UVA and UVB sunscreens are incorporated to achieve high SPF, then UV protection efficacy is improved, but the cost of the composition increases and sensory properties are compromised

Engineering Contradiction:
ImproveUV protection efficacyVSAvoidsensory properties
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses solid UV filters as intermediary substances that provide UV protection through physical absorption rather than relying on high concentrations of conventional liquid sunscreens. This mediator approach allows achieving high SPF while avoiding the sensory drawbacks associated with high levels of traditional sunscreen agents.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical state parameter of UV filters from liquid to solid form. This parameter change enables the use of UV filters in a different phase that provides protection without the sensory issues (greasiness, residue) associated with high concentrations of liquid sunscreen agents.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If high levels of sunscreens are incorporated to achieve high SPF, then UV protection efficacy is improved, but the total amount of sunscreens must be kept relatively low to maintain sensory properties

Engineering Contradiction:
ImproveSPFVSAvoidtotal amount of sunscreens
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the concentration parameter by using solid UV filters that provide equivalent or superior protection at lower quantities compared to liquid sunscreen agents. This parameter change resolves the contradiction between achieving high SPF and minimizing the total amount of sunscreen substances.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite formulation combining solid UV filters with cosmetic ingredients. This composite approach allows achieving high SPF protection while maintaining low overall sunscreen content, as the solid filters provide intense protection per unit mass.

Inventive Principle:
Principle #40Composite materials

3Stability of the object's composition

If solid UV filters with melting points above 40°C are used, then stability and storability are improved, but solubility is compromised leading to recrystallization

Engineering Contradiction:
ImprovestorabilityVSAvoidsolubility
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent changes the temperature parameter by formulating the composition to maintain the solid UV filters in a melted or softened state during application. This parameter change allows the insoluble solid filters to become sufficiently soluble at application temperature while maintaining their stability and preventing recrystallization during storage.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention addresses the solubility problem by introducing a temperature dimension to the formulation. The solid UV filters are designed to be stable at storage temperatures but become soluble when the composition is warmed to application temperature, thus resolving the contradiction between stability and solubility through dimensional change.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 addition of alkanediols results in stable sunscreen formulations with improved solubility and sensory properties, maintaining UV filter availability and reducing greasy feel.

Implementation Method 1

Incorporating 1,2-heptanediol, 2,3-heptanediol, or a mixture of specific alkanediols with solid UV filters improves solubility and stability, preventing recrystallization

Methodology Applied
Scientific EffectSolubility enhancement: Solvation

Implementation Method 2

UV filters are compounds which have a pronounced absorption capacity for ultraviolet radiation

Methodology Applied
Scientific EffectUV absorption: Absorption (EM radiation)

Data Source

PatentEP4706780A2Compositions comprising UV-filters and one or more (BIO)-alkanediols
Publication Date: 2026.03.11 SYMRISE GMBH & CO KG
  • EP4706780A2 patent drawingFigure 1~2
  • EP4706780A2 patent drawingFigure 3~4
  • EP4706780A2 patent drawingFigure 5

AI summary

The present invention refers in general to the area of sun care products and relates in particular to a cosmetic or pharmaceutical, in particular dermatological, composition or a homecare product comprising or consisting of a solid UV filter and an effective amount of 1,2-heptanediol and/or 2,3-heptanediol or of a specific alkanediol or a mixture of two or more different specific alkanediols and the use of said compositions as a cosmetic, for personal care, as a pharmaceutical, for animal care or as a homecare product. Additionally, the present invention relates to the use of 1,2-heptanediol and/or 2,3-heptanediol or of a specific alkanediol or a mixture of two or more different specific alkanediols for improving the solubility of a solid UV filter, and/or for improving the availability of a solid UV filter in a cosmetic or pharmaceutical composition or homecare product.