Skin Sensitization Prediction for Personal Care Formulations

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Solution Overview

Problem

Existing methods for assessing skin sensitization potential in personal care products are time-consuming and inefficient due to the complex nature of formulations, requiring extensive human repeat insult patch testing and ingredient-by-ingredient analysis.

Innovation Solution

A method using binomial distribution and statistical analysis of ingredient sensitization data from a large sample size to predict skin sensitization risk, incorporating safety factors for real-world consumer use, allowing for the calculation of a 95% upper confidence limit to ensure product safety without additional testing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If human repeat insult patch testing (HRIPT) is used to assess skin sensitization potential, then reliability of sensitization assessment is improved, but time consumption increases significantly (at least eight weeks or more)

Engineering Contradiction:

Improvesensitization assessment reliabilityVSAvoidtesting time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by calculating upper confidence limits from ingredient sensitization data before conducting full HRIPT testing on finished products. This statistical pre-assessment filters out formulations with low sensitization risk, allowing only those exceeding predetermined thresholds to undergo time-consuming HRIPT testing, thereby significantly reducing overall testing time while maintaining reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent substitutes the mechanical HRIPT testing system with a statistical calculation system that uses binomial distribution to compute upper confidence limits from ingredient data. This computational approach replaces the physical, time-consuming patch testing mechanism with a rapid mathematical assessment that preserves reliability while eliminating time consumption

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If ingredient-by-ingredient testing is conducted to assess sensitization potential, then measurement precision is improved, but device complexity increases due to multiple testing requirements

Engineering Contradiction:

Improvesensitization potential precisionVSAvoidtesting system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple ingredient-level sensitization assessments into a single finished product formulation assessment by calculating the upper confidence limit of the sum of sensitization potentials. This combines individual ingredient data with formulation concentration information to produce one comprehensive precision metric, eliminating the need for separate testing systems for each ingredient

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal assessment system that handles both individual ingredient evaluation and finished product formulation assessment through the same statistical methodology. The upper confidence limit calculation serves multiple functions: assessing single ingredients, evaluating complete formulations, and determining whether HRIPT testing is required, thereby reducing system complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If larger HRIPT sample size is used to improve statistical probability of detecting population sensitivity, then reliability is improved, but loss of time and resources increases

Engineering Contradiction:

Improvepopulation sensitivity detection reliabilityVSAvoidsample testing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies partial action by using a predetermined confidence threshold (e.g., 95% upper confidence limit) rather than requiring exhaustive testing of entire populations. This threshold-based approach provides sufficient reliability for regulatory and safety decisions without the time and resource costs of complete population testing, achieving adequate statistical power through controlled sampling

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS20250375149A1Method for improving the real-world skin sensitization impact of formulated products

Publication Date: 2025.12.11 KENVUE BRANDS LLC

AI summary

A method of predictively assessing skin sensitization of a personal care product formulation includes: calculating an upper confidence limit at a desired confidence level from multiple physical tests for skin sensitization of each of the ingredients in the personal care product formulation to define calculated skin sensitization values for the respective ingredients; applying at least one safety factor to at least one of the calculated skin sensitization values for the ingredients to define adjusted skin sensitization values for the respective ingredients; summing the adjusted skin sensitization values of the ingredients to define a total sensitization of the personal care product formulation; and comparing the total sensitization to a target product sensitization for the personal care product formulation. Such personal care product formulations do not require further testing and are capable of application to skin by users. Predictive systems and methods of preparing a personal care products are also disclosed.