Two-Step Sunscreen Delivery for High SPF and UVAPF
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Solution Overview
Problem
Existing sunscreen delivery methods, including wash-off and leave-on compositions, face challenges in achieving high Sun Protection Factor (SPF) and UV-A Protection Factor (UVAPF) due to limitations in sunscreen deposition and synergistic benefits when used sequentially.
Innovation Solution
A two-step method involving a wash-off composition with water-soluble UV-A and UV-B sunscreens, followed by a leave-on composition, to enhance sunscreen deposition and achieve synergistic SPF and UVAPF benefits, using specific surfactants and cosmetically acceptable carriers to ensure high solubility and effective skin interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If wash-off products are used to deliver sunscreens, then the primary purpose is to remove dirt and oils from the skin surface, but the actives in the wash-off products are highly likely to get washed away and enhanced deposition is difficult to achieve
Solution Approach 1:
The sunscreen delivery system is segmented into two distinct steps: a wash-off step with water-soluble sunscreens that provide initial deposition and cleaning, followed by a leave-on step with conventional sunscreens that provide sustained protection. This segmentation allows each step to optimize for its specific function while achieving cumulative high SPF protection.
Solution Approach 2:
The invention changes the solubility parameter of the sunscreen agents between the two steps. Water-soluble sunscreens are used in the wash-off step to enable effective deposition during rinsing, while conventional (less water-soluble) sunscreens are used in the leave-on step to ensure retention and sustained protection. This parameter change resolves the contradiction between deposition and retention.
2Quantity of substance
If higher amount of sunscreens are incorporated in leave-on compositions, then SPF protection is improved, but the deposition efficacy does not continuously enhance and formulation complexity increases
Solution Approach 1:
Instead of continuously increasing sunscreen concentration in a single leave-on formulation, the system segments the sunscreen delivery into two distinct steps with different functional requirements. This allows optimal concentration levels in each step without compromising formulation stability or creating excessive complexity.
Solution Approach 2:
The invention creates a composite sunscreen protection system combining water-soluble sunscreens from the wash-off step with conventional sunscreens from the leave-on step. This composite approach achieves synergistic SPF enhancement greater than either step alone, while maintaining manageable formulation complexity through clear functional differentiation.
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 method delivers enhanced SPF and UVAPF values, exceeding 15 and 4 respectively, with optimal deposition of sunscreens, providing superior protection against UV-A and UV-B radiation.
Implementation Method 1
These cosmetic compositions usually comprise different types of organic sunscreen agents, especially ones capable of absorbing the UV-A and/or UV-B radiation present in the sun's rays
Implementation Method 2
The method comprises the step of washing the skin with a composition comprising water soluble sunscreens followed by the step of applying a leave-on sunscreen composition on to skin
Data Source
AI summary
The present invention relates to a method of delivering high Sun Protection Factor (SPF) and UVA protection factor (UVAPF) to a topical surface of a body preferably the human body. The method more preferably provides for synergistic benefit of SPF and UVA PF over and above that which can be delivered through each of two individual steps carried out sequentially viz. washing off the skin with a specific cleansing composition followed by the step of applying a sunscreen composition on to the same skin surface. The specific cleansing composition comprises water soluble sunscreens but the leave-on composition could comprise any sunscreen.