pH-Sensitive Microcapsules for Controlled Release in Oral Care
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Solution Overview
Problem
Existing oral care, personal care, and home care compositions face challenges with instability, incompatibility of components, and inefficient release of functional ingredients, particularly due to issues like solubility changes caused by organic acids and settling of larger delivery agents, which affect their stability and effectiveness.
Innovation Solution
The use of pH-sensitive microcapsules with a shell wall comprising hydroxypropyl methyl cellulose phthalate and shellac, along with optional anionic copolymers, which are stable at acidic pH and release functional ingredients when the pH increases, such as upon contact with saliva or water, ensuring controlled and sustained release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic acids are used in oral care compositions to provide functional benefits, then therapeutic efficacy is improved, but stability deteriorates due to solubility changes and polymer precipitation
Solution Approach 1:
The patent segments the delivery system into pH-sensitive microcapsules that encapsulate functional ingredients. This segmentation allows the organic acids to be delivered in a controlled manner, separating the therapeutic function from the stability issue by protecting the acids within the microcapsule structure until release is needed.
Solution Approach 2:
The patent utilizes pH-sensitive microcapsules that change their properties based on pH parameter changes. The microcapsules are designed to dissolve or release their contents when the pH increases (e.g., upon contact with saliva), allowing the organic acids to be released only when needed while remaining stable in the acidic formulation during storage.
2Quantity of substance
If larger-sized delivery agents are used to increase functional ingredient concentration, then release concentration is improved, but suspension stability deteriorates leading to settling
Solution Approach 1:
The patent changes the size parameter of delivery agents by using microcapsules with controlled dimensions (typically 1-100 micrometers). This parameter optimization allows sufficient concentration of functional ingredients while maintaining suspension stability, as the microcapsule size is small enough to remain dispersed but large enough to encapsulate effective amounts of active ingredients.
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
This approach enhances the stability and delivery profiles of compositions, allowing for optimal adhesion, timing, and concentration of functional ingredient release, improving both aesthetic and therapeutic benefits while maintaining stability over extended periods.
Implementation Method 1
a pH-sensitive microcapsule that is soluble above a threshold pH
Data Source
AI summary
Disclosed herein is a composition comprising a pH-sensitive microcapsule comprising (1) a shell wall comprising at least one polymer chosen from cellulose derivatives and acrylate derivatives, and at least one structuring agent chosen from shellac, ethyl cellulose, and fumed silica, and (2) at least one functional ingredient encapsulated inside the shell wall; and a carrier having a pH of less than about 7. Further disclosed herein are methods of making a composition comprising a pH-sensitive microcapsule.