HA-HAp Dermal Filler Composite for Longer Residence and Easier Injection
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Solution Overview
Problem
Existing dermal fillers based on hyaluronic acid (HA) and hydroxyapatite (HAp) exhibit additive effects rather than synergistic benefits, with HAp microspheres degrading quickly and HA degrading due to enzymatic, thermal, and mechanical forces, leading to short residence time and high viscosity, making them difficult to inject and maintain volume.
Innovation Solution
A composite material is formed by chemically bonding HA to HAp using coupling agents like organofunctional silanes, creating a covalent bond that slows down the degradation of both components, enhancing tissue augmentation and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If HA and HAp are used as separate components in dermal fillers, then tissue augmentation is achieved, but the residence time is short due to quick degradation of HAp and enzymatic degradation of HA
Solution Approach 1:
The patent combines HA and HAp into a single composite material where HA is chemically grafted onto HAp microspheres. This merging allows the two components to function together as one integrated system, preventing separate degradation pathways and enabling synergistic effects that prolong residence time while enhancing degradation resistance.
Solution Approach 2:
The invention creates a composite material consisting of HAp microspheres with grafted HA chains. This composite structure leverages the mechanical stability and slow degradation of HAp while incorporating the biocompatibility and tissue integration properties of HA, resulting in a material that exhibits both prolonged residence time and enhanced degradation resistance.
2Strength
If HA concentration is increased to maintain volume, then tissue augmentation is improved, but viscosity increases making injection difficult
Solution Approach 1:
The patent changes the structural parameters of HA by grafting it onto HAp microspheres rather than using free HA chains. This structural modification allows the formulation to maintain adequate HA concentration for volume support while the HAp scaffold prevents excessive viscosity buildup, enabling easier injection through fine gauge needles.
Solution Approach 2:
The composite structure of HAp microspheres with grafted HA creates a network that provides volume maintenance through the rigid HAp core while the flexible HA grafts provide lubricity and reduce overall viscosity, facilitating easier injection without sacrificing volume support capability.
3Reliability
If chemical crosslinking is used to enhance HA stability, then degradation resistance improves, but the formulation complexity and manufacturing difficulty increase
Solution Approach 1:
The HAp microsphere acts as an intermediary substrate that simplifies the crosslinking process. Instead of requiring complex crosslinking agents and multi-step procedures, the HA chains are directly grafted onto the HAp surface through silane chemistry, providing stable chemical bonding with reduced formulation complexity and streamlined manufacturing.
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 composite material achieves prolonged tissue augmentation with improved mechanical strength and resistance to enzymatic degradation, allowing for longer in vivo residence time and easier injection through fine gauge needles.
Implementation Method 1
chemically bonding HA to HAp using coupling agents like organofunctional silanes, creating a covalent bond
Implementation Method 2
resistance to enzymatic degradation
Data Source
AI summary
Compositions based on HA and HAp in the field of soft tissue fillers, and a method of manufacturing thereof. Optionally, the dermal fillers are useful for enhancing facial tissue augmentation by adding volume to facial tissue, correct wrinkles and folds and restore a smooth appearance to the face. Optionally, the dermal filler comprises uncrosslinked or crosslinked HA chemically bonded to HAp.