Gas-Filled Microvesicle Stability via Fatty Acid Mixtures

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Solution Overview

Problem

Phospholipid-based gas-filled microvesicles for ultrasound contrast imaging and therapeutic applications face stability challenges, particularly when formulated with either saturated or unsaturated fatty acids alone, which can lead to reduced durability in physiological environments.

Innovation Solution

Incorporating a mixture of saturated and unsaturated fatty acids in the stabilizing layer of gas-filled microvesicles, with specific molar ratios between 2.5:1 to 1:8, enhances the stability of the microvesicles compared to formulations using only one type of fatty acid.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gas-filled microvesicles are formulated with only saturated or only unsaturated fatty acids in the stabilizing layer, then the formulation is simpler, but the stability and durability in physiological environments is reduced

Engineering Contradiction:
Improvestability of microvesiclesVSAvoidcomplexity of stabilizing layer formulation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The stabilizing layer is formulated as a composite material containing both saturated and unsaturated fatty acids in specific proportions (0.1-10 mmol saturated, 0.1-5 mmol unsaturated). This composite approach combines the advantages of both fatty acid types: saturated fatty acids provide structural stability while unsaturated fatty acids enhance membrane flexibility and durability, resulting in microvesicles with improved overall stability in physiological environments

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention optimizes specific parameters of the stabilizing layer formulation, including the molar ratios of different fatty acids (saturated vs unsaturated), the total amount of fatty acids (0.2-20 mmol), and the combination with phospholipids (0.1-10 mmol). These parameter optimizations directly enhance the stability and performance of the microvesicles without excessive complexity

Inventive Principle:
Principle #35Parameter changes

2Duration of action of stationary object

If a mixture of saturated and unsaturated fatty acids is used in the stabilizing layer, then the stability and durability of microvesicles is improved, but the formulation complexity increases

Engineering Contradiction:
Improvedurability of microvesiclesVSAvoidcomplexity of formulation
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The stabilizing layer employs a composite formulation combining saturated fatty acids (providing long-term structural stability) and unsaturated fatty acids (providing membrane flexibility and resistance to oxidation). This composite material approach extends the duration of action and durability of the microvesicles in physiological environments while maintaining a manageable formulation through defined concentration ranges

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different regions of the stabilizing layer benefit from different fatty acid compositions: the phospholipid-fatty acid interface utilizes saturated fatty acids for structural integrity, while the outer membrane surface benefits from unsaturated fatty acids for flexibility and interaction with physiological environments. This local quality differentiation enhances overall durability

Inventive Principle:
Principle #3Local quality

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 use of a mixture of saturated and unsaturated fatty acids in the stabilizing layer significantly increases the stability of gas-filled microvesicles, improving their durability and performance in diagnostic imaging and therapeutic applications.

Implementation Method 1

the bubbles of gas are bounded at the gas/liquid interface by a very thin envelope (film) involving a stabilizing amphiphilic material (typically a phospholipid) disposed at the gas to liquid interface

Methodology Applied
Scientific EffectAmphiphilic material stabilization: Amphiphiles

Implementation Method 2

a stabilizing envelope comprising a phospholipid, a saturated fatty acid and an unsaturated fatty acid

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP2934740B1Gas-filled microvesicles
Publication Date: 2019.12.11 BRACCO SUISSE SA

AI summary

A formulation for preparing gas-filled microvesicles which comprises a phospholipid and a mixture of saturated and unsaturated fatty acids. The gas-filled microvesicles having a stabilizing layer comprising said composition show an increased stability with respect to microvesicles containing only a saturated or an unsaturated fatty acid.