Lyophilized Matrix Microbubble Preparation

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Solution Overview

Problem

Existing methods for preparing ultrasound contrast agents using gas microbubbles are limited by high agitation energy requirements, which can lead to phospholipid degradation and uncontrollable size distribution, and often result in low yield and broad size distribution of microbubbles.

Innovation Solution

A process involving the preparation of an aqueous-organic emulsion with more than 50% phospholipid and a lyoprotectant, followed by lyophilization, to produce a lyophilized matrix that forms a suspension of gas-filled microbubbles with a narrow size distribution when reconstituted, using controlled agitation and a rotor-stator homogenizer or micromixing techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high agitation energy is applied to generate gas microbubble suspensions, then microbubble formation is achieved, but phospholipid degradation occurs and size distribution becomes uncontrollable

Engineering Contradiction:
Improvemicrobubble formation yieldVSAvoidmicrobubble size distribution control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the physical and chemical parameters of the system by using a specifically designed amphiphilic polymer with controlled molecular weight and composition. This polymer modifies the interfacial properties and allows microbubble formation at lower agitation energies, thereby maintaining size distribution control while reducing phospholipid degradation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The amphiphilic polymer acts as an intermediary substance that mediates between the gas phase and aqueous medium. It stabilizes the gas-liquid interface and enables microbubble formation without requiring excessive agitation energy, thus preventing phospholipid degradation and maintaining controlled size distribution

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If high agitation energy is applied to generate gas microbubble suspensions, then microbubble suspension is formed, but phospholipid degradation occurs

Engineering Contradiction:
Improvemicrobubble suspension formationVSAvoidphospholipid degradation
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The amphiphilic polymer serves as a protective intermediary that shields phospholipids from degradation during microbubble formation. It stabilizes the gas-liquid interface and reduces the mechanical stress on phospholipids, allowing microbubble suspension formation without significant phospholipid loss

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The amphiphilic polymer provides beforehand cushioning by pre-establishing a stable interfacial layer before microbubble formation. This protective layer cushions against the mechanical stresses of agitation, preventing phospholipid degradation while still allowing microbubble suspension to form

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Quantity of substance

If conventional methods are used to prepare contrast agents, then gas bubbles are formed, but yield is low and size distribution is broad

Engineering Contradiction:
Improvegas bubble concentrationVSAvoidmicrobubble size distribution
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent optimizes parameters including the molecular weight, composition, and concentration of the amphiphilic polymer to achieve optimal microbubble formation. These parameter changes enable higher gas bubble concentration while maintaining narrow size distribution through controlled interfacial stabilization

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The amphiphilic polymer provides local quality enhancement by creating specifically tailored interfacial properties at the gas-liquid boundary. Its molecular structure and composition are designed to provide localized stabilization that promotes uniform microbubble formation with controlled size distribution

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

This method achieves microbubbles with a narrow size distribution and increased yield, reducing phospholipid degradation and agitation energy requirements, resulting in stable and effective ultrasound contrast agents for diagnostic imaging.

Implementation Method 1

a process involving the preparation of an aqueous-organic emulsion with more than 50% phospholipid and a lyoprotectant, followed by lyophilization, to produce a lyophilized matrix that forms a suspension of gas-filled microbubbles

Methodology Applied
Scientific EffectLyophilization: Freeze Drying

Implementation Method 2

preparation of an aqueous-organic emulsion comprising an aqueous medium, an organic solvent substantially immiscible with water, an emulsifying composition of amphiphilic materials comprising more than 50% by weight of a phospholipid

Methodology Applied
Scientific EffectEmulsion formation: Emulsion

Data Source

PatentUS9364569B2Ultrasound contrast agents and process for the preparation thereof
Publication Date: 2016.06.14 BRACCO SUISSE SA

AI summary

Method for preparing a lyophilized matrix and, upon reconstitution of the same, a respective injectable contrast agent comprising a liquid aqueous suspension of gas-filled microbubbles stabilized predominantly by a phospholipid. The method comprises preparing an emulsion from an aqueous medium, a phospholipid and a water immiscible organic solvent. The emulsion is then freeze-dried and subsequently reconstituted in an aqueous suspension of gas-filled microbubbles. The method allows to obtain suspensions comprising microbubbles having a relatively small diameter and a narrow size distribution.