PEG Stabilizer for Freeze-Dried Ultrasound Microvesicles
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Solution Overview
Problem
Calibrated microvesicles used in ultrasound contrast agents face challenges in maintaining their size distribution and concentration stability during freeze-drying, which affects their shelf life and pharmaceutical applications.
Innovation Solution
Incorporating polyethylene glycol (PEG) as a freeze-drying protecting component at specific concentrations to preserve the geometric standard deviation (GSD) and concentration of calibrated gas-filled microvesicles during the freeze-drying process, ensuring the reconstituted suspension maintains acceptable characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If freeze-drying is applied to extend shelf life, then storage stability is improved, but size distribution and concentration characteristics deteriorate
Solution Approach 1:
A freeze-drying stabilizer is introduced as an intermediary substance during the freeze-drying process. This stabilizer protects the calibrated microvesicles from damage during lyophilization, maintaining their size distribution (GSD ≤ 1.22) and concentration characteristics while enabling long-term storage stability.
Solution Approach 2:
The patent optimizes specific parameters of the freeze-drying process including temperature, pressure, and duration to minimize damage to microvesicles. By carefully controlling these parameters and using appropriate stabilizer concentrations, the process achieves both extended shelf life and preservation of size distribution characteristics.
2Duration of action of stationary object
If freeze-drying is applied to improve storage stability, then shelf life is extended, but concentration characteristics deteriorate
Solution Approach 1:
The freeze-drying stabilizer acts as a protective intermediary that prevents loss of microvesicles during the freeze-drying process. It maintains the concentration characteristics by preventing aggregation, adhesion to chamber walls, and degradation, thereby preserving the quantity of active substance after reconstitution.
Solution Approach 2:
The stabilizer is added beforehand to the microvesicle suspension before freeze-drying begins. This prior cushioning protects the microvesicles from the harsh freeze-drying conditions, ensuring that concentration characteristics are maintained throughout the storage period.
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 PEG effectively maintains the initial characteristics of calibrated microvesicles, such as GSD and concentration, after reconstitution, enhancing their stability and suitability for long-term storage and pharmaceutical use.
Implementation Method 1
Freeze-drying, also known as lyophilization, is a complex and challenging process, widely used in the pharmaceutical industry that has the advantage of preserving pharmaceutical products under a dry form over several months.
Implementation Method 2
The reconstituted suspension of microvesicles have a geometric standard deviation (GSD) value of at least 1.22 or lower
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention generally relates to the field of ultrasound contrast-agents (USCA). In particular, it relates to a freeze-dried composition comprising an amphiphilic material and a freeze-drying protecting component, which may be reconstituted for preparing a suspension of gas-filled microvesicles with calibrated size, useful in diagnostic or therapeutic applications. It further relates to the method for the preparation of such freeze-dried composition.