Phospholipid Composition Stabilizing Fluorocarbon Emulsion
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Solution Overview
Problem
Current ultrasound contrast agents (USCA) like DEFINITY have a short shelf-life due to hydrolysis and cause back pain as a side effect in patients, primarily due to the presence of dipalmitoylphosphatidic acid (DPPA), which accelerates hydrolysis and leads to microbubble aggregation.
Innovation Solution
A phospholipid composition stabilizing a fluorocarbon emulsion with dipalmitoyl phosphatidylcholine (DPPC), phosphatidylethanolamine-PEG, and dipalmitoylphosphatidylethanolamine (DPPE) without DPPA, maintaining DPPE at 5-20 mole percent, forming stable microbubbles that do not aggregate and have improved patient tolerability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dipalmitoylphosphatidic acid (DPPA) is included in the ultrasound contrast agent formulation, then the initial microbubble formation and contrast enhancement are achieved, but the shelf-life is reduced due to accelerated hydrolysis and microbubble aggregation occurs
Solution Approach 1:
The invention removes DPPA from the lipid composition to eliminate the harmful hydrolysis reaction. The patent specifically states that DPPA undergoes hydrolysis to form free fatty acids which cause microbubble aggregation and reduce shelf-life. By extracting this problematic component while retaining DPPC and DPPE-PEG, the formulation achieves both initial microbubble formation and extended stability.
Solution Approach 2:
The invention changes the chemical composition parameters by substituting DPPE-PEG for DPPA in the lipid blend. This parameter change modifies the hydrolysis resistance and aggregation behavior of the microbubbles, extending shelf-life from months to potentially years while maintaining diagnostic performance through proper lipid ratio optimization.
2Reliability
If dipalmitoylphosphatidic acid (DPPA) is present in the formulation, then ultrasound contrast enhancement is provided, but back pain occurs in about 1.2% of patients as a side effect
Solution Approach 1:
The invention extracts DPPA from the formulation to eliminate the cause of back pain side effects. The patent explicitly links DPPA presence to back pain occurring in 1.2% of patients, and by removing this component while maintaining microbubble functionality through DPPC and DPPE-PEG, patient tolerability is improved without sacrificing diagnostic accuracy.
3Reliability
If the lipid composition includes DPPC, DPPE-PEG, and DPPA as in DEFINITY, then the product achieves approved diagnostic performance, but hydrolysis of the lipids degrades the product over time
Solution Approach 1:
The invention removes DPPA from the lipid composition to prevent hydrolysis degradation. The patent states that DPPA is primarily responsible for hydrolysis of the lipid composition, and by extracting this component while retaining DPPC and DPPE-PEG, the formulation achieves both diagnostic performance and hydrolysis resistance.
Solution Approach 2:
The invention creates a composite lipid material system using DPPC, DPPE-PEG, and optional additional phospholipids in specific ratios. This composite approach provides synergistic effects where DPPC offers structural integrity, DPPE-PEG provides steric stabilization, and the combination resists hydrolysis better than the DEFINITY formulation while maintaining microbubble formation and contrast enhancement capabilities.
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 composition extends shelf-life and reduces the incidence of back pain in patients by preventing hydrolysis and microbubble aggregation, maintaining microbubble stability and diagnostic efficacy comparable to DEFINITY.
Implementation Method 1
Hydrolysis of the lipids is primarily responsible for degradation of the product
Implementation Method 2
dipalmitoylphosphatidic acid (DPPA), which accelerates hydrolysis and leads to microbubble aggregation
Data Source
Figure 1
AI summary
A composition for stabilizing a fiuorocarbon. emulsion. That composition includes phosphatidylcholine, phosphatidylethanolamine-PEG, and a cone-shaped lipid.