Charge-Reversible Phospholipid for RNA Encapsulation With Low Cytotoxicity
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Solution Overview
Problem
Existing delivery systems for RNA-based pharmaceuticals face challenges due to RNA degradation and poor membrane penetration, necessitating a sophisticated delivery system that minimizes cytotoxicity and enhances encapsulation efficiency.
Innovation Solution
Development of a charge-reversible phospholipid with a specific structure that remains neutral at physiological pH, forming lipid particles that encapsulate medicinal substances efficiently and reduce cytotoxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a positively charged lipid is used to deliver negatively charged nucleic acid, then electrostatic interaction improves encapsulation efficiency, but cytotoxicity increases
Solution Approach 1:
The patent applies parameter changes by using a phospholipid whose charge state changes with pH. At acidic pH (endosomal environment), the phospholipid is positively charged to facilitate nucleic acid encapsulation through electrostatic interaction. At neutral pH (physiological environment), it becomes neutral or negatively charged to reduce cytotoxicity. This dynamic parameter change resolves the contradiction between encapsulation efficiency and safety.
Solution Approach 2:
The invention employs a dynamic charge-reversible phospholipid that transitions from a positively charged state during encapsulation to a neutral/negatively charged state during circulation. This dynamic property allows the delivery system to optimize encapsulation efficiency when needed while minimizing cytotoxicity during blood circulation, effectively resolving the technical contradiction.
2Reliability
If RNA is administered externally, then therapeutic effect can be achieved, but RNA degradation by nucleases reduces stability
Solution Approach 1:
The patent uses a lipid particle with a flexible lipid bilayer membrane to protect the encapsulated RNA from nuclease degradation. The lipid shell acts as a physical barrier that shields the RNA from enzymatic attack while allowing the therapeutic RNA to remain intact during circulation and delivery to target cells.
3Reliability
If a sophisticated delivery system is developed, then RNA penetration and stability improve, but device complexity increases
Solution Approach 1:
The invention employs a composite lipid particle system combining charge-reversible phospholipid, neutral phospholipid, and sterol in specific ratios. This composite structure provides both the sophistication needed for effective RNA delivery (encapsulation, protection, cellular uptake) and simplifies the overall system compared to more complex viral vectors or multi-component non-viral systems.
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 charge-reversible phospholipid enables effective encapsulation and delivery of medicinal substances like polynucleotides with reduced cytotoxicity, ensuring stability and safety.
Implementation Method 1
a charge-reversible phospholipid has siRNA encapsulation properties and safety at a physiological pH... when the charge-reversible phospholipid is a lipid particle that is not positively charged at a pH of the body fluid
Data Source
AI summary
The present invention provides a charge-reversible phospholipid that is not positively charged at a pH of the body fluid (typically in the neutral range) and has low cytotoxicity.The present invention provides a phospholipid represented by formula (1):wherein m represents a natural number of 9 to 25, n represents a natural number of 10 to 15, X1, X2, and X3 are the same or different and each represent H or OH, and R1 represents the following formula (i) or (ii):wherein p represents 1 or 2, q represents 1 or 2, and r represents an integer of 1 to 4; orwherein s represents an integer of 1 to 3, and R2 represents a hydrogen atom or a hydrocarbon group.