Ionizable Lipids with Degradable Ester Bonds for mRNA Delivery
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Solution Overview
Problem
Current ionizable lipids used in nucleic acid delivery, such as RNA vaccines, face challenges including dose-limiting toxicities like Complement Activation Related Pseudo-allergy and inflammatory cytokine release, due to non-degradable lipid accumulation in cellular membranes, necessitating improved lipid chemistries for enhanced efficacy and safety.
Innovation Solution
Development of a new class of ionizable lipids represented by specific formulas, which include various alkyl, alkenyl, and alkynyl moieties, heterocycles, and linkers, designed to improve mRNA encapsulation, cellular uptake, and endosomal escape while reducing toxicity, formulated into lipid nanoparticles with phospholipids and PEG lipids for stable and efficient delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current ionizable lipids are used for nucleic acid delivery, then mRNA encapsulation and cellular uptake are achieved, but dose-limiting toxicities occur due to non-degradable lipid accumulation in cellular membranes
Solution Approach 1:
The patent modifies the chemical structure of ionizable lipids by introducing degradable ester bonds at specific positions (R3 and R4 as C1-6 alkyl groups forming ester linkages), changing the chemical stability parameter to enable controlled degradation while maintaining delivery efficacy. This resolves the contradiction by allowing the lipid to fulfill its delivery function then degrade, preventing toxic accumulation.
Solution Approach 2:
The invention creates composite lipid structures combining stable head groups (for mRNA encapsulation and cellular uptake) with degradable tail sections (ester bonds that hydrolyze to fatty acids and alcohols). This composite approach maintains the beneficial delivery properties while introducing degradability to reduce toxicity from accumulation.
2Reliability
If ionizable lipids are used to govern mRNA encapsulation and cellular uptake, then delivery activity is improved, but inflammatory cytokine release and Complement Activation Related Pseudo-allergy occur
Solution Approach 1:
The patent changes the chemical stability parameter of the lipid by incorporating hydrolyzable ester bonds, transforming the lipid from permanently stable to temporarily stable. This allows the lipid to perform its delivery function (encapsulation, uptake) then degrade into less immunogenic products, reducing inflammatory cytokine release and CARPA reactions.
3Duration of action of stationary object
If non-degradable ionizable lipids accumulate in cellular membranes, then sustained delivery effect is achieved, but cellular toxicities occur
Solution Approach 1:
The patent introduces dynamic degradability into the lipid structure through ester bonds that hydrolyze over time. The lipid transitions from a static, permanently stable molecule to a dynamic molecule that degrades after performing its function. This resolves the contradiction by providing sufficient duration for delivery then enabling clearance to prevent toxicity.
Solution Approach 2:
The chemical structure is modified to include hydrolyzable ester linkages at R3 and R4 positions, changing the stability parameter from permanent to temporary. This allows the lipid to maintain structural integrity during delivery (providing sustained effect) then degrade into smaller, less toxic fragments (fatty acids, alcohols) that can be cleared from cellular membranes.
Data Source
AI summary
The present invention generally relates to the field of ionizable (also termed cationic) lipids, and in particular provides a novel type of such lipids as represented by formula (I). The present invention further provides methods for making such lipids as well as uses thereof, in particular in the preparation of nanoparticle compositions, more in particular nanoparticle compositions comprising nucleic acids. It further provides vaccine formulations comprising nanoparticle compositions based on the ionizable lipids disclosed herein.