LNP Purification via Convective Chromatography
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Solution Overview
Problem
Current methods for purifying lipid nanoparticles (LNPs) encapsulating nucleic acids, such as mRNA, face challenges with low recovery and purity due to shear-sensitive nature and co-purification of non-encapsulated nucleic acids, particularly when using tangential flow filtration (TFF) which generates high shear forces and requires molecular weight cutoffs smaller than the mRNA size.
Innovation Solution
The method involves using a chromatographic medium with convective flow properties in the presence of a kosmotropic agent for selective binding and elution of LNPs, minimizing shear forces and allowing for simultaneous concentration, buffer exchange, and purification of LNPs while excluding impurities, using monolithic chromatographic media with hydroxyl ligands and kosmotropic salts like potassium phosphate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If tangential flow filtration (TFF) is used for buffer exchange and purification of LNPs, then organic solvent removal and concentration are achieved, but high shear forces and turbulences cause LNP degradation and low recovery
Solution Approach 1:
The patent replaces the mechanical TFF system with a chromatographic system operating under convective flow conditions. Instead of using high shear mechanical filtration, the invention uses a chromatographic medium where LNPs are separated based on their interaction with the medium under gentle convective flow, eliminating the mechanical stress that causes LNP degradation while maintaining efficient buffer exchange and concentration capabilities
2Manufacturing precision
If TFF with small molecular weight cutoff is used to separate LNPs from non-encapsulated mRNA, then purification is achieved, but co-purification of non-encapsulated mRNA occurs
Solution Approach 1:
The patent changes the separation parameter from molecular weight cutoff (physical size-based separation) to chromatographic interaction properties (chemical/physical affinity-based separation). By using a chromatographic medium with specific convective flow properties, the system can differentiate between encapsulated mRNA within LNPs and free non-encapsulated mRNA based on their different interactions with the chromatographic medium, achieving purification without co-purification of contaminants
3Productivity
If high pressure in-line mixing is used for LNP formulation, then encapsulation efficiency is improved, but organic solvent content increases which is detrimental to LNP stability
Solution Approach 1:
The patent performs buffer exchange and organic solvent removal as preliminary actions before final LNP formulation and storage. By using the chromatographic method to remove organic solvents and exchange buffers in advance, the LNP stability is ensured for subsequent handling, storage, and administration, while the high pressure in-line mixing step maintains encapsulation efficiency during the formulation process
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 approach increases the yield and purity of LNPs by reducing shear-induced degradation and effectively differentiating between encapsulated LNPs and free nucleic acids, enhancing clinical efficacy and scalability for industrial production.
Implementation Method 1
subjecting a solution containing said LNPs to a chromatographic medium with convective flow properties in the presence of at least one kosmotropic agent
Implementation Method 2
subjecting a solution containing said LNPs to a chromatographic medium with convective flow properties
Implementation Method 3
in the presence of at least one kosmotropic agent
Implementation Method 4
chromatographic medium with convective flow properties
Data Source
Figure 1
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AI summary
The present invention relates to methods for the purification of lipid nanoparticles (LNPs) encapsulating a nucleic acid, comprising the steps of subjecting a solution containing said LNPs to a chromatographic medium with convective flow properties in the presence of at least one kosmotropic agent; and eluting LNPs from said chromatographic medium. The present invention further relates to respective uses of a chromatographic medium with convective flow properties for the purification of lipid nanoparticles (LNPs) encapsulating a nucleic acid.