Lipid nanoparticles (LNPs) are widely used vehicles for oligonucleotide-based therapeutics and vaccines, which are composed of helper lipids, PEGylated lipids and ionizable lipids. LNPs can be susceptible to N-oxide-based impurities that can cause the loss of function of mRNA. The detailed characterization of LNPs and their related impurities is therefore important for developing successful products. In this webinar, we will show how an ionizable lipid, commonly known as DLin-MC3-DMA (MC3), was analyzed with liquid chromatography coupled to mass spectrometry (LC-MS) using electron-activated dissociation (EAD). EAD is a novel type of low-energy electron-impact fragmentation that permitted the detailed structural characterization of singly charged MC3. Structural elucidation was achieved for impurities present at <1%. We will also discuss how this analysis was used to localize double bonds and saturated impurities and differentiate between different oxidated species, including N-oxides. The presented technique can be expanded to other proprietary ionizable lipids, providing valuable information to ensure drug efficacy and safety and to enable the rational design of lipids used in LNPs.

 

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