Abstract
The unprecedented safety, efficacy and development speed of the mRNA-based Covid-19 vaccines demonstrated with dramatic impact the potential of mRNA encapsulated into lipid nanoparticles (mRNA-LNPs) as medicines. Currently, a wide range of mRNA-LNP-based vaccines and therapeutics are in preclinical development and clinical testing, with indications ranging from bacterial and viral infections, to autoimmune diseases and cancer. However, mRNA-LNPs are highly complex, nanosized particulate drugs with unique analytical and preparative requirements. Formulation of the mRNA (or other nucleic acids) in the LNPs is done in a microfluidics-based co-precipitation process of the nucleic acids with lipids. Post-formulation processing, including purification, is done today by dialysis in lab scale and by tangential flow filtration (TFF). However, dialysis is not applicable at preparative scale, and TFF has important limitations and shortcomings, including poor scalability, high loss of the drug product at late process stages, shear stress impacting colloidal stability, and limited transferability of methods between projects.
The recent publication [1] of monolithic liquid chromatography (mLC) as a method to analyse intact LNPs based on their surface chemistry is groundbreaking and has important implications also for preparative use. SINTEF has worked on the use of preparative mLC as an attractive alternative to TFF. We show here the successful use of preparative mLC for purification of mRNA-LNPs, verified by extensive physicochemical analytics, in vitro cell assays and finally in vivo mRNA expression and safety analysis. Firefly luciferase mRNA expression and safety was not significantly different between different purification methods, indicating mLC as a highly attractive method for improving the clinical translation of mRNA-LNPs.