Abstract
Development and use of mRNA vaccines and therapeutics is crucially dependent on safe, efficient and manufacturable delivery vectors. Beyond viral vectors, lipid nanoparticles (LNPs) have emerged as the lead delivery platforms, convincingly demonstrated in the Covid-19 mRNA vaccines and in a wide range of ongoing clinical trials.
Nanoparticle-based delivery vectors, even fully synthetic like LNPs, are complex systems that have very distinct requirements in terms of analytics and characterization, both for rational development, during scale-up and in clinical manufacturing. Analytical methods for small molecules, peptides or protein drugs are frequently not suited for nanoparticles, and novel drug attributes are considered critical, like particle size and size distribution.
In the current work, the selection, suitability and application of analytical methods – and their orthogonality and complementarity, as requested by regulatory authorities – is presented, based on comprehensive comparisons and interlaboratory studies we have performed. A tiered analytical approach is proposed, from the early screening by batch methods like dynamic light scattering (DLS) or nanoparticle tracking analysis (NTA) to more in-depth analyses with e.g. multi-detector field flow fractionation (MF-FFF), differential scanning calorimetry (DSC) and analytical ultracentrifugation (AUC). We show that the latter methods are crucial to discover more subtle differences in LNP quality that are important for biological activity. The drug substance – mRNA – is an equally challenging analyte, and methods based on e.g. capillary gel electrophoresis (CGE) and mass spectrometry (LC-MS/MS) are useful.
Finally, a novel separation technique for intact LNPs based on their surface chemistry is presented. Beyond the new analytical opportunities, this could also hold significant potential to facilitate purification and buffer exchange on a large preparative scale, alleviating challenges inherent to the current dialysis and tangential flow filtration (TFF) methods used extensively in both academia and industry.
Nanoparticle-based delivery vectors, even fully synthetic like LNPs, are complex systems that have very distinct requirements in terms of analytics and characterization, both for rational development, during scale-up and in clinical manufacturing. Analytical methods for small molecules, peptides or protein drugs are frequently not suited for nanoparticles, and novel drug attributes are considered critical, like particle size and size distribution.
In the current work, the selection, suitability and application of analytical methods – and their orthogonality and complementarity, as requested by regulatory authorities – is presented, based on comprehensive comparisons and interlaboratory studies we have performed. A tiered analytical approach is proposed, from the early screening by batch methods like dynamic light scattering (DLS) or nanoparticle tracking analysis (NTA) to more in-depth analyses with e.g. multi-detector field flow fractionation (MF-FFF), differential scanning calorimetry (DSC) and analytical ultracentrifugation (AUC). We show that the latter methods are crucial to discover more subtle differences in LNP quality that are important for biological activity. The drug substance – mRNA – is an equally challenging analyte, and methods based on e.g. capillary gel electrophoresis (CGE) and mass spectrometry (LC-MS/MS) are useful.
Finally, a novel separation technique for intact LNPs based on their surface chemistry is presented. Beyond the new analytical opportunities, this could also hold significant potential to facilitate purification and buffer exchange on a large preparative scale, alleviating challenges inherent to the current dialysis and tangential flow filtration (TFF) methods used extensively in both academia and industry.