Measuring Particle Size Distribution by AsymmetricFlow Field Flow Fractionation: A Powerful Method for the PreclinicalCharacterization of Lipid-Based Nanoparticles

摘要

Particle size distribution and stability are key attributes for the evaluation of the safety and efficacy profile of medical nanoparticles (Med-NPs). Measuring particle average size and particle size distribution is a challenging task which requires the combination of orthogonal high-resolution sizing techniques, especially in complex biological media. Unfortunately, despite its limitations, due to its accessibility, low cost, and easy handling, batch mode dynamic light scattering (DLS) is still very often used as the only approach to measure particle size distribution in the nanomedicine field. In this work the use of asymmetric flow field flow fractionation coupled to multiangle light scattering and dynamic light scattering detectors (AF4-MALS-DLS) was evaluated as an alternative to batch mode DLS to measure the physical properties of lipid-based nanoparticles. A robust standard operating procedure (SOPs) developed by the Nanomedicine Characterization Laboratory (EUNCL) was presented and tested to assess size stability, batch to batch consistency, and the behavior of the lipid-based nanoparticlesin plasma. Orthogonal sizing techniques, such as transmission electronmicroscopy (TEM) and particle tracking analysis (PTA) measurements,were performed to support the results. While batch mode DLS couldbe applied as a fast and simple method to provide a preliminary insightinto the integrity and polydispersity of samples, it was unsuitableto resolve small modifications of the particle size distribution.The introduction of nanoparticle sorting by field-flow fractionationcoupled to online DLS and MALS allowed assessment of batch to batchvariability and changes in the size of the lipid nanoparticles inducedby the interaction with serum proteins, which are critical for qualitycontrol and regulatory aspects. In conclusion, if a robust SOP isfollowed, AF4-MALS-DLS is a powerful method for the preclinical characterizationof lipid-based nanoparticles.