Rapid quality evaluation of lipid nanoparticles using a monolithic HPLC column

The quality assurance of lipid nanoparticles (LNPs) is important for the effectiveness and safety of drugs. We developed a simple high-performance liquid chromatography (HPLC) method for rapid quality assessment of LNPs. LNPs prepared by a microchemical process were analyzed using a Tris gradient mobile phase and a poly-Lys–modified monolith as the stationary phase. This analysis produced two peaks at ~ 1 and 5 min. The fractions were collected and examined for particle morphology and zeta potential. The 1-min peak contained 20–40 nm nanoparticles, while the 5-min peak corresponded to LNPs. We applied this method to evaluate LNP stability after dilution with Tris buffer and exposure to 100 mM Ca²⁺. LNPs degraded within 1 day in Ca²⁺ at 4 °C, but > 85% remained intact after 3 days in a 500-fold Tris buffer dilution. This method enables LNP analysis within 10 min and provides a useful tool for LNP quality control.