Formulation of lipid nanoparticles
The formulation of lipid nanoparticles as non-viral vectors has revolutionized the field of drug delivery, offering promising solutions for various therapeutic applications. The selection of lipids, including phospholipids, cholesterol, and ionizable lipids, impacts the stability, encapsulation efficiency, and release kinetics of LNPs. Additionally, excipients and surfactants can be incorporated to further optimize the formulation and enhance LNP performance.1
Liposomes, solid lipid nanoparticles (SLNs) and the resulting nanostructured lipid carriers have emerged as versatile platforms and alternative to polymers, capable of encapsulating a wide range of therapeutic molecules, including mRNA vaccines and plasmids. They have gained even more attention in the course of the SARS-CoV-2 pandemic and the development of novel mRNA vaccines, exemplified by the Pfizer-BioNTech COVID-19 vaccine.
Continuous optimization of lipid nanoparticle (LNP) formulation plays a crucial role in ensuring the efficient and targeted delivery of therapeutics for both in vitro and in vivo applications. By controlling particle size and achieving a narrow size distribution, the stability, biodistribution, and cellular uptake of LNPs can be improved. And with strategies in nanotechnology like PEGylation and aqueous-based formulations, concerns such as toxicity and an optimized immune response can be addressed.
Strategies for enhancing encapsulation efficiency, such as lipid-to-drug ratio optimization and co-encapsulation approaches, are being explored to maximize therapeutic payload capacity. Surface modification techniques involving ligand or antibody conjugation enable targeted mRNA delivery, enhancing interactions with specific cells or tissues. Additionally, factors like endosomal escape, intracellular gene delivery, and mitigation of issues like aggregation, cytotoxicity, and amyloidosis are intensely discussed in LNP development. But also considerations on diffusion, dispersion, endocytosis, filtration, and incorporation influence LNP formulation optimization.1