Facile scalable one-flow synthesis of ionizable cationic lipid library as precursors of nanoparticle carriers

• Published in: International journal of pharmaceutics Vol. 662; p. 124513
• Main Authors: Kawale, Sanket A., Na, Gi-Su, Kumar, Sanjeev, Joo, Jeong-Un, Kang, Dong-Chang, Kim, Dong-Pyo
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05.09.2024
• Subjects: Cationic lipids; Flow chemistry; Ionizable lipids; Lipid nanoparticle; Liposome; Liposome; Ionizable lipids; Flow chemistry; Lipid nanoparticle; Cationic lipids
• ISSN: 0378-5173; 1873-3476; 1873-3476
• DOI: 10.1016/j.ijpharm.2024.124513

A streamlined process enables the synthesis of a variety of ionizable and cationic lipids, including DODAP and DOTAP, with scalable production. Key steps involve moisture-sensitive acyl chloride generation and efficient removal of toxic byproducts, leading to the formation of uniform-sized lipid nanoparticles and liposomal nanoparticles. This platform offers significant advancements in lipid-based nanomedicines, enhancing drug delivery systems’ efficacy and safety. [Display omitted] •One-flow synthesis of biodegradable ionizable lipid library.•Continuous monitoring with in-situ FTIR.•Cationic lipids synthesis via rapid flow alkylation & Steglich esterification.•Rapid flow synthesis of LNPs & liposomes for nucleic acid delivery. A variety of ionizable and cationic lipids have been synthesized as precursors for nanoparticle carriers. However, the laborious synthetic routes in batch reactors often involve the use of toxic and carcinogenic agents, as well as challenge of removing gaseous byproducts. In this study, we present facile one-flow micro-reaction process that enables the synthesis of 11 ionizable lipids as well as 7 cationic lipids, including the well-known DODAP and DOTAP. These lipids can be scaled up to produce approximately ∼10g/h by using a straightforward size-up approach. The development of the lipid library was involved generating highly moisture-sensitive acyl chloride at 25 °C for 1.5 min. The toxic byproducts such as HCl, CO2 and CO were subsequently removed using a liquid–gas separator. The esterification with dimethylamino-1,2-diol at 25 °C for 3 min, monitored in-line with FTIR, completed the process. Additionally, the synthesized ionizable lipids were converted to cationic lipids with methyl sulfate, chloride ions via dimethyl sulfate and Steglich esterification in a continuous flow system. Finally, the produced DODAP was transformed into a uniform-sized LNPs (64 nm, PDI 0.07) and liposomal nanoparticles (72 nm, PDI 0.05) while DOTAP was converted to liposomes (55 nm, PDI 0.08) using a custom micro-mixer. This efficient platform for lipid synthesis significantly contributes to the practical applications of lipid-based nanomedicines.