A1-EP10-O18A is an asymmetric ionizable lipid developed by Starna Therapeutics for mRNA vaccine delivery. Synthesized via Michael addition between amine alcohols and acrylates, its optimized structure—combining a hydrophilic C10 chain and hydrophobic unsaturated C18 tail—enables pH-dependent ionization. As the core component of the STAR0225 lipid nanoparticle (LNP) platform, it efficiently encapsulates mRNA and facilitates endosomal escape. Preclinical studies demonstrate superior in vivo mRNA delivery (vs. commercial SM102 LNPs), with enhanced local biodistribution and minimal off-target accumulation. This lipid underpins STR-V003, an RSV prefusion F mRNA vaccine showing robust immunogenicity and protection in animal models, supporting its clinical transition (NCT06344975).
