ATX100 is a biodegradable ionizable lipid with improved in vivo activities for siRNA delivery via lipid nanoparticles (LNP). The physicochemical parameters of ATX100: pKa 6.316 lipophilicity cLogD 14.03 nanoparticle size 82 nm. The in vivo factor VII knockdown efficiency of ATX100 is 97% (0.03mg/kg in mice i.v.).