503O13

503O13 is a next-generation, biodegradable lipid nanoparticle (LNP) engineered for highly efficient and targeted siRNA delivery. Designed through rational structure-activity criteria—including optimal tail length (O13), tertiary amines, and a surface pKa ≥5.5—this single-component LNP achieves unparalleled gene silencing with an ultra-low EC50 of 0.01 mg/kg in preclinical models.503O13 outperforms non-degradable counterparts (e.g., C12-200) with improved toxicity profiles—no hepatic necrosis or pancreatic inflammation—while maintaining rapid blood clearance (t1/2: 6 min) and organ-specific accumulation (liver/spleen).