Ionizable lipids and nanoparticles comprising same

A lipid nanoparticle comprising a compound, a salt of said compound or both, wherein the compound is represented by Formula 1:

• wherein:
• each X independently represents a —O—, —S—, CH2, or X is absent;
• each Z independently represents —OH or —SH;
• each A independently represents O or S;
• each n is independently between 0 and 5, and at least one n is not 0;
• each R independently is H, or comprises an optionally substituted C5-C30 alkyl;
• wherein said lipid nanoparticle further comprising an active agent, a helper lipid, a structural lipid and a modified lipid wherein:
• the helper lipid is a cationic lipid;
• a ratio of said compound relative to a total lipid content of said lipid nanoparticle is between 10 and 50 mol %;
• and
• a ratio of said structural lipid relative to said total lipid content of said lipid nanoparticle is between 5 and 50 mol %;
• and wherein said lipid nanoparticle is characterized by an average zeta potential in a range between −5 and +40 mV at a pH between 6 and 8.