This study investigated the pharmacokinetic profile and biodistribution of HB-110, a novel HBV therapeutic vaccine candidate, in mice. HB-110 was rapidly degraded in the blood after i.v.injection with a half-life of 1.9${pm}$0.083 min, and was no longer detected at 60 min except in one individual near the detection limit. In the i.m. injection, plasmid DNA was detectable at the injection site until ff days after administration, but the amounts were just above the detection limit. The blood concentration of HB-110 showed a maximum of 604 pg/mL at 15 min after i.m.injection, which was followed by degradation to undetectable levels at 90 min. The plasmid DNA in tissues peaked at 90 min after administration. The highest concentration of plasmid DNA was detected in the liver (24.172 pg/mg tissue), and considerable amounts were also observed in the lung (9.467 pg/mg tissue) and spleen (7.688 pg/mg tissue). The amount of plasmid DNA in tissues was 2 to 3 orders of magnitude lower than in the injection site at the same time points. The HB-110 concentration in tissues, including gonads, decreased rapidly and was undetectable 24 h after administration.