Nosiheptide is a lipophilic peptide of significant anti-hepatitis B virus (anti-HBV) activity in cell culture, but has poor distribution to liver in vivo. In this study, recombinant high-density lipoprotein (rHDL) complexes of nosiheptide were constructed to target this anti-HBV agent to hepatocytes. The optimized rHDL-nosiheptide complex had a high drug-loading efficiency (>80%) and a diameter smaller than 30 nm. The concentration of nosiheptide in an optimized rHDL-nosiheptide complex to achieve 50% virus inhibition (IC(50)) in HepG(2) 2.2.15 cells was 0.63 microg/ml, which was 40 times lower than the IC(50) of nosiheptide in control liposome (2.5 microg/ml) and 200 times lower than the IC(50) of the free nosiheptide (12.5 microg/ml). The complex targeted most of the administered nosiheptide to the liver within 30 min after i.v. injection to male Wistar rats. Together, this report provides early evidence that it is feasible to develop efficient, HDL-based drug delivery systems against HBV, utilizing apolipoprotein A-I as the targeting moiety.