[The distribution of azidothymidine palmitate galactosylated liposomes in mice]

Hepatocytes act as a reservoir for the human immunodeficiency viruses (HIV) and are responsible for its continual dissemination in the peripheral circulation. For this reason, galactosylated liposomes (GalLs) containing home-made [(2-lactoylamido) ethylamino] formic acid cholesterol ester (CH-ED-LA ) as a homing device were prepared to study the biodistribution of the liposomal azidothymidine palmitate (AZTP) in mice. Four liposomes of the present study, soybean phosphatidylcholine (SPC)/cholesterol(CH)/CH-ED-LA (80 : 10: 10, 10% GalLs), SPC/CH/CH-ED-LA (80 : 15:5, 5% GalLs), SPC/CH/CH-ED-LA (80 : 17 : 3, 3% GallLs) and SPC/CH (80 : 20, CL) incorporated AZTP were prepared by ethanol-injection method followed by ultrasonic-dispersion and characterized by entrapped efficiency which was more than 95% and their mean diameter was less than 100 nm, respectively. The effects of the addition upon the liposomal membrane potential and AZTP content were also unseen. The distributions of AZT in various organs were determinated by reversed phase HPLC after intravenous administration via tail vein in mice, at a dose of 15.85 mg x kg(-1) AZT solution and 30 mg x kg(-1) AZTP (at equimolar doses) in CL or GalLs, respectively. Compared to AZT control solution, the half-life of AZT in each group of AZTP liposomes increased significantly (P < 0.05). In addition, the concentration-averaged overall drug targeting efficiency (r(e)) of the liver presented by AZTP CL and GalLs containing 3% , 5% , 10% (mol/mol) CH-ED-LA increased 1.32 and 1.48, 2.13, 1.50 times as that of AZT solution, respectively. These results indicate that liposomes containing such novel galactosylated lipid, CH-ED-LA, had remarkably improved the targetability of AZTP to liver, and are anticipated to be a potential candidate for liver targeting delivery carriers.