In vitro targeting effect of lactoferrin modified PEGylated liposomes for hepatoma cells / 药学学报

A lactoferrin-containing PEGylated liposome system (Lf-PLS) was developed and tested in vitro as a hepatoma-targeting drug delivery system. PEGylated liposomes (PLS) were successfully prepared using the thin film hydration method with peglipid post insertion. Lf was covalently conjugated onto the carboxyl terminal of DSPE-PEG2000-COOH on liposomes. Coumarin-6 was used to trace Lf-PLS with fluorescence. The cellular uptake of this system was carried out in asialoglycoprotein receptor (ASGPR) positive HepG2 cells via confocal microscopy and flow cytometry. The Lf-PLS liposome was observed as spherical or oval vesicles with the particle size around 130 nm, zeta potential about -30 mV and encapsulation efficiency more than 80%. The confocal microscopy images and flow cytometry data demonstrated that Lf-PLS resulted in significantly higher cell association by ASGPR positive HepG2 cells compared to PLS. The association between Lf-PLS and cells were dependent on the concentration, time and temperature, which was inhibited by pre-incubation with excessive free Lf. The results suggest that Lf-PLS has a good targeting effect on HepG2 cells in vitro. The targeting mechanism may be related to the specific binding of Lf and ASGPR on HepG2 cells, which guides Lf-PLS to the cell surface to induce an active endocytosis process. All these results demonstrated that Lf-PLS might be a potential drug delivery system in targeting hepatocellular carcinoma, which deserves more research on its targeting ability, antitumor efficiency, and metabolism in vivo for treatment of hepatomacellular carcinoma.

In vitro study of transdermal penetration and iontophoresis of hepatitis B vaccines through rat skin / 药学学报

In vitro percutaneous delivery of hepatitis B vaccines was investigated in order to assess the penetration of vaccine under passive diffusion and iontophoresis conditions. The study was carried out using Franz vertical diffusion cell through the hairless abdominal skin of Sprague-Dawley (SD) rats. Enzyme-linked immunosorbent assay (ELISA) was used to determine the cumulative amount of permeation and the retention amount of drug in skin. Passive diffusion alone resulted in less skin permeation and retention of hepatitis B vaccines, only (2.1 +/- 0.1) ng x cm(-2) and (2.3 +/- 0.1) ng x cm(-2) after 24 h when the initial concentration of vaccine in the donor compartment was 23 microg x mL(-1) and 46 microg x mL(-1), respectively. After removing the stratum corneum, the permeation and retention amount of hepatitis B vaccines increased to (383.7 +/- 86.2) ng x cm(-2) and (16.8 +/- 4.6) ng x cm(-2), respectively, 171.6-folds and 2.1-folds more than that from its intact skin with the drug loaded at 46 microg x mL(-1). Iontophoresis induced a significant increase of cumulative and retention amount of hepatitis B vaccines through the skin (P < 0.05). Application of iontophoresis significantly enhanced the permeation of hepatitis B vaccines (P < 0.05) by 2.7-folds and 6.6-folds for the intact skin, and by 1.6-folds and 1.8-folds for the tape-stripped skin with initial drug loading of 23 microg x mL(-1) and 46 microg x mL(-1), respectively. Iontophoresis also significantly increased the amount of drug retained in the skin. After applying iontophoresis for 6 h, the amount of skin retention was nearly the same as passive diffusion for 24 h both from intact skin [(16.8 +/- 4.6) ng x cm(-2) vs (13.3 +/- 5.4) ng x cm(-2)] (P > 0.05) and tape-stripped skin [(36.7 +/- 14.1) ng x cm(-2) vs (26.8 +/- 11.2) ng x cm(-2)] (P > 0.05). Overall, these findings revealed that the transportation efficiency of bioactive substance like hepatitis B vaccines may be improved by iontophoresis, which can be potentially used in the field of transcutaneous immunization.