ABSTRACT
The hydroxycamptothecin (HCPT) PEGylated liposomes (HCPT-LP) were modified with RGD cyclopeptide formed the tumor-targeting liposomes (HCPT-RGD-LP). HCPT-LP and HCPT-RGD-LP were injected intravenously with single dose of 5 mg x kg(-1) to rats. The drug concentration in plasma was determined and the pharmacokinetic behaviour was compared. The HCPT distribution in heart, liver, spleen, lung, kidney and plasma of mice was investigated following intravenous administration of HCPT-LP and HCPT injection. The nude mice implanted human hepatoma HepG2 cells were studied by in vivo imaging. The fluorescent probe was DiR and the nude mice were injected with DiR PEGylated liposomes (DiR-LP) and DiR-LP modified with RGD cyclopeptide (DiR-RGD-LP). The results showed that there was no significant difference (P > 0.05) of main pharmacokinetic parameters t1/2beta, CL, V(c), AUC(0-48 h), AUC(0-inifinity), MRT(0-48 h), MRT(0-infinity) between HCPT-RGD-LP and HCPT-LP. HCPT-LP had a remarkably better long-circulating effect than HCPT injection in mice and the concentration of HCPT was highest in liver. The DiR accumulation in tumors of DiR-RGD-LP was higher than that of DiR-LP by the visualized fluorescence of in vivo imaging. It indicated that such PEGylated liposomes modified with RGD cyclopeptide could improve the tumor targeting efficacy.
Subject(s)
Animals , Female , Humans , Male , Mice , Rats , Area Under Curve , Camptothecin , Chemistry , Pharmacokinetics , Diagnostic Imaging , Drug Delivery Systems , Fluorescent Dyes , Hep G2 Cells , Liposomes , Chemistry , Pharmacokinetics , Liver Neoplasms , Diagnosis , Mice, Inbred BALB C , Mice, Nude , Neoplasm Transplantation , Oligopeptides , Chemistry , Pharmacokinetics , Polyethylene Glycols , Chemistry , Pharmacokinetics , Random Allocation , Rats, Sprague-Dawley , Spectroscopy, Near-Infrared , Tissue DistributionABSTRACT
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.