[In vitro targeting effect of lactoferrin modified PEGylated liposomes for hepatoma cells].

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 vivo imaging in tumor-bearing animals and pharmacokinetics of PEGylated liposomes modified with RGD cyclopeptide].

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.

[Optimization of ligustrazine phosphate thermosensitive gel formulation by central composite design-response surface methodology].

OBJECTIVE: To optimize the formulation of ligustrazine phosphate thermosensitive gel by the central composite design-response surface methodology (RSM plus CCD). METHODS: In the formulation design using RSM plus CCD, independent variables were the amounts of poloxamer 407 and poloxamer 188, and gel temperature was dependent variable. Multilinear and quadratic models were used to estimate the relationship between the dependent and the independent variables, select the optimal formulations and validate. RESULTS: The quantitative relationships between two factors and evaluation index were characterized, quadratic model had better prediction capability than multilinear model. CONCLUSION: Quadratic model is performed in the optimization of formulation due to the statistical confidence. The optimization of ligustrazine phosphate thermosensitive gel formulation can be achieved by the central composite design and response surface methodology.

[Preparation of docetaxel liposomes and their pharmacokinetics in rabbits].

BACKGROUND & OBJECTIVE: Docetaxel is used to treat non-small cell lung cancer, breast cancer and ovarian cancer. It is indissolvable and the solvent containing polysorbate-80 and 13% solution of ethanol is used for injections. Its clinical application is limited because of frequent severe hypersensitive responses. This study was to prepare docetaxel (DOC) liposomes and investigate their pharmacokinetics in rabbits after intravenous administration. METHODS: DOC liposomes, with or without modification of polyethylene glycol (PEG), were prepared by thin-film ultrasonic dispersion method. The entrapment efficiency and mean diameter of the liposomes were measured. After intravenous administration in rabbits, plasma DOC concentration was detected by solid phase extraction high-performance liquid chromatography (SPE-HPLC). The pharmacokinetic parameters were calculated and analyzed by 3p87 pharmacokinetic program. RESULTS: The entrapment efficiency of DOC liposomes was above 75%. The mean diameter was about 150 nm. The half-life of distribution (T(1/2alpha)) were (0.17+/-0.04) h for market docetaxel injection (M-DOC), (0.31+/-0.11) h for common DOC liposome (L-DOC), and (0.32+/-0.06) h for PEG-2000-modified DOC long circulating liposome (PEG-DOC-LCL); the half-life of clearance (T(1/2beta)) were (8.54+/-1.05), (11.18+/-1.33), and (10.51+/-1.13) h, respectively; the apparent volume of distribution (V(d)) were (13.66+/-3.62), (8.65+/-1.11), and (6.31+/-0.55) L, respectively; the area under the concentration-time curve from 0 to 24 h (AUC(0-->24)) were (13.45+/-2.44), (22.83+/-3.57), and (29.31+/-5.96) mg x (h x L)(-1), respectively; the area under the concentration-time curve from 0 to infinity h (AUC(0-->infinity)) were (15.07+/-2.76), (28.70+/-4.95), and (36.95+/-9.13) mg x (h x L)(-1), respectively; the clearance (CL) were (1.10+/-0.18), (0.54+/-0.08), and (0.42+/-0.07) L/h, respectively. CONCLUSION: The thin-film prepared DOC liposomes have high entrapment efficiency and small particle size. Both liposomes, especially PEG-DOC-LCL, can raise AUC and prolong the resident time of drugs in the blood circulating system.