Experimental study of podophyllotoxin dipalmitoylphosphatidylcholine liposome for topical skin application.

OBJECTIVE: To observe the drug release of podophyllotoxin liposome and the drug retention in the skin. METHODS: Two liposome suspensions containing respectively podophyllotoxin dipalmitoylphosphatidylcholine (DPPC) and soya bean lecithin were prepared ultrasonically. Podophyllotoxin anhydride and the liposome suspensions were applied onto the skin of young pigs to observe the drug retention in the skin at different time points in the following 2 days, with exclusive liposome or anhydride serving as control. RESULTS: One hour after application of podophyllotoxin anhydride, a peak of the drug concentration in the skin occurred followed by immediate declination, a process not observed after the application of bean lecithin liposome due to gradual drug release that produced drug concentration constantly much higher than that of podophyllotoxin anhydride. A peak concentration was also observed 4 h after application of podophyllotoxin DPPC liposome, which then declined slowly to and stabilized at a higher level than that of bean lecithin liposome of anhydride within 48 h. CONCLUSION: DPPC liposome-embedded podophyllotoxin better targets the drug to the skin after application, and is a suitable preparation for topical skin application.

[Effect of liposome on permeability and drug retention of sodium fluorescein in rat skin: an experimental study].

OBJECTIVE: To investigate the effect of liposome on the permeability and drug retention of sodium fluorescein(NaFl) in rat skin. METHODS: With an improved Franz diffusion cell and 0.125% NaFl liposome suspension as the model drug, in vitro measurement of percutaneous absorption and skin reservoir capacity for NaF1 was conducted using a fluorescence spectrophotometry at 4 and 12 h respectively after the diffusion experiment had started, and distribution of the fluorescence in rat skin was observed under fluorescence microscope at 4 h penetration experiment. NaFl solution of the same concentration as the model drugs served as the control for this experiment. RESULTS: In comparison with NaFl solution, liposomal NaFl suspension resulted in larger amount of NaFl retention in rat skin but smaller amount in the receiver cell in a four-hour Franz diffusion test, with also higher fluorescence intensity in the skin, especially the skin around the hair follicles. CONCLUSION: Local high drug concentrations can be achieved in the skin by liposomal suspension of water soluble drug for more effective treatment of skin diseases.

[Effects of podophyllotoxin solid lipid nanoparticles on proliferation and apoptosis of cervical carcinoma cells].

OBJECTIVE: To evaluate the anti-proliferative and apoptosis-inducing effect of podophyllotoxin solid lipid nanoparticles (PDP-SLN) in human cervical carcinoma cells in vitro. METHODS: Hela cells were treated with PDP and PDP-SLN at different concentrations (0.0005-5 micromol/L), and the proliferation of the cells was assessed using MTT assay and the apoptotic index was determined by flow cytometry. RESULTS: Both PDP and PDP-SLN showed obvious inhibitory effect on the cell proliferation in a dose- and time-dependent manner. At the same concentration, PDP-SLN produced stronger inhibitory effect on the cells than PDP, with IC50 24, 48, and 72 h after the cell exposure to PDP-SLN and PDP of 4.10, 0.65, 0.20 micromol/L and 9.2, 4.0, 1.3 micromol/L, respectively. Both PDP and PDP-SLN significantly induced the apoptosis of the Hela cell, and the apoptosis rates of the cells incubated in the presence of 0.5 micromol/L PDP-SLN reached 90.8% at 24 h and 94.2% at 72 h, significantly higher than the rate of cells incubated with PDP (64.1% at 24 h and 68.4% at 72 h, P<0.01). CONCLUSION: PDP-SLN can effectively suppress the proliferation and induce apoptosis of Hela cells in vitro.