Résumé
ABSTRACT The present study reports a promising antioxidant protection by a recently developed micellar propolis formulation, against oxidative stress in in vitro and in vivo models of toxicity. The formulation, based on poplar propolis encapsulated in poly(ethylene oxide)-β-poly(propylene oxide)-β-poly(ethylene oxide) triblock copolymer (PEO26-PPO40-PEO26) micelles is characterized by small size (D h = 20 nm), enhances aqueous solubility and good colloidal stability. In vitro, propolis-loaded PEO26-PPO40-PEO26 micelles (20-100 µg/ml) significantly increased the cell viability of human hepatoma HepG2 cells, subjected to H2O2-induced cell injury (0.1 mM, 1 h). Antioxidant activity and protection of the micellar propolis were evaluated in a model of carbon tetrachloride-induced hepatotoxicity in rats (10% CCl4 solution, 1.25 ml/kg, p.o.) by measurement of non-enzyme (malondialdehyde and glutathione) and enzyme (catalase and superoxide dismutase) biomarkers of oxidative stress. Clinic observations, hematological, biochemical parameters and histological analysis were also performed. In vivo, micellar propolis (20 mg/kg b.w., p.o., 14 days) ameliorated CCl4-induced acute liver injury in rats. The oral administration of micellar propolis significantly prevented serum transaminase increases, as well as brought the levels of malondialdehyde, glutathione, and antioxidant enzymes catalase and superoxide dismutase toward the controls levels. Therefore, PEO26-PPO40-PEO26 micelles could be considered as a promising oral delivery system of propolis against oxidative stress injury in liver cells.
Résumé
Due to the advantages of polymer micelles and the anticancer activity of doxorubicin (DOX), the polymer micelle of DOX is expected to be used for drug delivery in anticancer applications. As a biocompatible and biodegradable polymer, amphiphilic copolymer heparosan-adipic dihydrazide-vitamin E succinate (KV) can be self-assembled to form micelles with core-shell structure in aqueous phase. In this article, KV conjugates with two different degrees of substitution (DS) were synthesized to load DOX and were characterized by 1H NMR. The size distribution, morphology, zeta potential and release behavior in vitro of the DOX-loaded micelles were studied. In vitro cytotoxicity was investigated by MTT assay against MGC80-3 and COS7 cells. The cellular uptake of the DOX-loaded micelles was observed by fluorescence microscopy and flow cytometry. The 1H NMR spectra results confirmed the KV polymers were successfully conjugated and the degree of VES grafted on heparosan polysaccharide were 12% and 25%. Briefly, the micelles with two different DS were expressed as KV12 and KV25. The DOX-loaded micelles could resist serum adsorption because of the negative charge on the surface. The average particle size measured by dynamic light scattering (DLS) method was 140-150 nm and the TEM results indicated that the morphology of DOX-loaded micelles were spherical. The encapsulation efficiency and drug loading were 80% and 10%-15%, respectively. The DOX-loaded micelles had sustained release behavior and the cumulative release of DOX/KV12 was slightly higher than DOX/KV25. Moreover, the viabilities of cells which were co-incubated with blank micelles were greater than 90%. It is clear that the blank micelles almost non-toxic to both cells. The IC50 of drug-loaded micelles against COS7 cells was much higher than that of MGC80-3 cells and the DOX/KV12 exhibited greater cytotoxicity. The cellular uptake of DOX/KV on MGC80-3 was greater than COS7 cells. In this study, KV polymer micelles have a sustained drug release activity and have a good selectivity to tumor cells, so it would be a potential carrier in drug delivery.
Résumé
@#Paclitaxel(PTX), an effective anti-tumor drugs, is water-insoluble. And Cremophor as a solubilizer in its commercial formulation, Taxol® , often causes side-effects which limit its antitumor effect. We designed and synthesized PEGylated carboxymethyl chitosan-rhein(CRmP)conjugate, and further prepared PTX-loaded CRmP polymeric micelles(PTX/CRmP). CRmP conjugate was characterized by fourier transform infrared spectrum(FT-IR)and nuclear magnetic resonance spectroscopy(1H NMR). The particle size and surface morphology of PTX/CRmP were characterized by dynamic laser particle size analyzer(DLS)and atomic force microscope(AFM), respectively. The cytotoxicity of CRmP conjugate and PTX/CRmP against MCF-7 cells were evaluated by MTT assay. The results showed that CRmP conjugates displayed very low cytotoxicity and that PTX/CRmP exhibited better in vitro anti-tumor activity than Taxol® at the same drug concentration after a long-term administration.
Résumé
With the increasing number of food safety problems caused by the abusing and misusing of plant hormones, it will be increasingly important to strengthen the trace detection of plant hormones in foods. In this study, benzyl methacrylate_methyl methacrylate_based amphiphilic polymer micelles were prepared, and a method for trace determination of five plant hormones was established by using these micelles. This method was rapid, sensitive and reproducible. Through optimization, the best experimental conditions were obtained as follows: 2 g/L polymer micelles, 50 mmol/L NaOH_H3BO3 buffer (pH 9. 2), 15 kV running voltage. Based on this novel method, naphthalene acetic acid in the solution of rooting powder was determined.
Résumé
facile and reliable method to perform pilot pharmacokinetic (PK) and biodistribution studies is necessary for expediting the overall development and clinical translation of novel nanoparticle drug carriers. In this study, we compared two common analytical techniques, fluorescence spectrometry using a microplate reader and liquid chromatography/mass spectrometry (LC/MS), demonstrating the quantification of a model anticancer drug (doxorubicin: DOX) in its free drug and nanoparticle formulations in vivo. Drug-loaded nanoparticle formulations were prepared from poly(ethylene glycol)-poly(aspartate) block copolymers, which formed two model drug carriers with different particle stability, self-assembled polymer micelles (DOX-micelles) and cross-linked nanoassemblies (DOX-CNAs). These three DOX formulations were injected into tumor-bearing mice at a DOX equivalent concentration. DOX levels in liver, spleen, and tumors were found to be comparable regardless of the analytical methods. LC/MS showed lower serum level than spectrometry with a microplate reader, which is consistent with the fact that DOX metabolites are present mainly in the serum.These results demonstrate that, in comparison to the LC/MS method, spectrometry using a microplate reader would be a viable and more facile method to perform pilot PK and biodistribution studies of various potential nanoparticle drug carriers using DOX as a model drug.