Self-assembled nanoparticles of cholesterol-conjugated carboxymethyl curdlan as a novel carrier of epirubicin.

The purpose of this study was to develop nanoparticles made of cholesterol-conjugated carboxymethyl curdlan (CCMC) entrapping epirubicin (EPB) and establish their in vitro and in vivo potential. CCMC was synthesized and characterized by Fourier transform infrared spectra (FT-IR) and proton nuclear magnetic resonance spectra ((1)H NMR). The degrees of substitution (DS) of the cholesterol moiety were 2.3, 3.5 and 6.4, respectively. EPB-loaded CCMC-3.5 nanoparticles were prepared by the remote loading method. The physicochemical characteristics, drug loading efficiency and drug release kinetics of EPB-loaded CCMC-3.5 nanoparticles were characterized. The in vitro release profiles revealed that EPB release was sensitive to the pH as well as the drug loading contents. The cellular cytotoxicity and cellular uptake were accessed by using human cervical carcinoma (HeLa) cells. The EPB-loaded CCMC-3.5 nanoparticles were found to be more cytotoxic and have a broader distribution within the cells than the free EPB. The in vivo pharmacokinetics and biodistribution were investigated after intravenous injection in rats. Promisingly, a 4.0-fold increase in the mean residence time (MRT), a 4.31-fold increase in the half-life time and a 6.69-fold increase in the area under the curve (AUC 0-->infinity) of EPB were achieved for the EPB-loaded CCMC-3.5 self-assembled nanoparticles compared with the free EPB. The drug level was significantly increased in liver at 24 and 72 h; however, it decreased in heart at 8 and 24 h compared with the free EPB. The in vivo anti-tumor study indicated that the EPB-loaded CCMC-3.5 self-assembled nanoparticles showed greater anti-tumor efficacy than the free EPB. Taken together, the novel CCMC self-assembled nanoparticles might have potential application as anti-cancer drug carriers in a drug delivery system due to good results in vitro and in vivo.

[AF + BAF for treating effluent in the sewage plant of the resin and chemical industry park].

The anaerobic filter (AF) and biological aerated filter (BAF) were employed to treat the effluent in a sewage plant of the resin and chemical industry park. The ceramsite was used in BAF. In this study, the influent COD was 200-300 mg x L(-1) and the pilot model scale was 2-4 L x d(-1). According to the results, the AF-BAF treatment had a good effect on organic wastewater. When the AF HRT was 24 h and BAF was 12 h, the removal of COD reached 73.4%, and that of NH4(+)-N reached 93.8%. From gas chromatography-mass spectrometry (GC-MS) and three-dimensional fluorescence analysis, it was found that small organic molecules and microbial metabolites could be removed effectively. However, there was no obviously effect on the removal of saturated alkane and nitrogenous heterocyclic compounds. From the denature gradient gel electrophoresis (DGGE) spectra analysis, it was shown that there were more kinds of microorganism in the sludge of the AF than in the up-flow anaerobic sludge bed (UASB), which indicates that the AF-BAF system is more effective on treating effluent in a sewage plant of the resin and chemical industry park.