Praziquantel-Solid Lipid Nanoparticles Produced by Supercritical Carbon Dioxide Extraction: Physicochemical Characterization, Release Profile, and Cytotoxicity.

Solid lipid nanoparticles (SLNs) can be produced by various methods, but most of them are difficult to scale up. Supercritical fluid (SCF) is an important tool to produce micro/nanoparticles with a narrow size distribution and high encapsulation efficiency. The aim of this work was to produce cetyl palmitate SLNs using SCF to be loaded with praziquantel (PZQ) as an insoluble model drug. The mean particle size (nm), polydispersity index (PdI), zeta potential, and encapsulation efficiency (EE) were determined on the freshly prepared samples, which were also subject of Differential Scanning Calorimetry (DSC), Fourier-Transform Infrared Spectroscopy (FTIR), drug release profile, and in vitro cytotoxicity analyses. PZQ-SLN exhibited a mean size of ~25 nm, PdI ~ 0.5, zeta potential ~-28 mV, and EE 88.37%. The DSC analysis demonstrated that SCF reduced the crystallinity of cetyl palmitate and favored the loading of PZQ into the lipid matrices. No chemical interaction between the PZQ and cetyl palmitate was revealed by FTIR analysis, while the release or PZQ from SLN followed the Weibull model. PZQ-SLN showed low cytotoxicity against fibroblasts cell lines. This study demonstrates that SCF may be a suitable scale-up procedure for the production of SLN, which have shown to be an appropriate carrier for PZQ.

Toxicology of 3-epi-deoxynivalenol, a deoxynivalenol-transformation product by Devosia mutans 17-2-E-8.

Microbial detoxification of deoxynivalenol (DON) represents a new approach to treating DON-contaminated grains. A bacterium Devosia mutans 17-2-E-8 was capable of completely transforming DON into a major product 3-epi-DON and a minor product 3-keto-DON. Evaluation of toxicities of these DON-transformation products is an important part of hazard characterization prior to commercialization of the biotransformation application. Cytotoxicities of the products were demonstrated by two assays: a MTT bioassay assessing cell viability and a BrdU assay assessing DNA synthesis. Compared with DON, the IC50 values of 3-epi-DON and 3-keto-DON were respectively 357 and 3.03 times higher in the MTT bioassay, and were respectively 1181 and 4.54 times higher in the BrdU bioassay. Toxicological effects of 14-day oral exposure of the B6C3F1 mouse to DON and 3-epi-DON were also investigated. Overall, there were no differences between the control (free of toxin) and the 25 mg/kg bw/day or 100 mg/kg bw/day 3-epi-DON treatments in body and organ weights, hematology and organ histopathology. However, in mice exposed to DON (2 mg/kg bw/day), white blood cell numbers and serum immunoglobulin levels were altered relative to controls, and lesions were observed in adrenals, thymus, stomach, spleen and colon. Taken together, in vitro and in vivo studies indicate that 3-epi-DON is substantially less toxic than DON.

THE ESTABLISHMENT OF THE NORMAL HUMAN FIBROBLAST CELL LINE AND A STUDY OF ITS BIOLOGICAL CHARACTERIZATION / 第二军医大学学报

The normal human fibroblast cell line (NHF8) derivd from normal adult foreskin was passaged successfully in cell culture for more than 400 days.The cells were fibro-blast-like and were grown in the cell culture media NO.I with 15% newborn calf serum and were subcultured by trypsinization at a 1 : 2 split ratio. The cell line had a log phase doubling time of 26 h and its growth curve appeared in "s" shape. The mode of the chromosomes of the cell line was 46 and its frequency of sister-chroma -tid exchange (SCE), induced by UV irradiation or [not, was 0.143/per chromosome and 0.144/per chromosome respectively. The level of UV-induced unscheduled DNA synthesis (UDS) was also normal. The results demonstrate that the cell line is normal human diploid fibroblast cell line with normal function of excision repair of DNA damage and can be used as control cells in many studies.