Promising gene delivery system based on polyethylenimine-modified silica nanoparticles.

This article reports on the synthesis and full characterization of innovative silica-based nanoparticle composed of fumed silica as a core decorated with polyethylenimine (PEI) with different molecular weights (25, 10 and 1.8 kDa). Wide range of analytical, spectroscopic, and microscopic methods (TEM, DLS, ζ potential, elemental analysis (EA), TNBS and FTIR) were used to characterize the nanoparticles. Furthermore, transfection efficiency of these nanoparticles as non-viral vector was examined. The silica-PEI conjugates retained both the ability of PEI to fully condense plasmid DNA at low N/P ratios and suitable buffering capacity at the endosomal pH range. PEI-functionalized silica remarkably enhanced EGFP-N1 gene expression in murine neuroblastoma (Neuro-2A) cells up to 38 folds compared to PEI 25 kDa. Meanwhile the results of the cytotoxicity assays indicated that these silica-PEI conjugates have acceptable level of viability.

3-Ethyl-sulfanyl-5-methyl-1-phenyl-7-(pyrrolidin-1-yl)-1H-pyrimido[4,5-e][1,3,4]thia-diazine.

In the crystal structure of the title compound, C(18)H(21)N(5)S(2), the thia-diazine six-membered ring and pyrrolidine five-membered ring display boat and envelope conformations, respectively. The crystal structure contains weak C-H⋯N and C-H⋯S hydrogen bonding.

Design and synthesis of pyrimido[4,5-b][1,4]benzothiazine derivatives, as potent 15-lipoxygenase inhibitors.

A group of 2-substituted pyrimido[4,5-b][1,4]benzothiazines were designed, synthesized, and evaluated as potential inhibitors of 15-lipoxygenase (15-LO). Compounds 4d and 4e showed the best IC50 of 15-LO inhibition (IC50=18 and 34 microM, respectively). All compounds were docked into 15-LO. As a result the sulfur atom was oriented toward the iron atom of the active site of 15-LO. We suggest the interaction of the iron atom is essential for the activity of the inhibitors.