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The aim of the study was to develop a self-emulsifying drug delivery systems (SEDDS) comprising chlorhexidine (CX) and monododecylamide-EDTA (alkyl-EDTA) exhibiting enhanced microbicidal properties. SEDDS containing 20% Captex 300, 45% Cremophor EL, 17% Tween 80 and 18% DMSO were loaded with 3% (m/v) alkyl-EDTA (FA) and formulations of 1% CX and 1.5% (m/v) alkyl-EDTA (FA-CX1% and FA-ED1.5%) were prepared separately as well as in combination (FA-CX1%ED1.5%). Resazurin assay was performed to assess the biocompatibility of SEDDS in concentrations of 0.5% and 1%. Alkyl-EDTA SEDDS were also evaluated for their binding affinity towards Ca2+ and Mg2+ as well as for augmented antimicrobial properties using E. coli as model germ. Biocompatibility assay of SEDDS revealed that >85% of cells remained viable after 4 h. SEDDS FA efficiently bound 770 ± 19 μmol/g of calcium and 784 ± 16 μmol/g of magnesium, respectively. SEDDS FA-CX1%ED1.5% showed a 34.3- and 12.9-fold enhanced antimicrobial effect compared to FA-ED1.5% and FA-CX1%, respectively. The combination of CX with alkyl-EDTA in SEDDS seems therefore to be a promising strategy to enhance the antimicrobial activity of this antiseptic drug.

We describe in this paper a general method for synthesizing a new class of nanocomposites with a nanoscale metal-organic framework (NMOF) core and a silica shell. Silica shells of variable thickness were deposited on the NMOFs that had been surface-modified with polyvinylpyrrolidone (PVP) using a sol-gel procedure. The NMOF core of the nanocomposite could be completely removed (via dissolution) at low pH to afford hollow silica shells with varied thickness and aspect ratios. We also showed that the silica shell of such nanocomposites significantly stabilized the NMOF core against dissolution, thus demonstrating the ability to control the release of metal constituents from such silica-coated NMOFs. The silica shell was further functionalized with a silylated Tb-EDTA monoamide derivative for the luminescence sensing of dipicolinic acid (DPA), which is a major constituent of many pathogenic spore-forming bacteria. Owing to the tunability of NMOF composition and morphology, the present approach should allow for the synthesis of not only interesting nanoshells that are not accessible with presently available templates but also novel core-shell hybrid nanostructures for future imaging, sensing, and drug delivery applications. Copyright

Eight novel diamino-ester ligands were synthesized by amidation reaction of long-chain alkyl esters of l-lysine with diethylenetriamine pentaacetic acid monoanhydride or ethylenediamine tetraacetic acid monoanhydride. The corresponding dimeric Gd(iii) complexes were obtained by treating these ligands with GdCl3?6H2O. All ligands and complexes were characterized by 1H NMR, FT-IR, and elemental analysis. The longitudinal relaxation time (T1) was measured, and all relaxivity values (R1) of these dimeric Gd(iii) complexes are higher than that of Magnivest (Gd-DTPA). One of these complexes, possessing the highest relaxivity in the DTPA series, was chosen to test the acute toxicity and T 1-weighted imaging. It was found that this dimeric Gd(iii) complex exhibits no acute toxicity, and offers highly enhanced MRI signal and increases intention time in the rat liver tissue compared to Magnivest. CSIRO 2007.

The synthesis and structural characterization of the vitamin B12 derivatives 9 and 10 equipped with a peripheral EDTA (ethylenediaminetetraacetic acid) binding site is described. It is based on the condensation of an activated ester of cobester-c-acid with ethane-1,2-diamine or 2-aminoethanol followed by acylation of the resulting amines with the monoanhydride 8 of EDTA. The title compounds 9 and 10 can be used as modifiers for metal oxide semiconductor electrodes and are potential precursors for the synthesis of bimetallic, supramolecular catalysts.

The syntheses of two cyclomaltoheptaose-based metal chelants, cyclomaltoheptaose-ethylenediaminetetraacetate (CD-EDTA) and cyclomaltoheptaose-diamide-disulfur (CD-DADS), are described. The chelant moieties are attached to the 6-position of a single pyranose in the cyclomaltoheptaose via a short diamine spacer chain. Characterization of these novel chelants has been achieved using NMR and MS techniques. The peculiar fluxional properties of the CD-EDTA molecules is also discussed.

Spin labeled EDTA, CDTA and DTPA chelating agents and their gadolinium complexes were synthesized and evaluated for their effects on the spin-lattice (T1) and spin-spin (T2) relaxation times of water, plasma, and blood.It was found that the spin labeled chelating agents are effective proton relaxation agents.Although, the gadolinium complexes of these agents have superior relaxation properties, the differences in relaxivity between the spin labeled complexes and the non-spin labeled gadolinium complexes are marginal.The spin labeled agents and their gadolinium complexes are expected to be very useful in designing paramagnetic conjugates with biomolecules.In particular, the latter type possesses high proton relaxivity combined with a nitroxyl marker which can be followed pharmacokinetically by EPR. - Keywords: NMR Imaging, Contrast Agents, Nitroxyl, Gadolinium, Relaxation Times