Silver Nanoparticles Stabilized with Phosphorus-Containing Heterocyclic Surfactants: Synthesis, Physico-Chemical Properties, and Biological Activity Determination.

Phosphorus-containing heterocyclic cationic surfactants alkyldimethylphenylphospholium bromides with the alkyl chain length 14 to 18 carbon atoms were used for the stabilization of silver nanodispersions. Zeta potential of silver nanodispersions ranges from +35 to +70 mV, which indicates the formation of stable silver nanoparticles (AgNPs). Long-chain heptadecyl and octadecyl homologs of the surfactants series provided the most intensive stabilizing effect to AgNPs, resulting in high positive zeta potential values and smaller diameter of AgNPs in the range 50-60 nm.

Biological Activities and ADMET-Related Properties of Novel Set of Cinnamanilides.

A series of nineteen novel ring-substituted -arylcinnamanilides was synthesized and characterized. All investigated compounds were tested against as the reference strain, two clinical isolates of methicillin-resistant (MRSA), and . (2)--[3-Fluoro-4-(trifluoromethyl)phenyl]-3-phenylprop-2-enamide showed even better activity (minimum inhibitory concentration (MIC) 25.

Synthesis, physicochemical properties and biological activities of novel alkylphosphocholines with foscarnet moiety.

A series of alkylphosphocholines with foscarnet moiety was synthesized. The structure of these zwitterionic amphiphiles was modified in both polar and non-polar parts of surfactant molecule. Investigations of physicochemical properties are represented by the determination of critical micelle concentration, the surface tension value at the cmc and the surface area per surfactant head group utilising surface tension measurements.

Small dense LDL - an important part of the atherogenic lipoprotein profile in individuals with impaired metabolism of lipoproteins. Comparison of two analytical procedures.

Objectives: To compare two different analytical methods for determination of small dense LDL and to determine a share of corresponding and non-corresponding (inconsistent) results METHODS: In the group of 104 hyperlipidemic patients and 20 healthy individuals of the control group we analysed the total cholesterol and triglycerides by enzymatic CHOD PAP method (Roche Diagnostics, Germany) in EDTA-K2 plasma. Small dense LDL (sdLDL) were quantified by the electrophoretic method for lipoprotein analysis on polyacrylamide gel (PAG) (Lipoprint LDL System, Quantimetrix, CA, USA) and simultaneously, the small dense LDL concentrations in the indentical samples were analysed by an enzymatic method LDL-EX ´Seiken´(Randox, England).

Results: In 31 patients we found the discrepancy in the sdLDL levels using the two different procedures.

Investigation of Anti-Inflammatory Potential of -Arylcinnamamide Derivatives.

A series of sixteen ring-substituted -arylcinnamanilides, previously described as highly antimicrobially effective against a wide spectrum of bacteria and fungi, together with two new derivatives from this group were prepared and characterized. Moreover, the molecular structure of (2)--(2-bromo-5-fluorophenyl)-3-phenylprop-2-enamide as a model compound was determined using single-crystal X-ray analysis. All the compounds were tested for their anti-inflammatory potential, and most tested compounds significantly attenuated the lipopolysaccharide-induced NF-κB activation and were more potent than the parental cinnamic acid.

The Synthesis, Self-Assembled Structures, and Microbicidal Activity of Cationic Gemini Surfactants with Branched Tridecyl Chains.

Cationic gemini surfactants with polymethylene spacer and linear alkyl chains containing an even number of carbon atoms have been extensively studied in the recent past, with the emphasis put on the determination of their aggregation behaviour in aqueous solution and their biological properties. However, the information on the aggregation of branched gemini surfactants with an odd number of carbon atoms in their alkyl chains is only sparsely reported in the literature. To help cover this gap in the research of cationic gemini surfactants, a series of branched bisammonium cationic gemini surfactants with an odd number of carbon atoms in alkyl chains (tridecane-2-yl chains) and a polymethylene spacer with a variable length ranging from 3 to 12 carbon atoms have been synthesized and investigated.

pH-Sensitive ,Dimethylalkane-1-amine -Oxides in DNA Delivery: From Structure to Transfection Efficiency.

pH-sensitive liposomes composed of homologues of series of ,-dimethylalkane-1-amine -oxides (CNO, = 8-18, where is the number of carbon atoms in the alkyl substituent) and neutral phospholipid dioleoylphosphatidylethanolamine (DOPE) were prepared at two molar ratios (CNO/DOPE = 0.4:1 and 1:1) and tested for their transfection activity. Several techniques (SAXS/WAXS, UV-vis, zeta potential measurements, confocal microscopy) were applied to characterize the system in an effort to unravel the relationship among the transfection efficiency, structure, and composition of the lipoplexes.

Self-Assembly Properties of Cationic Gemini Surfactants with Biodegradable Groups in the Spacer.

Self-assembly properties of cationic gemini surfactants with biodegradable amide or ester groups in the spacer were investigated utilising time-resolved fluorescence quenching, dynamic light scattering and zeta potential measurements. A correlation between aggregation parameters such as micelle aggregation number, micelle size and zeta potential with the structure of gemini molecules was made. For gemini molecules with medium spacer lengths, micelle aggregation number does not change much with the surfactant concentration.

Improvement of Glibenclamide Water Solubility by Nanoparticle Preparation.

Glibenclamide, a drug used for the treatment of type 2 diabetes, belongs to Class II of Biopharmaceutical Classification System. It is a highly permeable, but poorly water-soluble drug. Nanoparticles of glibenclamide were prepared by an emulsion solvent evaporation method using dichloromethane as a solvent of glibenclamide and 3% (w/w) aqueous solution of carboxymethyl dextran sodium salt as a stabilizer, which was found as optimal.

DNA-DOPE-gemini surfactants complexes at low surface charge density: from structure to transfection efficiency.

DNA condensation, structure and transfection efficiency of complexes formed by gemini surfactants alkane-α,ω-diyl-bis(dodecyldimethylammonium bromide)s (CnGS12, n = 3, 6 and 12 is the number of alkane spacer carbons), dioleoylphosphatidylethanolamine (CnGS12/DOPE = 0.3 mol/mol) and DNA at low surface charge density were investigated through different techniques. Small angle X-ray diffraction showed a condensed lamellar phase with marked dependence of DNA-DNA distance on (+/-) charge ratio.

Silver Nanoparticles Stabilised by Cationic Gemini Surfactants with Variable Spacer Length.

The present study is focused on the synthesis and investigation of the physicochemical and biological properties of silver nanoparticles stabilized with a series of cationic gemini surfactants having a polymethylene spacer of variable length. UV-VIS spectroscopy, dynamic light scattering, scanning electron microscopy and zeta potential measurements were applied to provide physicochemical characterization of the silver nanoparticles. The mean size values of the nanoparticles were found to be in the 50 to 115 nm range.

Influence of quercetin on the interaction of gliclazide with human serum albumin - spectroscopic and docking approaches.

Protein-binding interactions are displacement reactions which have been implicated as the causative mechanisms in many drug-drug interactions. Thus, the aim of presented study was to analyse human serum albumin-binding displacement interaction between two ligands, hypoglycaemic drug gliclazide and widely distributed plant flavonoid quercetin. Fluorescence analysis was used in order to investigate the effect of substances on intrinsic fluorescence of human serum albumin (HSA) and to define binding and quenching properties of ligand-albumin complexes in binary and ternary systems, respectively.

Synthesis, structural characterization and biological activity of novel Knoevenagel condensates on DLD-1 human colon carcinoma.

Biologically active Knoevenagel condensates (1-14) of diarylheptanoids: 1,7-bis(3-methoxy-4-hydroxyphenyl)hepta-1,7-diene-3,5-dione and 1,7-bis(3-ethoxy-4-hydroxyphenyl)hepta-1,7-diene-3,5-dione, were synthesized and structurally characterized. Compounds 1-14 exhibited cytotoxicity against colon carcinoma cells, and their antiproliferative effect was associated with a significant decrease of multidrug resistance proteins. One of the underlying mechanisms of these effects is the reduction of intracellular and extracellular SOD enzymes by compounds 1, 12 and 14, which render the tumor cells more vulnerable to oxidative stress.

Novel Palladium(II) Complexes that Influence Prominin-1/CD133 Expression and Stem Cell Factor Release in Tumor Cells.

New Pd(II) complexes of 1,7-bis(2-methoxyphenyl)hepta-1,6-diene-3,5-dione were synthesized and structurally characterized. The complexes were tested in vitro on human colon and hepatic carcinoma cell lines, normal hepatic cells and hematopoietic progenitor cells. Biological tests proved that Pd(II) complexes and (containing a curcumin derivative) exhibit a strong in vitro antitumor effect against the cells derived from human colorectal carcinoma and the hepatic metastasis of a colorectal carcinoma.

Antimicrobial Activity and Urease Inhibition of Schiff Bases Derived from Isoniazid and Fluorinated Benzaldehydes and of Their Copper(II) Complexes.

In order to evaluate the influence of substitution on biological properties of Schiff bases and their metal complexes, a series of differently substituted fluorine-containing Schiff bases starting from the drug isoniazid (isonicotinylhydrazide) were prepared and their structures were established by single-crystal X-ray diffraction. Also, four copper(II) complexes of these Schiff bases were synthesized. The prepared compounds were evaluated for their antimicrobial activity and urease inhibition.

Experimental and in silico investigations of organic phosphates and phosphonates sorption on polymer-ceramic monolithic materials and hydroxyapatite.

A method based on experimental and in silico evaluations for investigating interactions of organic phosphates and phosphonates with hydroxyapatite was developed. This quick and easy method is used for determination of differences among organophosphorus compounds of various structures in their mineral binding affinities. Empirical sorption evaluation was carried out using liquid chromatography with tandem mass spectrometry or UV-VIS spectroscopy.

Preparation of Hydrochlorothiazide Nanoparticles for Solubility Enhancement.

Nanoparticles can be considered as a useful tool for improving properties of poorly soluble active ingredients. Hydrochlorothiazide (Class IV of the Biopharmaceutical Classification System) was chosen as a model compound. Antisolvent precipitation-solvent evaporation and emulsion solvent evaporation methods were used for preparation of 18 samples containing hydrochlorothiazide nanoparticles.

DART - LTQ ORBITRAP as an expedient tool for the identification of synthetic cannabinoids.

Synthetic cannabinoids as designer drugs constitute a major problem due to their rapid increase in number and the difficulties connected with their identification in complex mixtures. DART (Direct Analysis in Real Time) has emerged as an advantageous tool for the direct and rapid analysis of complex samples by mass spectrometry. Here we report on the identification of six synthetic cannabinoids originating from seized material in various matrices, employing the combination of ambient pressure ion source DART and hybrid ion trap - LTQ ORBITRAP mass spectrometer.

Partial volumes of cholesterol and monounsaturated diacylphosphatidylcholines in mixed bilayers.

Dispersions of multilamellar liposomes prepared from monounsaturated diacylphosphatidylcholines having 18-24 carbons and from varying amounts of cholesterol were studied by densitometry. Ideal mixing of the studied phosphatidylcholines with cholesterol in the fluid phase was observed. The temperature dependence of partial volumes of both phosphatidylcholines and cholesterol was determined.

Cholesterol protects phosphatidylcholine liposomes from N,N-dimethyl-1-dodekanamine N-oxide influence.

The interaction of N,N-dimethyl-1-dodekanamine N-oxide (C12(CH3)2NO) with egg yolk phosphatidylcholine (EYPC) liposomes containing cholesterol (CHOL) was studied. The perturbation of CHOL-EYPC bilayers in unilamellar liposomes (ULL) was observed by the leakage of fluorescent probe calcein. Weak leakage is observed at low surfactant concentration cC12NO (minimal perturbation of the bilayer) followed by an intensive leakage at a middle cC12NO (creation of pores).

Synthesis of structural analogues of hexadecylphosphocholine and their antineoplastic, antimicrobial and amoebicidal activity.

Twelve derivatives of hexadecylphosphocholine (miltefosine) were synthesized to determine how the position and length of the alkyl chain within the molecule influence their biological activities. The prepared alkylphosphocholines have the same molecular formula as miltefosine. Activity of the compounds was studied against a spectrum of tumour cells, two species of protozoans, bacteria and yeast.

Stimuli responsive polymorphism of C12NO/DOPE/DNA complexes: Effect of pH, temperature and composition.

N,N-dimethyldodecylamine-N-oxide (C12NO) is a surfactant that may exist either in a neutral or cationic protonated form depending on the pH of aqueous solutions. Using small angle X-ray diffraction (SAXD) we observe the rich structural polymorphism of pH responsive complexes prepared due to DNA interaction with C12NO/dioleoylphosphatidylethanolamine (DOPE) vesicles and discuss it in view of utilizing the surfactant for the gene delivery vector of a pH sensitive system. In neutral solutions, the DNA uptake is low, and a lamellar Lα phase formed by C12NO/DOPE is prevailing in the complexes at 0.

Preparation of risedronate nanoparticles by solvent evaporation technique.

One approach for the enhancement of oral drug bioavailability is the technique of nanoparticle preparation. Risedronate sodium (Biopharmaceutical Classification System Class III) was chosen as a model compound with high water solubility and low intestinal permeability. Eighteen samples of risedronate sodium were prepared by the solvent evaporation technique with sodium dodecyl sulfate, polysorbate, macrogol, sodium carboxymethyl cellulose and sodium carboxymethyl dextran as nanoparticle stabilizers applied in three concentrations.

Synthesis, surface and antimicrobial properties of some quaternary ammonium homochiral camphor sulfonamides.

A group of homochiral quaternary ammonium sulfonamides bearing hydrophobic camphor derived moieties were synthesized and characterized. The described synthetic procedure is quick and efficient. The novel quaternary ammonium bromides were tested as antimicrobial and antifungal agents.

Effects of N,N-dimethyl-N-alkylamine-N-oxides on DOPC bilayers in unilamellar vesicles: small-angle neutron scattering study.

Small-angle neutron scattering data were collected from aqueous dispersions of unilamellar vesicles (ULVs) consisting of mixtures of 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine and a homologous series of N,N-dimethyl-N-alkylamine-N-oxides (CnNO, n = 12, 14, 16, and 18, where n is the number of carbon atoms in the alkyl chain). A modeling approach was applied to the neutron scattering curves to obtain the bilayer structural parameters. Particularly, the external (2)H2O/H2O contrast variation technique was carried out on pure dioleoylphosphatidylcholine (DOPC) ULVs to determine the hydrophilic region thickness [Formula: see text] = 9.