Volume 51, Issue 4

Today, noroviruses (NoV) are the world's most common cause of human gastroenteritis. Because of its low infectious dose and its ability to persist in the environment, the virus can be easily transmitted from person-to-person. In addition, surfaces like toilet seats, door handles or clothes worn by infected patients might serve as transmission vectors. Although environmental contamination plays a big role in the spread of the virus, little is known about how contaminated surfaces and textiles can be cleaned efficiently to prevent infections. To estimate the lifelike situation, textiles were contaminated with NoV-containing stool and washed in a normal household machine using laundry detergents with or without activated oxygen bleach at different temperatures. The obtained results show that a sufficient inactivation of NoV-contaminated fabric requires a washing temperature of at least 60°C, even if a detergent with activated oxygen bleach is used.

The dispersion of bioactive glass, (BG), sample was studied using cetyltrimethylammonium bromide (CTAB). An array of experimental techniques like adsorption, Zeta potential and turbidity were used to achieve this goal. Turbidity was used as a parameter to reflect the degree of dispersion where a higher value of turbidity represents higher dispersion efficiency. Dispersion of the BG particles was largely affected by CTAB concentration and the solution pH. Dispersion of the BG particles was increased with increasing of CTAB concentration till the CMC of CTAB is reached. Above the CMC, the BG particles become hydrophilic causing a decrease in glass dispersion. On the other hand, dispersion of the BG particles was affected with the solution pH. It was increased with increasing pH till pH 9. At higher pH, dispersion was decreased where the formation of micelles is favored.

Water/oil emulsions are formed in oil wells due to the presence of natural surfactants. As water/oil phase separation is necessary before oil refining, demulsifiers are used to break water/oil emulsions. In this work, environmentally friendly ionic surface-active choline carboxylates were synthesized from anionic exchange involving choline chloride under microwave dielectric heating. Microwave irradiation was also employed as a fast method for following the kinetics of the demulsification process with the synthesized demulsifiers. Choline palmitate showed the best performance as demulsifier.

New sulfonamide tetrachloro metallate complexes that might possess strong carbonic anhydrase (CA) inhibitory properties were synthesized by the reaction of 4-amino-N-(quinoxalin-2-yl) benzene sulfonamide (sulfaquinoxaline) hydrochloride with different metal chlorides, i.e. CoCl 2 , CuCl 2 or SnCl 2 . The produced metal complexes of the sulfonamide derivative, containing divalent cations, were characterized by standard procedures. These metal complexes might possess topical antiglaucoma properties which might make them more effective as pharmacological agents. The synthesized complexes exhibited significant cytotoxic activity against colon HCT-116 human cell line. Surface properties of these surfactants were investigated. The surface properties studies included critical micelle concentration (CMC), maximum surface excess (Γ max ), minimum surface area (A min ). Free energy of micellization (ΔG° mic ) and adsorption (ΔG° ads ) were calculated.

In aqueous acidic media, picolinic acid, 2,3-dipicolinic acid, and 2,6-dipicolinic acid promoted Cr(VI) oxidation of lactose to lactobionic acid has been carried out at room temperature. A possible reaction mechanism, which is based on the kinetic results and the product analysis, has been proposed. The anionic surfactant sodium dodecyl sulphate (SDS) and nonionic surfactant Triton-X-100 (TX-100) accelerate the process while the cationic surfactant N -cetylpyridinium chloride (CPC) retards the reaction.

A cloud point extraction (CPE) process using the two nonionic surfactants, Tergitol 15-S-9 and Tergitol 15-S-7, mixtures of secondary ethoxylated alcohols, to extract selected polycyclic aromatic hydrocarbons (PAHs) from aqueous solutions at 25°C was investigated. Cloud point temperatures (CPTs) of selected nonionic surfactants were studied against the effect of added electrolytes on their cloud points. Sodium iodide could increase the cloud points of selected nonionic surfactants, i.e., the salt-in effect, whereas sodium chloride, sodium phosphate and sodium sulfate could decrease the cloud point, i.e., the salt-out effect. Cloud point temperatures (CPTs) of these micellar solutions were regulated and reduced enough with addition of sodium phosphate and sodium sulfate, so that the cloud point extraction (CPE) process could be facilitated at 25°C. It was found that a higher preconcentration factor could be achieved in the micellar solution having a lower surfactant concentration. The average preconcentration factor was also discussed as a function of surfactant concentration used in the CPE process.

An objective of this work is analysis of influence of selected alcohols from the group of enhancers (ethanol, propan-1-ol, propan-2-ol) and humectants (ethane-1,2-diol, propane-1,2-diol and propane-1,2,3-triol) in the hydrogels containing carbethopendecinium bromide on their associative (critical micelle concentration and thermodynamic parameters) and release properties (pH, percentage of drug release and the release rate constant). The studied hydrogels contained constant amounts of the gel-creating basis (polymer chitosan – 2.5% w/w), drug carbethopendecinium bromide (Septonex) – 1.0% w/w and additive of alcohol in 5 and 10% w/w concentrations. Associative parameter – critical micelle concentration (CMC) was evaluated by conductometric measurements. The CMC significantly increased in the environment of alcohols in comparison with water solutions as many as 50 times, while concentration of alcohols ranged within W = 0–100% mass fractions. Micellization in the both environments was spontaneous (ΔG m < 0), and from the energetic point of view it was exothermic (ΔH m < 0). The additive of alcohols in hydrogels supported the drug relase from hydrogels. As the concentration of alcohols increased the mass percentage of the drug released from gel increased as well.

Quaternary ammonium surfactants 3a–d, with diether linkages in the backbone between hydrocarbon chains and the ammonium head groups, were synthesized as potential soft-template agents for the preparation of mesoporous materials. Varying the length of their carbon chains was expected to control the pore sizes of the corresponding mesoporous materials prepared. The critical micelle concentration (CMC) and γ cmc (surface tension of the CMC) of these surfactants were measured by surface tension method.

Sulfosuccinate esters are vastly used in different formulations as wetting agents and dispersants. Hemi-ester, diester, ethoxylated, and ethoxylated ester derivatives of maleic anhydride, maleic acid, and fumaric acid are converted to the saturated or corresponding sulfosuccinates by the reaction of the double bond with sodium bisulfite in basic media. The roles of anionic, cationic and non-ionic surfactants have been investigated. Appropriate surfactants have been applied in the absence of a peroxide initiator. The results obtained show increased reaction rates. Characterization of the products was performed by FTIR and 1 H-NMR spectroscopy. Ethoxylated isooctyl maleate derivative was used as the starting material and the sulfonation agents used were sodium bisulfite and meta bisulfite.