In this work, the physicochemical properties and biological activity of nanoemulsions prepared from paraffin oil and stabilized by nonionic surfactants as carriers of curcumin and cerium dioxide nanoparticles were studied.An analysis of the results showed that curcumin was incorporated into the oil droplets while cerium dioxide nanoparticles were adsorbed on the surface of oil droplets.The nanoemulsion droplet size did not exceed 100 nm.The absence of toxicity to mouse embryonic fibroblasts in vitro and after a single intraperitoneal injection to mice in vivo makes the nanoemulsions promising drug carriers for advanced biomedical applications.

Samples of a carbon-mineral catalyst based on natural clay and tire crumb for the reaction of oxidative decomposition of nonionic surfactants by hydrogen peroxide in wastewater have been developed and studied. The iron content in the samples varied in the range of 2.3–3.9 wt %. The effect of sample pyrolysis temperature in the range of 350–800°С on characteristics, the number and type of acid sites on the surface, and the ζ (zeta) potential of colloidal systems based on prepared samples was studied. Using model solutions under static and dynamic conditions, the effect of sample pyrolysis temperature on catalytic properties in the reaction of oxidative decomposition of H2O2 and nonionic surfactant (NS) nonoxynols N-9 by hydrogen peroxide was studied. The best result in the oxidation of nonoxynols N-9 with hydrogen peroxide was obtained in the presence of a carbon-mineral catalyst sample calcined at 650°C.

— Nanoemulsions (NEs) and solid lipid nanoparticles (SLNs) are promising drug delivery systems. In this work, paraffin oil NEs and stearic acid SLNs stabilized with Tween 60 and Span 60 have been studied. NEs with an average droplet diameter of ~50 nm and suspensions of SLNs with an average size of ~30 nm are stable to aggregation for more than 90 days. The rates of penetration of lipid particles into cancer cells (C6 and MCF-7) depend on their sizes. After incubation for 1 h, lipid nanoparticles ~50 nm in size penetrate into cells, are distributed in their internal space, and concentrate in the nuclei. The cytotoxicity of doxorubicin- or thymoquinone-loaded NEs and SLNs against MCF-7 and HTC 116 cell lines is higher than the cytotoxicity of the individual substances. Wherein, unloaded NEs and SLNs show low cytotoxicity. The obtained results demonstrate that paraffin oil NEs and stearic acid SLNs are promising to be used as carriers of both lipophilic and amphiphilic drugs, including doxorubicin and thymoquinone. The accumulation of lipid nanoparticles with sizes smaller than 100 nm in cell nuclei is an advantage of such systems for the delivery of anticancer drugs, because this leads to DNA replication suppression followed by cell apoptosis.

In this work, a noncovalent strategy was successfully used to modify colloidal stability andin vitroandin vivoefficacy of two amphiphilic formulations of the anti-inflammatory drug indomethacin. Namely, nanoemulsions and microemulsions based on oleic acid and nonionic surfactants have been produced and compared. The influence of cationic surfactants cetyltrimethylammonium bromide and its carbamate bearing analogue on the size characteristics, stability and ability to provide prolonged action of loaded drug indomethacin has been evaluated. Adding the positively charged molecules in the surface layer of nanoemulsions and microemulsions has shown the stability increase along with maintaining the size characteristics and homogeneity in time. Moreover, the carbamate modified analogue demonstrated beneficial behavior. Indomethacin loaded in microemulsions and nanoemulsions showed prolonged-release (10%-15% release for 5 h) compared to a free drug (complete release for 5 h). The rate of release of indomethacin from nanoemulsions was slightly higher than from microemulsions and insignificantly decreased with an increase in the concentration of the cationic surfactant. For carbamate surfactant nanocarrier loaded with fluorescence probe Nile Red, the ability to penetrate into the cell was supported by flow cytometry study and visualized by fluorescence microscopy.In vitrotests on anti-inflammatory activity of the systems demonstrated that the blood cell membrane stabilization increased in the case of modified microemulsion. The anti-inflammatory activity of the encapsulated drug was tested in rats using a carrageenan-induced edema model. Nanoemulsions without cationic surfactants appeared more efficient compared to microemulsions. Indomethacin emulsion formulations with carbamate surfactant added showed slower carrageenan-induced edema progression compared to unmodified compositions. Meanwhile, the edema completely disappeared upon treatment with emulsion loaded indomethacin after 4 h in the case of microemulsions versus 5 h in the case of nanoemulsions.

Nanoemulsions are promising disperse systems that can be used as carriers of hydrophobic drugs and biologically active compounds. In this work, nanoemulsions, which contain oleic acid as a dispersed phase and are stabilized with mixtures of nonionic surfactants, Tween 80/Span 80 and Tween 60/Span 60, have been studied. Nanoemulsions stabilized with Tween 80 and Span 80 are unstable. Dispersed phase droplets of such systems undergo intense flocculation and coalescence. Nanoemulsions stabilized with Tween 60 and Span 60 have appeared to be much more stable. The average particle diameter of the dispersed phase remains almost unchanged for a long time at 25°C, as well as in two cycles of heating to 60°C and subsequent cooling to 5°C. Microcalorimetry has been employed to determine the temperatures of phase transitions in such nanoemulsions. The obtained thermograms have two peaks due to melting of oleic acid and a mixed adsorption layer consisting of Tween 60 and Span 60 molecules. Since a solid shell is formed on the surface of oleic acid droplets, such systems can be considered to be nanocapsules.

This work presents the results of a study on the effect of ionic surfactant cetriltrimethylammonium chloride (CTAB) on the size and ζ-potential of lipid nanoemulsions composed of oleic acid, prepared by temperature phase inversion method and stabilized by nonionic surfactants — Tween 60, Span 60

Organo-mineral derivatives of montmorillonite modified by salts of quaternary ammonium compounds are promising adsorbents for wastewater purification from heavy metal anions, as well as anionic dyes and pesticides. The understanding of the mechanism of anion adsorption by the example of montmorillonite modified by didecyldimethylammonium chloride cationic surfactant is expanded. The high rate of chromium anion adsorption, the appearance of adsorption capacity only during charge exchange of the surface, and the pH dependence of adsorption, including for pH-independent nitrate anions, indicate that a significant contribution to adsorption of anions is made by silanol and aluminol groups on the edge surface of the aluminosilicate layers of the mineral. The redistribution of access to various types of adsorption centers of the surface for adsorptive is the mechanism of inversion of the adsorption properties for montmorillonite. The inner negatively charged surface is screened by the double layer of the surfactant molecules that block the interlayer space. The surfactant molecules are not hydrated, which impedes delamination of the mineral in aqueous medium.