Cetrimonium Surfactants with Biologically Active Counter Ions as Self-Immolative Drug Delivery Systems

Novel derivatives of cationic surfactant cetyltrimethylammonium bromide (CTAB) possessing anions of ibuprofen and naproxen as hydrophobic counterions were synthesized and characterized using Fourier transform infrared and differential electronic absorption spectroscopy. The self-assembly of each surfactant was investigated using surface tensiometry. The self-immolative nature of these compounds was analyzed through study of their behavior in response to trigger such as medium pH. ADMET-SAR (adsorption, distribution, metabolism, excretion, toxicity – structure-activity relationship) profiles of synthesized surfactants were generated using admetSAR v. 1.0). The cetrimonium drugs exhibited better profiles than the corresponding pure drugs, save the aqueous solubility which was reduced due to hydrophobicity of counterions.

Fabrication of In(III)-alizarin red S complex trap for efficient detection of fluoride ion in aqueous environs

The work discusses about the synthesis of indium-alizarin red S complex followed by its application toward the sensing of F¯ ion. At first, the interaction between indium and alizarin red S dye was studied at three different pH medium, pH 4, 7 and 9, of which pH 7 gave the best result. The indium-alizarin red S complex so obtained was then utilized for the ratiometric sensing of fluoride ion using absorption spectroscopy with variation of temperature. The lowest limit of detection (0.040 mM) was obtained at 313 K. The mechanism for the sensing of F¯ ion was then investigated using isothermal titration calorimetry. The endothermic nature of the interaction between F¯ ion with indium-alizarin red S complex shows temperature dependence on the sensing experiment. At the end, the utility of the technique toward natural sample was also examined. The present work reports a simple, rapid and efficient detection of fluoride anion in environmental water samples.

Adjusting the Structure of β-Cyclodextrin to Improve Complexation of Anthraquinone-Derived Drugs

β-Cyclodextrin (CD) derivatives containing an aromatic triazole ring were studied as potential carriers of the following drugs containing an anthraquinone moiety: anthraquinone-2-sulfonic acid (AQ2S); anthraquinone-2-carboxylic acid (AQ2CA); and a common anthracycline, daunorubicin (DNR). UV-Vis and voltammetry measurements were carried out to determine the solubilities and association constants of the complexes formed, and the results revealed the unique properties of the chosen CDs as effective pH-dependent drug complexing agents. The association constants of the drug complexes with the CDs containing a triazole and lipoic acid (βCDLip) or galactosamine (βCDGAL), were significantly larger than that of the native βCD. The AQ2CA and AQ2S drugs were poorly soluble, and their solubilities increased as a result of complex formation with βCDLip and βCDGAL ligands. AQ2CA and AQ2S are negatively charged at pH 7.4. Therefore, they were less prone to form an inclusion complex with the hydrophobic CD cavity than at pH 3 (characteristic of gastric juices) when protonated. The βCDTriazole and βCDGAL ligands were found to form weaker inclusion complexes with the positively charged drug DNR at an acidic pH (pH 5.5) than in a neutral medium (pH 7.4) in which the drug dissociates to its neutral, uncharged form. This pH dependence is favorable for antitumor applications.

Iron Supplement-Enhanced Growth and Development of Hydrangea macrophylla In Vitro under Normal and High pH

Hydrangea macrophylla is a popular perennial ornamental shrub commercially grown as potted plants, landscape plants, and cut flowers. In the process of reproduction and production of ornamental plants, the absorption of nutrients directly determines the value of the ornamental plants. Hydrangea macrophylla is very sensitive to the content and absorption of the micronutrient iron (Fe) that affects growth of its shoots. However, the physiological activity of Fe as affected by deficiency or supplementation is unknown. This work aimed at preliminary exploring the relationship between Fe and photosynthesis, and also to find the most favorable iron source and level of pH for the growth of H. macrophylla. Two Fe sources, non-chelated iron sulfate (FeSO4) and iron ethylenediaminetetraacetic acid (Fe-EDTA), were supplemented to the multipurpose medium with a final Fe concentration of 2.78 mg·L−1. The medium without any Fe supplementation was used as the control. The pH of the agar-solidified medium was adjusted to either 4.70, 5.70, or 6.70, before autoclaving. The experiment was conducted in a culture room for 60 days with 25/18 °C day and night temperatures, and a 16-hour photoperiod provided at a light intensity of 50 mmol·m−2·s−1 photosynthetic photon flux density (PPFD) from white light-emitting diodes. Supplementary Fe increased the tissue Fe content, and leaves were greener with the medium pH of 4.70, regardless of the Fe source. Compared to the control, the number of leaves for plantlets treated with FeSO4 and Fe-EDTA were 2.0 and 1.5 times greater, respectively. The chlorophyll, macronutrient, and micronutrient contents were the greatest with Fe-EDTA at pH 4.70. Furthermore, the Fe in the leaf affected the photosynthesis by regulating stomata development, pigment content, and antioxidant system, and also by adjusting the expression of genes related to Fe absorption, transport, and redistribution. Supplementation of Fe in a form chelated with EDTA along with a medium pH of 4.70 was found to be the best for the growth and development of H. macrophylla plantlets cultured in vitro.

Combination effect of diurnal exposure to sucrose and nocturnal exposure to lactose on enamel demineralization

We have hypothesized that the association between human milk and caries in breastfeeding children could be explained by the combination of a diurnal cariogenic diet with the nocturnal lactose fermentation, conditions simulated in this experimental study. Cariogenic biofilm was formed on bovine enamel slabs, which were exposed 8x/day for 3 min to a 10% sucrose solution, simulating a highly cariogenic diurnal diet, or 50 mM NaCl solution (control). Simulating the nocturnal retention of milk in mouth, biofilms were transferred to culture medium containing 0.7% lactose for 2 h, or only to culture medium (control). Four groups were designed (n=12): Ctrl, no exposure to diurnal sucrose or nocturnal lactose; Lac, only nocturnal exposure to lactose (2 h); Suc, only diurnal exposure to sucrose (8x/day); and Suc→Lac, diurnal exposure to sucrose (8x/day) followed by nocturnal exposure to lactose (2 h). The medium was changed 3x/day, at the beginning of the day, and after diurnal and nocturnal exposures. Calcium in the medium was determined as chemical indicator of partial demineralizations occurred during the diurnal and the nocturnal treatments; the medium pH was also determined. After 96 h of growth, biofilms were harvested to evaluate CFU, biomass, and extracellular polysaccharides, soluble and insoluble. The percentage of enamel surface hardness loss (%SHL) was evaluated as cumulative demineralization. Data were analyzed by one-way ANOVA, Tukey’s test (α=5%). Highest %SHL (p<0.05) was found for Suc→Lac (40.6%) group when compared to Suc (32.1%), Lac (7.7%), and Ctrl (3.8%). Calcium released during the diurnal and nocturnal treatments were respectively: Suc→Lac=Suc>Lac=Ctrl and Suc→Lac=Lac>Suc=Ctrl (p<0.05). Regarding Ctr group, calcium released from nocturnal lactose fermentation by Suc→Lac group was 4-fold greater than that provoked by Lac group. The findings were supported by the pH of the media. The data suggest that the biofilm formed under diurnal exposure to sucrose enhances the cariogenicity of nocturnal exposure to lactose.

Design of High-Relaxivity Polyelectrolyte Nanocapsules Based on Citrate Complexes of Gadolinium(III) of Unusual Composition

Through nuclear magnetic relaxation and pH-metry, the details of the complexation of gadolinium(III) ions with citric acid (H4L) in water and aqueous solutions of cationic polyelectrolytes are established. It is shown that the presence of poly(ethylene imine) (PEI) in solution affects magnetic relaxation behavior of gadolinium(III) complexes with citric acid (Cit) to a greater extent than polydiallyldimethylammonium chloride (PDDC). A large increase in relaxivity (up to 50 mM−1s−1) in the broad pH range (4–8) is revealed for the gadolinium(III)–citric acid–PEI system, which is particularly strong in the case of PEI with the molecular weight of 25 and 60 kDa. In weakly acidic medium (pH 3–7), the presence of PEI results in the formation of two tris-ligand associates [Gd(H2L)3]3− and [Gd(H2L)2(HL)]4−, which do not exist in aqueous medium. In weakly alkaline medium (pH 7–10), formation of ternary complexes Gd(III)–Cit–PEI with the Gd(III)–to–Cit ratio of 1:2 is evidenced. Using transmission electron microscopy (TEM) and dynamic light scattering techniques (DLS), the formation of the particles with the size of 50–100 nm possessing narrow molecular-mass distribution (PDI 0.08) is determined in the solution containing associate of PEI with tris-ligand complex [Gd(H2L)2(HL)]4−.

Biotechnology: identification and evaluation of the Bacillus cereus amylolytic activity

Biotechnology is the branch of science that uses molecules, viruses, microorganisms, cells, animals, plants or part of them in technological processes to generate benefits for humans, to flora, fauna and the environment. In this context, enzymes are natural biocatalysts that present substrate specificity and extreme importance to vital processes, as they develop indispensable functions in biochemical reactions of cell metabolism, and can be used in biotechnological processes. Knowing the human needs, for a world population of about 7.7 billion people and the functional usefulness of enzymes, there is, on the one hand, a gigantic demand for the consumption of various products in the agricultural sector, processed and industrialized, such as: food, beverages, clothing in the textile sector, medicines, vaccines, cosmetics in the chemical-pharmaceutical sector, as well as in the production of paper and fuels, in which enzymes, mainly amylases, have been widely used in production processes. In this work, experiments were carried out with the wild Bacillus cereus bacterium to verify the production of amylases, the results obtained could demonstrate the formation of amylolysis halos around the colonies in Petri dishes containing Tryptic Soy Agar + starch (1%) medium, pH 7.3 and grown in a biological oven at 37oC for 24 hours, when revealed in iodine vapor; the Amylolysis Index (AI) was 3.3 and the efficiency of starch substrate degradation by amylases was greater than 90% in the evaluated treatments.

Adjusting the Structure of β-cyclodextrin to Improve Complexation of Anthraquinone-derived Drugs

&beta;-cyclodextrin (CD) derivatives containing aromatic triazole ring were studied as potential carriers of drugs containing an anthraquinone moiety in the structure: anthraquinone-2-sulfonic acid (AQ2S), anthraquinone-2-carboxylic acid (AQ2CA) and a common anthracycline, daunorubicin (DNR). UV-Vis and voltammetry measurements were carried out to determine the solubilities and stability constants of the complexes formed and revealed the unique properties of the chosen CDs as effective pH dependent drug complexing agents. The stability constants of the drug complexes with the CDs containing triazole: &beta;CDLip and &beta;CDGAL were significantly larger than with the native &beta;CD. The AQ2CA and AQ2S drugs are ill-soluble and their solubilities increased as the result of complex formation with &beta;CDLip and &beta;CDGAL ligands. AQ2CA, AQ2S were negatively charged at pH 7.4 and therefore they were less prone to form inclusion complex with the hydrophobic CD cavity than at pH 3 (characteristic of gastric juices) when they were protonated. &beta;CDTriazole and &beta;CDGAL ligands were found to form weaker inclusion complexes with the positively charged drug DNR at acidic pH (pH 5.5) than in the neutral medium (pH 7.4) when the drug dissociates to the neutral, uncharged form. This pH dependence is favorable for anti-tumor applications.

CORN OIL REMOVAL BY ADVANCED OXIDATION PROCESSES IN COMPARTION WITH CASTOR AND COCONUT OILS

The AOPs advanced oxidation process has been studied in three ways: (UV/H₂O₂), Fenton, and Photo-Fenton in artificial water treating from vegetable oils. The corn, castor, and coconut oils emulsion were prepared and treated by AOPs. Several variables were studied: time, pH, mixing speed, temperature, the dose of chemicals (H₂O₂ & Fe2SO4.7H2O), and finally the oil concentration. The best conditions were obtained in several experiments where the Fenton and Photo-Fenton process operates in an acidic medium (pH = 3.5), while the UV/H₂O₂ process operates with the neutral medium (pH = 7). The optimum temperature for the Photo-Fenton and UV/H₂O₂ processes is 40°C, and for the Fenton process is 20°C. While there was an effect of mixing speed, higher efficiency was achieved at (1000 rpm) for the Photo-Fenton process and (500 rpm) for the Fenton and UV/H₂O₂ processes. Also, the H₂O₂ concentration was at (500 mg/L) for all processes, when the Fe2SO4.7H2O concentration for the photo-Fenton process = (50 mg/L), and for the Fenton process = (250 mg/L). Oil concentration = (1750 mg/L). Optimum conditions were applied to treat vegetable oils, the Fenton process gave a maximum removal efficiency of 95.2% for corn oil (COD 12800 to 610 mg/L), 94.5% for castor oil, while 57.5% for coconut oil after the total reaction time (180 minutes). The Photo-Fenton process gave removal efficiencies: 93% for corn oil (COD 12500 to 870 mg/L), 83.8% for castor oil, and 61.6% for coconut oil. The UV/H₂O₂ process gave removal efficiencies: 69.8% for corn oil, 32% for castor oil, and 23.4% for coconut oil after the total irradiation time. As real wastewater, the treatment was acceptable and achieved an efficiency of 44.7%, 89.2%, and 83.8% for the UV/H₂O₂, Fenton, and Photo-Fenton processes, respectively.