Desulfurisation of oils using ionic liquids: selection of cationic and anionic components to enhance extraction efficiency

Extraction of dibenzothiophene from dodecane using ionic liquids as the extracting phase has been investigated for a range of ionic liquids with varying cation classes (imidazolium, pyridinium, and pyrrolidinium) and a range of anion types using liquid-liquid partition studies and QSPR (quantitative structure-activity relationship) analysis. The partition ratio of dibenzothiophene to the ionic liquids showed a clear variation with cation class (dimethylpyridinium > methylpyridinium > pyridinium approximate to imidazolium approximate to pyrrolidinium), with much less significant variation with anion type. Polyaromatic quinolinium-based ionic liquids showed even greater extraction potential, but were compromised by higher melting points. For example, 1-butyl-6-methylquinolinium bis{(trifluoromethyl)sulfonyl} amide (mp 47 degrees C) extracted 90% of the available dibenzothiophene from dodecane at 60 degrees C.

The contents of proteins and phospholipids in cloudy (veiled) virgin olive oils

Extra virgin olive oil is produced in the form of a

Elimination kinetic of 17 beta-estradiol 3-benzoate and 17 beta-nandrolone laureate ester metabolites in calves' urine

Efficient control of the illegal use of anabolic steroids must both take into account metabolic patterns and associated kinetics of elimination; in this context, an extensive animal experiment involving 24 calves and consisting of three administrations of 17 beta-estradiol 3-benzoate and 17 beta-nandrolone laureate esters was carried out over 50 days. Urine samples were regularly collected during the experiment from all treated and non-treated calves. For sample preparation, a single step high throughput protocol based on 96-well C-18 SPE was developed and validated according to the European Decision 2002/657/EC requirements. Decision limits (CC alpha) for steroids were below 0.1 mu g L-1, except for 19-norandrosterone (CC alpha = 0.7 mu g L-1) and estrone (CC alpha = 0.3 mu g L-1). Kinetics of elimination of the administered 17 beta-estradiol 3-benzoate and 17 beta-nandrolone laureate were established by monitoring 17 beta-estradiol, 17 alpha-estradiol, estrone and 17 beta-nandrolone, 17 alpha-nandrolone, 19-noretiocholanolone, 19-norandrostenedione, respectively. All animals demonstrated homogeneous patterns of elimination both from a qualitative (metabolite profile) and quantitative point of view (elimination kinetics in urine). Most abundant metabolites were 17 alpha-estradiol and 17 alpha-nandrolone (> 20 and 2 mg L-1, respectively after 17 beta-estradiol 3-benzoate and 17 beta-nandrolone laureate administration) whereas 17 beta-estradiol, estrone, 17 beta-nandrolone, 19-noretiocholanolone and 19-norandrostenedione were found as secondary metabolites at concentration values up to the mu g L-1 level. No significant difference was observed between male and female animals. The effect of several consecutive injections on elimination profiles was studied and revealed a tendency toward a decrease in the biotransformation of administered steroid 17 beta form. (c) 2008 Elsevier Ltd. All rights reserved.

Glycosylation of low-density lipoprotein enhances cholesteryl ester synthesis in human monocyte-derived macrophages

Glucose can react with the lysine residues of low-density lipoproteins (LDLs) and convert the lipoprotein to a form with a receptor-mediated uptake by cultured cells that is impaired. However, in contrast to other modified lipoproteins taken up by both murine and human macrophages via the scavenger-receptor pathway that may induce the formation of foam cells, glycosylated LDL is not recognized by murine macrophages, and thus far, it has not been shown to lead to marked intracellular accumulation of cholesterol in human macrophages. This study illustrates that glycosylated LDL incubated with human monocyte-derived macrophages, at a concentration of 100 micrograms LDL/ml medium, stimulates significantly more cholesteryl ester (CE) synthesis than does control LDL (10.65 +/- 1.5 vs. 4.8 +/- 0.13 nmol.mg-1 cell protein.20 h-1; P less than .05). At LDL concentrations similar to those of plasma, the rate of CE synthesis in macrophages incubated with glycosylated LDL is more markedly enhanced than that observed in cells incubated with control LDL (3-fold increase). The marked stimulation of CE synthesis in human macrophages exposed to glycosylated LDL is paralleled by a significant increase in CE accumulation in these cells (P less than .001). The increase in CE synthesis and accumulation seem to be mediated by an increase in the degradation of glycosylated LDL by human macrophages. Glycosylated LDL enters the macrophages and is degraded by the classic LDL-receptor pathway in slightly smaller amounts than control LDL, but its degradation by pathways other than the classic LDL receptor or scavenger receptor is markedly enhanced.(ABSTRACT TRUNCATED AT 250 WORDS)

Stimulation of cholesteryl ester synthesis in human monocyte-derived macrophages by low-density lipoproteins from type 1 (insulin-dependent) diabetic patients:the influence of non-enzymatic glycosylation of low-density lipoproteins

Diabetes mellitus is an independent risk factor in the development of atherosclerosis. In this study we aimed to demonstrate whether there is an abnormal interaction between low-density lipoproteins from diabetic patients and human macrophages. We measured cholesteryl ester synthesis and cholesteryl ester accumulation in human monocyte-derived macrophages (obtained from non-diabetic donors) incubated with low density lipoproteins from Type 1 (insulin-dependent) diabetic patients in good or fair glycaemic control. Low density lipoproteins from the diabetic patients stimulated more cholesteryl ester synthesis than low density lipoproteins from non-diabetic control subjects (7.19 +/- 1.19 vs 6.11 +/- 0.94 nmol/mg cell protein/20 h, mean +/- SEM, p less than 0.05). The stimulation of cholesteryl ester synthesis by low density lipoproteins isolated from diabetic patients was paralleled by a significant increase in intracellular cholesteryl ester accumulation (p less than 0.02). There were no significant differences in the lipid composition of low density lipoproteins between the diabetic and control groups. Non-enzymatic glycosylation of low density lipoproteins was higher in the diabetic group (p less than 0.01) and correlated significantly with cholesteryl ester synthesis (r = 0.58). Similarly, low-density lipoproteins obtained from non-diabetic subjects and glycosylated in vitro stimulated more cholesteryl ester synthesis in macrophages than control low density lipoproteins. The increase in cholesteryl ester synthesis and accumulation by cells exposed to low density lipoproteins from diabetic patients seems to be mediated by an increased uptake of these lipoproteins by macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)

Design of an intravaginal ring for the controlled delivery of 17b-estradiol as its 3-acetate ester

Suitable ester prodrugs of 17b-estradiol are identified, thus permitting effective sustained and controlled estrogen replacement therapy (ERT) from an elastomeric, silicone intravaginal ring (IVR). IVR devices of reservoir design were prepared by blending silicone elastomer base with n-propylorthosilicate (cross-linker) and 10% w/w of 17b-estradiol or an ester prodrug, the mix being activated with 0.5% w/w stannous octoate and cured at 808C for 2 min. A rate-controlling membrane was similarly prepared, without the active agent. IVR devices were of cross-sectional diameter 9 mm, outer diameter 54 mm, with core cross-sectional diameter of 2 mm and core length varied as required. Sink conditions were evident for the 17b-estradiol esters in 1.0% aqueous benzalkonium chloride solution. The low release rates into 0.9% w/v saline of the lipophilic valerate and benzoate esters were due to their intrinsically low aqueous solubilities. In vivo, these esters failed to raise plasma estradiol above baseline levels in postmenopausal human volunteers, despite good in vitro release characteristics under sink conditions. The best release rates under sink conditions, in combination with substantial aqueous solubilities as indicated by the release rates into saline, were observed for the acetate and propionate esters. A
combination of drug release characteristics, short plasma half-life and a toxicologically acceptable hydrolysis product indicated that 17b-estradiol-3-acetate was the prodrug of choice for IVR delivery of ERT. In vivo, an IVR device releasing
100 mg/day of estradiol as its 3-acetate ester maintained over 84 days a circulating plasma concentration in the region of 300 pmol l , within the clinically desirable range for ERT.

Evaluation of methodologies to determine vegetable oil species present in oil mixtures: Proposition of an approach to meet the EU legislation demands for correct vegetable oils labelling

Refined vegetable oils are widely used in the food industry as ingredients or components in many processed food products in the form of oil blends. To date, the generic term 'vegetable oil' has been used in the labelling of food containing oil blends. With the introduction of new EU Regulation for Food Information (1169/2011) due to take effect in 2014, the oil species used must be clearly identified on the package and there is a need for development of fit for purpose methodology for industry and regulators alike to verify the oil species present in a product. The available methodologies that may be employed to authenticate the botanical origin of a vegetable oil admixture were reviewed and evaluated. The majority of the sources however, described techniques applied to crude vegetable oils such as olive oil due to the lack of refined vegetable oil focused studies. Nevertheless, DNA based typing methods and stable isotopes procedures were found not suitable for this particular purpose due to several issues. Only a small number of specific chromatographic and spectroscopic fingerprinting methods in either targeted or untargeted mode were found to be applicable in potentially providing a solution to this complex authenticity problem. Applied as a single method in isolation, these techniques would be able to give limited information on the oils identity as signals obtained for various oil types may well be overlapping. Therefore, more complex and combined approaches are likely to be needed to identify the oil species present in oil blends employing a stepwise approach in combination with advanced chemometrics. Options to provide such a methodology are outlined in the current study.

Identification of oil mixtures in extracted and refined vegetable oils

Identification of adulteration in mechanically extracted oils or the botanical origin of refined vegetable oil blends can be effectively achieved through the combination of spectroscopic methods and chemometric techniques. Chromatographic methods remain highly relevant but suffer from various limitations which derive from natural compositional variation. Modern multivariate techniques have demonstrated that it is possible to identify patterns and effectively classify unknown samples in both cases. Development of robust analytical methodologies requires however vigorous validation. Spectroscopic methods combined with chemometric techniques lack established validation protocols and this might hinder their use by law enforcement authorities. 

Exploring molecular recognition pathways within a family of gelators with different hydrogen bonding motifs

We report the synthesis of a family of gelators in which alkyl chains are connected to the amino groups of L-lysine methyl ester using a range of different hydrogen bonding linking groups (carbamate, amide, urea, thiourea and diacylhydrazine) using simple synthetic methodology based on isocyanate or acid chloride chemistry. The ability of these compounds to gelate organic solvents such as toluene or cyclohexane can be directly related to the ability of the linking group to form intermolecular hydrogen bonds. In general terms, the ability to structure solvents can be considered as: thiourea <carbamate <amide <urea similar to diacylhydrazine. This process has been confirmed by thermal measurements, scanning electron microscopy (SEM) and infrared and circular dichroism spectroscopies. By deprotecting the methyl ester group, we have demonstrated that a balance between hydrophobic and hydrophilic groups is essential-if the system has too much hydrophilicity (e. g., diacylhydrazine, urea) it will not form gels due to low solubility in the organic media. However, the less effective gelators based on amide and carbamate linkages are enhanced by converting the methyl ester to a carboxylic acid. Furthermore, subsequent mixing of the acid with a second component (diaminododecane) further enhances the ability to form networks, and, in the case of the amide, generates a two-component gel, which can immobilise a wide range of solvents of industrial interest including petrol and diesel (fuel oils), olive oil and sunflower oil (renewable food oils) and ethyl laurate, isopropyl myristate and isopropyl palmitate (oils used in pharmaceutical formulation). The gels are all thermoreversible, and may therefore be useful in controlled release/formulation applications.

Synthesis and release kinetics of polymerisable ester drug conjugates towards pH-responsive infection-resistant urinary biomaterials

Herein we report the synthesis, characterisation and hydrolytic release kinetics of a suite of novel, polymerisable ester quinolone conjugates with varying alkenyl chain lengths. Hydrolysis was shown to proceed up to 17-fold faster upon elevation of pH from neutral to pH 9.29, making these conjugates attractive for the development of 'designer' infection-resistant urinary biomaterials exploiting the increase in urine pH reported at the onset of catheter-associated infection to trigger drug release. (C) 2013 Elsevier Ltd. All rights reserved.