Phytosterols and γ-Oryzanol as Cholesterol Solid Phase Modifiers during Digestion.

Literature reports that ingestion of phytosterols and γ-oryzanol contributes to cholesterol lowering. Despite in vivo observations, thermodynamic phase equilibria could explain phenomena occurring during digestion leading to such effects. To advance the observations made by previous literature, this study was aimed at describing the complete solid-liquid phase equilibrium diagrams of cholesterol + phytosterol and γ-oryzanol systems by DSC, evaluating them by powder X-ray, microscopy, and thermodynamic modeling. Additionally, this study evaluated the phenomena observed by an in vitro digestibility method. Results confirmed the formation of solid solution in the cholesterol + phytosterols system at any concentration and that cholesterol + γ-oryzanol mixtures formed stable liquid crystalline phases with a significant melting temperature depression. The in vitro protocol supported the idea that the same phenomena can occur during digestion in which mechanochemical forces were probably the mechanisms promoting cholesterol solid phase changes in the presence of such phytocompounds. In this case, these changes could alter cholesterol solubility and possibly its absorption in the gastrointestinal lumen.

Rifle bullets comparison by wavelength dispersive X-ray fluorescence spectroscopy and chemometric analysis.

Despite Federal Bureau of Investigation Laboratory announcing the discontinuation of bullet lead examinations, knowledge of the composition of the bullets has been used as an alternative means of identifying their origin, achieving success in some case studies. In this work, wavelength dispersion X-ray fluorescence (WDXRF) and chemometrics were used for the analysis of rifle bullets, in order to identify the spectral similarities of these samples. For this purpose, 54 lead core fragments from 7.62 mm rifle bullets from 5 different manufacturers were obtained: Companhia Brasileira de Cartuchos (CBC), Israel Military Industries (IMI), Federal Cartridge (FC), Fray Luiz Beltrán (FLB) and Zavod Vlasim (ZV). Principal components analysis (PCA) discriminated the five groups of bullets according to their manufacturers in a three-dimensional scores graph, where 3 principal components accounted for>99% of the variability between the samples. The spectral region for Sb and the scattering region together proved to be determinant for discrimination of the groups. The dendrogram presented in the hierarchical cluster analysis (HCA) showed the formation of five groups. The k-nearest neighbor algorithm (k-NN) and soft independent modeling of class analogy (SIMCA) correctly classified all samples of the test set. X-ray scattering spectrum were used for the first time in the analysis of the fragments and contributed to the grouping of samples from the same manufacturers. The results indicate that the WDXRF technique is suitable for forensic purposes in case studies, as, besides being quick and relatively simple, it has the advantage of preserving evidence.

Non-invasive Transdermal Delivery of Human Insulin Using Ionic Liquids: In vitro Studies.

In this research project, synthesis and characterization of ionic liquids and their subsequent utilization as facilitators of transdermal delivery of human insulin was pursued. Choline geranate and choline oleate ionic liquids (and their deep eutectic solvents) were produced and characterized by nuclear magnetic resonance (1H NMR), water content, oxidative stability, cytotoxicity and genotoxicity assays, and ability to promote transdermal protein permeation. The results gathered clearly suggest that all ionic liquids were able to promote/facilitate transdermal permeation of insulin, although to various extents. In particular, choline geranate 1:2 combined with its virtually nil cyto- and geno-toxicity was chosen to be incorporated in a biopolymeric formulation making it a suitable facilitator aiming at transdermal delivery of insulin.

Influence of Pluronic F127 microenvironments on the photochemical nitric oxide release from S-nitrosoglutathione.

Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) (F127) hydrogels have been used to deliver nitric oxide (NO) topically in biomedical applications. Here, the effect of F127 microenvironments on the photochemical NO release from S-nitrosoglutathione (GSNO) was investigated in F127 solutions 7.6 wt% 15 wt% and 22.5 wt% at 15 °C and 37 °C. Small-angle X-ray Scattering (SAXS) and Differential Scanning Calorimetry (DSC) measurements, along with proton Nuclear Magnetic Resonance (1H NMR) spectral shifts and T2 relaxation data at six different concentration-temperature conditions, allowed identifying F127 microphases characterized by: a sol phase of unimers; micelles in non-defined periodic order, and a gel phase of cubic packed micelles. Kinetic measurements showed that GSNO photodecompositon proceeds faster in micellized F127 where GSNO is segregated to the intermicellar microenvironment. Real time kinetic monitoring of NO release and T2 relaxation profiles showed that NO is preferentially partitioned into the hydrophobic PPO cores of the F127 micelles, with the consequent decrease in its rate of release to the gas phase. These results show that F127 microphases affect both the kinetics of GSNO photodecomposition and the rate of NO escape and can be used to modulate the photochemical NO delivery from F127/GSNO solutions.

Phase behavior of cholesterol in mixtures with hypo- and hypercholesterolemic lipids.

Some lipidic bioactives are largely reported to present hypocholesterolemic effects, for example, oleic acid, α-tocopherol, and octacosanol, found in rice-bran, olive, and sunflower oils. In contrast, some saturated and trans-unsaturated lipids found in animal fats or partially hydrogenated oils have been associated with the opposite effect. However, the mechanisms in which these lipids act for lowering or increasing cholesterol are not fully understood. In this context, this work was aimed at a fundamental physicochemical comprehension of how cholesterol phase behavior is affected in mixtures with these compounds. The complete solid-liquid equilibrium (SLE) phase diagrams of these mixtures were depicted by differential scanning calorimetry and microscopy, and also evaluated by the SLE thermodynamic theory. The minimal melting temperature (eutectic points) of the mixtures followed the order: α-tocopherol < oleic acid < elaidic acid < stearic acid < octacosanol. Among all biocompounds, stearic and trans-oleic acids promoted few changes in the normal thermodynamic behavior of cholesterol when in a mixture. In contrast, α-tocopherol induced a significant temperature depression in the system. Furthermore, at high concentrations of cholesterol (>90% molar fraction), the formation of solid solution was observed in all other systems, to a higher degree for oleic acid. The higher interactions of these beneficial compounds and the formation of solid solution that literature associates with the alteration of cholesterol enteric absorption probably correlates with their hypocholesterolemic effects.

Simultaneous determination of six quality parameters of biodiesel through 1H NMR spectroscopy and partial least squares.

Biodiesel quality is checked by determining several parameters. Considering the large number of analyses in this verification, as well as the disadvantages of the use of toxic solvents and waste generation, multivariate calibration is suggested to reduce the number of tests. In this work, hydrogen nuclear magnetic resonance (1H NMR) spectra were used to build multivariate models, from partial least squares (PLS), in order to perform simultaneous determination of six important quality parameters of biodiesel: density at 20°C, kinematic viscosity at 40°C, iodine value, acid number, oxidative stability, and water content. 1H NMR spectrum reflects the structures of the compounds present in biodiesel and showed suitable correlations with the six parameters. In addition, the models were appropriate to predict all parameters for external samples. Thus, the alliance between 1H NMR spectra and PLS was shown to be applicable to extract a lot of information about biodiesel quality, significantly reducing analysis time, reagent and solvent consumption, and waste generation.

Alternative method to quantify biodiesel and vegetable oil in diesel-biodiesel blends through 1H NMR spectroscopy.

An alternative method is proposed for the quantitative analysis of biodiesel in diesel-biodiesel blends. It is based on hydrogen nuclear magnetic resonance (1H NMR) spectroscopy and applies univariate calibration, in which the integrals of the spectra are considered. Statistical comparisons between the results obtained from the method proposed here and from the infrared (IR) spectrometry method, which is recommended by the European Standard EN 14078, show that the 1H NMR method offers equivalent results compared with standard ones. Furthermore, the proposed 1H NMR method recognizes the difference between biodiesel and vegetable oil, whereas the IR method cannot. Therefore, the 1H NMR method developed to quantify biodiesel in diesel-biodiesel blends is proposed here as a more practical and efficient alternative to the official method, because besides quantifying biodiesel in blends, it indicates adulteration with vegetable oil, either as the intentional and illegal addition of this raw material or because of a low degree of transesterification conversion during biodiesel synthesis.