Abstract Haemophilus influenzae type b is an important human pathogen causing several invasive diseases in children under five years of age, against which glycoconjugated vaccines based on polyribosylribitol phosphate have been licensed. Quimi-Hib ® is the first and only vaccine against this pathogen using the polysaccharide obtained by chemical synthesis. The Active Pharmaceutical Ingredient is produced by the Center for Genetic Engineering and Biotechnology and is obtained from its conjugation to tetanus toxoid. In the present report, a characterization of polyribosylribitol phosphate was performed using the high performance molecular exclusion chromatography technique with ultraviolet detection at 215 nm. Three batches were evaluated in the study and the elution profile was determined on a Superdex TM 75 10/300 GL Increase column with a purity percent of 77.42 ± 8.97 and an average molar mass of 7, 381 Da ± 210.93. The main impurity present in polyribosylribitol phosphate is dimethyl sulfoxide, the solvent used in the activation reaction with the N-hydroxysuccinimidyl ester of β-maleimidopropionic acid. The polyribosylribitol phosphate was purified by filtration with a 2, 000 Da Amicon Ultra-15 to 99.1% purity and conjugated to tetanus toxoid. The yield of the conjugation reaction with the purified polysaccharide was 30.0% ± 1.77 which shows no significant difference with the control which was 33.7% ± 3.57 demonstrating that dimethyl sulfoxide does not affect the performance of the conjugation reaction.

Abstract Cyclosporine A and sirolimus are immunosuppressants that are widely used in many organ transplantation procedures. They exhibit some complementary mechanisms of action and interact synergistically when used together. However, they are critical⁃dose drugs and have a narrow therapeutic index. They provide the desired therapeutic effect with acceptable tolerability only within a specific range of blood concentrations. Therefore, the rapid and simultaneous detection of the concentrations of cyclosporine A and sirolimus in whole blood could provide valuable information on planning medicine administration after organ transplantations. In this study, firstly, the chromatographic behaviors of cyclosporine A and sirolimus on a biological liquid chromatography (BioLC)column and traditional liquid chromatography (TraLC)columns were investigated systematically under the same chromatographic conditions. The results suggested that the peak height and peak width of cyclosporine A and sirolimus on the BioLC column, ZORBAX 300SB C8 (250 mm X 4.6 mm, 5.0 μ m), were the highest and narrowest, respectively. The number of theoretical plates of cyclosporine A and sirolimus on the ZORBAX 300SB C8 column increased significantly when the volume ratio of acetonitrile in the mobile phases was greater than 70%. Their retention time on the BioLC and TraLC columns was negligibly affected by the use of formic acid and trifluoroacetic acid as the mobile phases. In the range of the experimental column temperature, the number of theoretical plates of cyclosporine A and sirolimus on the ZORBAX 300SB C8 column was significantly higher than that on the two TraLC columns. Furthermore, the relationship between the retention factor and column temperature of cyclosporine A on the ZORBAX 300SB C8 column was different from that on the two TraLC columns. A sample of whole blood with a volume of 50 μL was prepared by protein precipitation with 1 mol/L sodium hydroxide and then extracted into 500 μL of ether⁃methanol (95:5, v/v). After centrifugation at 14.000 r/min for 10 min, the organic layer was removed and evaporated under a stream of nitrogen at 50 ℃. The residue was then reconstituted in 200 μL of methanol for use. Cyclosporin A and sirolimus were separated through isocratic elution on the ZORBAX 300SB C8 column.

Abstract The estimation of the chemical and bromatological composition of foods involves a series of studies that evaluate mainly the fiber fraction, since it presents great variability when compared to the other components. The growing number of publications on the analytical techniques available for determining the nutritional value of foods end up generalizing the use of ill-defined terms. There are several techniques for evaluating forage components, the detergent system being the most widely used, although there are more modern methods. However, the accessibility and cost of these modern methods are factors that limit their use in many laboratories. Furthermore, some of these methods are not recognized as official methods of analysis. In this context, the objectives of this review were: to highlight the most important concepts in the determination of the nutritional value of foods; to improve the use and the difficulties of interpretation of the analytical results. It was concluded that the use of analytical methods allows the estimation of the composition and the availability of the different fractions of the cell wall. But variability of the cell wall constituents requires knowledge of the different analytical methodologies available. The analytical methods, traditional or alternative, are still empirical since they present different results for the same analysis. These variations are generated most of the time by the differences between the steps of the analytical procedures. It is clear that the improvement of analytical methods is of paramount importance to estimate the nutritional value of foods.