Anthocyanin degradation of blueberry-aronia nectar in glass compared with carton during storage.

Blueberry-aronia nectar is known as a rich source of anthocyanins, which are mostly destroyed during commercial storage of the product. The factors influencing the rate of degradation are connected to the oxygen protection offered by the packaging, as well as the type of anthocyanidin and the amount of glycosylated sugar. The current study was aimed to compare the stability of total anthocyanin between glass and carton packaging as well as to determine the stability of individual anthocyanin with respect to aglycone and glycosylated sugar. The degradation rate of total anthocyanin degradation rate was 22% higher in carton packaging than glass bottle. The ranking order of the stability of individual anthocyanin with respect to aglycone was as follows (from the most to least stable): cyanindin > peonidin > petunidin > malvidin = delphinidin. The ranking order of the stability of anthocyanins with respect to glycosylated sugars was as follows (from the most to least stable): glucose > galactose > arabinose. As individual anthocyanins have different degradation rates this study can be used to determine the most stable natural colorant and the most sensitive antioxidant among the anthocyanins tested.

High-performance thin-layer chromatography method for monitoring norfloxacin residues on pharmaceutical equipment surfaces.

This paper presents a high-performance thin-layer chromatography (HPTLC) method with direct fluorescence measurement for the determination of norfloxacin. The method was validated for the monitoring of norfloxacin residues on stainless steel surfaces at the allowed limit of 10 mg of norfloxacin per square meter. However, it can be adapted for lower amounts of residues owing to the low detection limit of norfloxacin (about 5 ng) and can also be used for other surface materials. Test solutions were analyzed by the new HPTLC method and the known HPLC method for comparison. Accuracy and precision of the new HPTLC method, with a subsequent quantification by densitometer or video system, are comparable with those of the HPLC method.

Effects of early enteral nutrition on intestinal permeability and the development of multiple organ failure after multiple injury.

OBJECTIVE: To determine how immediate enteral nutrition (EN) affects gut permeability and the development of multiple organ failure (MOF) in multiply injured patients. DESIGN: Prospective, randomised clinical trial. SETTING: 20-bed surgical intensive care unit (ICU), university hospital. PATIENTS: 28 consecutive multiply injured patients, admitted in shock and stabilised in 6 h. INTERVENTIONS: Patients were randomly assigned to EN started not later than 6 h after admission to the ICU (group A), and to EN started later than 24 h after admission (group B). MEASUREMENTS AND MAIN RESULTS: The lactulose/mannitol (L/M) test was performed in patients on days 2 and 4 after trauma, and in 5 healthy volunteers. MOF scores were calculated daily. The mean MOF score from day 4 onwards was 1.84 in group A versus 2.81 in group B (p < 0.002), and was correlated with the time of initiation of EN after injury and the L/M ratio on day 2. The median L/M ratio on day 2 was 0.029 for group A and 0.045 for group B, while on day 4 it was 0.020 and 0.060, respectively. On day 2 after trauma, the L/M ratio was significantly higher in group B (p < 0.05) than in normal volunteers (median 0.014) and was positively correlated with the time of starting EN. CONCLUSIONS: In contrast with normal volunteers, the patients started on EN later than 24 h after admission to the ICU demonstrated increased intestinal permeability on the second day after sustaining multiple injury. Also, they had a more severe form of MOF than the group placed on EN immediately upon admission. However, early EN had no influence on the length of ICU stay or the time of mechanical ventilation.

Routine and sensitive method for determination of nicorandil in human plasma developed for liquid chromatography with ultraviolet and mass spectrometric detection.

A rapid and sensitive method using HPLC has been developed for the quantification of nicorandil (SG-75) in human plasma samples for routine bioequivalence studies. The sample preparation needs two liquid-liquid extractions, first with CH3Cl and HClO4 as denaturation reagent and second with addition of ethyl acetate and Na2CO3(aq). Detection wavelength was 256 nm. The obtained correlation coefficient for weighted linear curve in the range from 5.0 to 300 ng/ml was higher than 0.9950. The limit of quantitation (LOQ) was established at 5.0 ng/ml. The HPLC separation was accomplished on Nucleosil Phenyl (5 microm) stainless steel column within 7 min. The mixture of 0.01 M ammonium acetate buffer (pH 6.2) and acetonitrile 10:3 (v/v) was used as the mobile phase. The same separation method was examined on HPLC-MS system. Using this system, the LOQ was established at 1.0 ng/ml and the linearity was obtained in the range from 1.0 to 150 ng/ml.

High-performance thin-layer chromatographic separation of ranitidine hydrochloride and two related compounds.

Ranitidine hydrochloride and its two related compounds, used in the USP TLC purity testing of the drug, were separated on a high-performance thin-layer chromatography (HPTLC) RP-18 WF254S precoated plate using methanol-3% NH4OH (4:1, v/v) as the mobile phase. The main advantage of the proposed HPTLC system over the USP TLC system for testing the purity of ranitidine is a better and more efficient separation of these three compounds in a shorter time and with less consumption of solvents. The system is promising from the point of view of the development of a new method for the TLC purity testing of ranitidine hydrochloride. A video system was used for imaging thin-layer chromatograms. Direct UV densitometric quantitation of the three compounds and a model for the calculation of analytical performance parameters is presented in the second part of the paper.

Quantitative high-performance thin-layer chromatographic analysis of ampicillin in human urine.

A quantitative high-performance thin-layer chromatographic (HPTLC) method was developed for the analysis of ampicillin in urine. A dioxane-water-n-butanol-formic acid mobile phase system and HPTLC Silica gel 60 F254 as stationary phase were used. Quantitation was realized on a Zeiss PMQ 2 densitometer connected to a Varian A-25 recorder and an Apple II microcomputer or alternatively with an HP 9830A computer and HP 9862A plotter. A good linear range of detection (0.05-1.00 micrograms) at 480 nm was obtained. Standard statistical methods demonstrated good reproducibility (coefficient of variation is not greater than 3%). The method is appropriate for ampicillin quality control and pharmacokinetic studies.