The effect of oil as a dietary component on in vitro dissolution of an acid-labile drug.

The non-benzodiazepine-like anxiolytic agent deramiclane fumarate (EGIA-3886) was used to demonstrate that the presence of high oil/fat content in dissolution media serves as a barrier against accelerated drug degradation in acidic media.

Computerized comparison of the protein compositions of Erysipelothrix rhusiopathiae and Erysipelothrix tonsillarum strains.

Protein profiles of six Erysipelothrix rhusiopathiae strains, five Erysipelothrix tonsillarum strains and three Erysipelothrix strains of uncertain taxonomic position were studied by sodium dodecyl sulphate-polyactylamide gel electrophoresis (SDS-PAGE). In a computerized comparison of the protein patterns of the strains, the level of similarity between the strains was determined. The SDS-PAGE protein bands were divided into 14 groups based on molecular weight. The relative distribution of proteins within these groups was used to characterize the strains. These distribution patterns were analysed by computing Pearson's correlation coefficient between strains, and by cluster analysis based on Euclidean distances and the unweighted pair-group method of arithmetic averages (UPGMA). The geometric mean of the similarities calculated by Pearson's correlation coefficient was 0.980 +/- 0.018 between the E. rhusiopathiae strains and 0.979 +/- 0.013 for E. tonsillarum strains. The value was 0.932 +/- 0.036 between the strains belonging to different species. However, a threshold value applicable for identification of a given strain to a species could not be established. Of the three strains of uncertain taxonomic position, the strains designated Rotzunge and Iszap 4 had a protein composition more similar to that of E. tonsillarum than to that of the E. rhusiopathiae type strain. The strain designated Pécs 56, which may be a member of a new species according to literature data, gave inconsistent results by the two methods used. The computerized evaluation method developed here is suitable for the comparison of the protein composition of the strains and for the construction of the protein similarity tree by cluster analysis.

High-performance liquid chromatography column switching applied to the trace determination of herbicides in environmental and drinking water samples.

A selective and sensitive coupled-column high-performance liquid chromatographic method is developed for the simultaneous determination of 5 phenylurea herbicides (monuron, linuron, isoproturon, monolinuron, and diuron) in environmental and drinking water samples. Sample clean-up is performed automatically by means of a column switching technique. Using 2 octadecyl silica columns connected via two programmable 6-port valves and ultraviolet detection at 244 nm, the aforementioned compounds can be determined at the low concentration levels required for pesticide residue analysis in water samples. A mobile phase consisting of a mixture of methanol-water (55:45, v/v) is pumped at 1 mL/min. For the 5 phenylureas, high recoveries ranging from 94.9 to 101.6%, good reproducibility with relative standard deviations lower than 5%, and wide linear ranges up to 20 micrograms/L are observed with determination limits of 0.05 microgram/L. The method is successfully applied to the screening of different environmental water samples such as surface, ground, rain, and drinking water.

Computerized evaluation procedure for comparing the electrophoretic protein patterns of bacterial strains.

The advantages and drawbacks of different methods of evaluating electrophoretic (SDS-PAGE) protein patterns were studied by comparing Erysipelothrix rhusiopathiae strains. The computerized evaluation procedure recommended by the authors renders it possible to determine objectively the degree of similarity of the protein composition of the different strains according to molecular mass. The degree of similarity obtained in four parallel analyses of a given strain was 988 +/- 0.55 on a scale on which 1000 equals complete identity. the method can be used without adjustment even in those cases where the two strains to be compared contain unequal amounts of electrophoresed proteins.

Comparison of the protein composition of Erysipelothrix rhusiopathiae strains of subtype 1A isolated from ducks and pigs.

Erysipelothrix rhusiopathiae strains isolated from duck carcasses and pigs were examined by sodium dodecyl sulphate--polyacrylamide gel electrophoresis (SDS-PAGE) and the results were evaluated by a computerised method in order to compare the strains for protein composition according to molecular mass. To characterise the similarity of the strains, Pearson's correlation coefficient was calculated. The degree of similarity between duck strains originating from the same flock was 980-991, while that of strains isolated from ducks and pigs varied between 836 and 991 on a scale of 0 to 1000. The method gives highly reproducible results and can be utilised in epidemiological investigations. Its use may provide new data on E. rhusiopathiae strains, complementing the results of methods recommended for this purpose earlier and increasing the efficiency of epidemiological investigations.

Determination of fenbendazole, praziquantel and pyrantel pamoate in dog plasma by high-performance liquid chromatography.

Simple and rapid high-performance liquid chromatographic methods were developed for the determination of fenbendazole, praziquantel and pyrantel pamoate in dog plasma. The combination of these drugs is the most powerful treatment against most types of worms. Blood plasma samples obtained in a pharmacokinetic trial were prepared using solid-phase extraction. Fenbendazole and praziquantel were analyzed simultaneously by reversed-phase high-performance liquid chromatography on an octadecyl-modified silica stationary phase employing acetonitrile-phosphate buffer (pH 3.0) eluent and ultraviolet detection at 220 nm. Pyrantel was analyzed separately on a base-deactivated reversed-phase column using methanol-tetrahydrofuran-ammonium acetate buffer (pH 4.6) eluent and ultraviolet detection at 317 nm. Average recoveries for fenbendazole, praziquantel and pyrantel pamoate were 76.8, 93.4 and 90.5%, respectively. Limits of quantitation were in the range of 15-25 ng/ml plasma.

Comparison of the protein patterns of Erysipelothrix rhusiopathiae strains by SDS-PAGE and autoradiography.

The proteins of 12 Erysipelothrix rhusiopathiae strains were radiolabelled with L-[35S] methionine, and the protein fractions were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and autoradiography. The strains were found to differ from each other in their protein patterns; thus, it was concluded that the method applied could provide useful data for the identification of strains. The described procedure was used for determining the percentage contents of protein fractions of identical molecular mass within the strains compared. The results show that there is no significant correlation between the type of the strains and the percentage of identical molecular weight fractions.

Liquid chromatographic determination of the antibiotic fumagillin in fish meat samples.

A procedure for the determination of fumagillin, an antibiotic of Aspergillus fumigatus in fish meat samples, using reversed-phase high-performance liquid chromatography is described. Liquid chromatography was performed on an octadecylsilane column using acetonitrile-water-phosphoric acid solution as mobile phase, with detection at 350 nm. Two different types of sample preparation were developed, clean-up and enrichment, and the limits of quantification were 100 ng/g and 5 ng/g, respectively, in fish meat. The recovery was 75 +/- 3% in the concentration range 100-500 ng/g. To introduce the methodology and demonstrate its usefulness, a practical experiment was performed. Trouts fed with fumagillin were examined for elimination of fumagillin. After 24 h, the concentration was shown to decrease to below 100 ng/g.

Determination of oxytetracycline and its decomposition products in Tetran vulnerary powder.

A simple and fast HPLC method was developed for the determination of oxytetracycline and its decomposition products in pharmaceutical preparations. For this purpose an octadecyl modified silica stationary phase and a terner eluent containing aceto-nitrile-methanol-aqueous oxalic acid/EDTA solution was employed. Using this method, a stability study of oxytetracycline-containing powder was carried out. In this paper the analytical method and its performance data, the sample preparation and the obtained stability data are presented. The literature published on this topic is also shortly overviewed and discussed.