Metabolite analysis, isolation and purity assessment using various liquid chromatographic techniques combined with radioactivity detection.

During the discovery of metabolic routes of a drug candidate, radioactively labeled substances are administered. This study reports the multidimensional application of overpressured layer chromatography (OPLC) and high-performance liquid chromatography (HPLC) coupled with online or off-line nondestructive radioactivity detection methods in metabolism studies. Among these methods, digital autoradiography and flow-cell radioactivity detectors (RD) using solid scintillators are used.

Sorption behaviour of acetochlor, atrazine, carbendazim, diazinon, imidacloprid and isoproturon on Hungarian agricultural soil.

Laboratory studies were conducted to determine the sorption behaviour of six commonly used pesticides (acetochlor, atrazine, carbendazim, diazinon, imidacloprid and isoproturon) on Hungarian brown forest soil with clay alluviation (Luvisol) using the batch equilibrium technique. The sorption isotherms could be described by the Freundlich equation in non-linear form (n < 1) for all compounds, however in case of diazinon using the extended Freundlich equation proved to be a better approach. The adsorption constant related soil organic carbon content (Koc) calculated from Freundlich equation were 314 for acetochlor, 133 for atrazine, 2805 for carbendazim, 1589 for diazinon, 210 for imidacloprid and 174 for isoproturon.

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.