Determination by capillary zone electrophoresis of berenil, phenamidine, diampron and dibromopropamidine in serum and urine.

A quick, simple and reliable analysis method has been developed in order to determine berenil, phenamidine, diampron and dibromopropamidine by capillary zone electrophoresis in samples of serum and urine. In order to define the operation parameters in CZE, we have carried out a study on how the apparent electrophoretic mobility (mu(app)) varies when pH, buffer concentration, voltage and temperature are modified. Ohm's law plot has been studied, too. With the data obtained from this study we have determined the optimum work conditions, which are: citrate buffer 25 mM, pH=3.70, 14 kV, 30 degrees C, wavelength of the UV detector: 200 nm, capillary tube: 570 mm x 75 microm. Under these conditions, all the products appear in times between: 7.6 min phenamidine and 8.8 min dibromopropamidine, limits of detection being: berenil: 0.50, phenamidine: 0.25, diampron: 0.40 and dibromopropamidine: 0.80 microg ml(-1). We have carried out a recovery study with three kinds of extraction cartridges: Sep-pak C-18 plus, Sep-pak C-8 plus and Oasis HBL for each one of the products in blood and urine.

Studies in cattle on the disposition of the anti-trypanosomal drug diminazene diaceturate (Berenil).

After intramuscular injection of ca. 3.5 mg kg-1 diminazene diaceturate-(bis-phenyl-U-14C) to two healthy male calves weighing 185 and 180 kg, levels of radioactivity were determined in blood, plasma, urine, faeces, and in edible tissues. The maximal blood level of 4.6 micrograms and 4.7 micrograms equivalents of diminazene diaceturate ml-1 (calculated from total radioactivity) occurred 15 min (calf C1) and 45 min (calf C2) after administration. The decrease in concentration followed a biphasic process with half lives of 2 and 188 hours. Seven days after treatment 47.1% of the dose had been excreted in the urine and 7.1% in the faeces. The respective values were 72.2% and 10.3% after 20 days. The half lives were similar to those in blood. The main product in urine was unchanged diminazene. Distribution studies showed concentrations which were low in general in edible tissues, i.e. in skeletal musculature and fat (below 1 microgram equivalent g-1), but higher in organs with excretory functions. There were 75.5 micrograms equivalents g-1, corresponding to 22% of the dose, in the liver 7 days after injection. This had decreased to 24.4 micrograms equivalents g-1, corresponding to 15% of the dose, at day 20. Only unchanged deminazene was detected in the liver extracts by thin-layer chromatography. Relay-bioavailability studies showed that the total liver residues were only partially available (mean = 23% of the dose) when fed to rats.