Progress on the Development and Single-Laboratory Validation of a High-Performance Liquid Chromatographic Method for the Determination of Carbadox and Pyrantel Tartrate in Type B and C Medicated Feeds

Carbadox, an antimicrobial agent, and pyrantel tartrate, an anthelmintic, are feed additives that are often used in combination in the United States. The current AOAC methods for these analytes are spectrophotometric, using standard addition techniques. These methods are labor-intensive and prone to variability as well as matrix interferences. Published methods for both analytes that use high-performance liquid chromatography were evaluated and a test method was developed. The method uses a water prewetting step to enhance extraction of pyrantel followed by extraction with acetonitrileethanol (50 + 50). Sample extracts are filtered through a glass fiber filter and purified using alumina solid-phase extraction columns. Chromatography is performed on a C18 column with a gradient mobile phase of dibutylamine acetate and acetonitrile. The data show that both analytes exhibit acceptable peak shape when a C18 column that is both acid- and base-deactivated is used. Linearity has been established and initial recovery studies on medicated swine feeds are promising.

Content of Glutathione and Vitamin C in the Liver of Rats Exposed to Dimethoate and Pyrantel Tartrate

The study was undertaken to examine the effect of oral administration of dimethoate (Bi 58 Nowy) and/or pyrantel tartrate on the concentration of glutathione (GSH) and vitamin C in rat liver. Rats of Group I were administered pyrantel tartrate at a dose of 85 mg/kg b.w. at a twoweek interval, while the animals of Group II received Bi 58 Nowy (38% dimethoate) at a dose of 25 mg/kg b.w. for 28 days, and animals of Group III received both compounds together as described above. Pyrantel tartrate was found to increase the concentration of glutathione in the liver, whereas the content of vitamin C oscillated around values reported for the control. After a 28-day exposure to dimethoate (Bi 58 Nowy), except for the 6th hour after intoxication, the content of GSH was observed to increase and significant differences (p ≤ 0.05) occurred after days 3 and 14 (p ≤ 0.01). The concentration of vitamin C in liver homogenates after dimethoate administration was decreased compared to the control until day 3. An increase was then observed continuing until the end of the experiment. In animals receiving both compounds, except for day 7, the concentration of vitamin C was slightly decreased. The administration of pyrantel tartrate before dimethoate (Bi 58 Nowy) only in some time intervals was found to reduce the intensity of changes evoked by the exclusive administration of insecticide. It may suggest that not in all cases of mixed intoxications, intensification should be expected in changes of the variables analyzed.