Quantitative determination of glufosinate in biological samples by liquid chromatography with ultraviolet detection after p-nitrobenzoyl derivatization.
We have established a new HPLC method for derivatizing and quantifying glufosinate (GLUF) in human serum and urine using p-nitrobenzoyl chloride (PNBC). The p-nitrobenzoyl derivative of GLUF (PNB-GLUF) was produced quantitatively over 10 min at room temperature. PNB-GLUF possesses the property of ultraviolet (UV) light absorption with a lambda(max) of 272.8 nm, and was isolated from biological specimens by reversed-phase chromatography using Inertsil Ph-3. In experiments at a UV wavelength of 273 nm, GLUF has a quantitative detection limit of 0.005 microg/ml, and when it was added to both serum and urine to yield concentrations of 0.1-1000 microg/ml, its recovery rate was quite satisfactory: at least 93.8% in all cases. Further, the measured amounts of GLUF in 23 serum samples from patients intoxicated by ingestion of GLUF compared favorably with those obtained by fluorescence derivatization-HPLC using 9-fluorenylmethyl chloroformate (R=0.998). This technique of analysis is, in addition, applicable for Glyphosat, which possesses a chemical structure resembling that of GLUF, and it will be of great use in the determination of these two compounds.
Protein binding of glufosinate and factors affecting it revealed by an equilibrium dialysis technique.
We investigated the protein binding of glufosinate ammonium (GLF) and several factors affecting this binding using human serum albumin (HSA) and human volunteer serum under various conditions. The mean ratios of the free GLF (RFr-GLF) to 4% HSA were examined in the sera of patients described elsewhere at GLF levels from 1 microg/mL to 500 microg/mL; the range was found to be only from 0.80 to 0.88. Neither the incubation temperature nor buffers containing different chloride ion concentrations had any effect on the RFr-GLF to HSA. Moreover, the addition of heparin, glycoprotein-alpha1-acid (AAG), and sodium azide had no effect on the RFr-GLF. However, pH of the isotonic phosphate buffer and the addition of palmitic or oleic acid were seen to have an effect. In this study, the mean RFr-GLF to healthy human serum was 0.99. This high value was evidenced that GLF was rapidly excreted through the renal route.
Circulatory failure caused by a fungicide containing iminoctadine and a surfactant: a pharmacological analysis in rats.
The fungicide Befran (BFR), containing iminoctadine as an active ingredient and polyoxyethylene alkylether (POEAE) as a surfactant, has been known to cause circulatory failure in human acute oral poisoning. We investigated separately the effects of iminoctadine, POEAE, and BFR on heart rate and blood pressure of rats and also on isolated atria and aortas. In isolated rat atria, iminoctadine produced positive chronotropic and inotropic responses. In contrast, POEAE produced negative chronotropic and inotropic responses. BFR produced no effects at low concentrations, but significant negative chronotropic and inotropic responses at high concentrations. In isolated rat aortas, iminoctadine produced remarkable vasodilative responses, but POEAE produced vasoconstrictive responses. BFR produced both vasodilative and vasoconstrictive responses. When intravenously administered to anesthetized rats, iminoctadine produced hypotension and tachycardia in a dose-dependent manner. POEAE produced significant hypotension and slight bradycardia. BFR, at low doses, produced hypotension without elevation of heart rate. At high doses, it produced significant hypotension and tachycardia. From these results, it can be concluded that severe hypotension induced by BFR is due mainly to the vasodilative effect of iminoctadine and partly to the cardio-suppressive effect of POEAE.