The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform
Mark O Barnett - One of the best experts on this subject based on the ideXlab platform.
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fate and transport of sulfadimethoxine and Ormetoprim in two southeastern united states soils
Vadose Zone Journal, 2009Co-Authors: Puneet Srivastava, S M Sanders, Yucheng Feng, J H Dane, J Basile, Mark O BarnettAbstract:There have been increasing concerns regarding antimicrobial contaminants in the environment. To date, limited research exists regarding the fate and transport of these compounds in the environment once they have been discharged in human and animal wastes. The fate and transport of two antimicrobials, sulfadimethoxine (SDM) and Ormetoprim (OMP), were investigated in two soils and a sand using miscible pulse and step displacement column studies. Because OMP and SDM are often administered in combination, their fate and transport were investigated individually as single solutes as well as in combination as cosolutes. The transport of SDM and OMP was modeled by the chemical nonequilibrium model of the convection–dispersion equation. Sorption of SDM in soils and sand was found to be weak (i.e., it readily desorbed); OMP was sorbed more strongly and required more time for desorption. Results for the pulse input columns yielded mass recoveries >0.90 for the sand and two soils with SDM and for the sand with OMP. Mass recoveries of OMP in the two soils were 0.56 and 0.55, respectively, indicating irreversible sorption or chemical transformation. Comparisons of single-solute and cosolute column studies of OMP and SDM indicate that sorption and transport of these compounds in mixtures were not considerably different from their individual sorption and transport. Overall, the results from this study indicate that both compounds have the potential to move through soils, contaminating nearby surface waters and groundwater.
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sorption of the veterinary antimicrobials sulfadimethoxine and Ormetoprim in soil
Journal of Environmental Quality, 2008Co-Authors: S M Sanders, Puneet Srivastava, Yucheng Feng, J H Dane, J Basile, Mark O BarnettAbstract:: Currently, limited research on the fate of antimicrobials in the environment exists, once they are discharged in human and animal wastes. Sorption of two antimicrobials, sulfadimethoxine (SDM) and Ormetoprim (OMP), was investigated in two soils and sand using a series of batch experiments. Because OMP and SDM are often administered in combination, their sorption was also investigated in combination as co-solutes. The rate of SDM and OMP sorption was rapid over the first few hours of the experiments, which then slowed considerably after 16 to 68 h. OMP sorption was enhanced at high concentrations when in combination with SDM, with linear sorption coefficients ranging from 1.3 to 58.3 L.kg(-1) in the single solute experiments and 4.96 to 89.7 L.kg(-1) in the co-solute experiments. Sorption of OMP as a single solute seems to provide a better fit with the Freundlich equation, which became more linear (n approached 1) when SDM was present. Overall, SDM sorbed less than OMP in the two soils and sand. SDM linear sorption coefficients ranged from 0.4 to 25.8 L.kg(-1) as a single solute and 2.5 to 22.1 L.kg(-1) as a co-solute. Sorption of SDM becomes more nonlinear (n < 1) when SDM is present in combination with OMP. Overall, sorption of both antimicrobials increased in the selected soils and sand as the organic matter, clay content, and cation exchange capacity increased. These experiments indicate relatively low sorption of SDM and OMP in natural soils, making them a potential threat to surface and ground water.
S M Sanders - One of the best experts on this subject based on the ideXlab platform.
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fate and transport of sulfadimethoxine and Ormetoprim in two southeastern united states soils
Vadose Zone Journal, 2009Co-Authors: Puneet Srivastava, S M Sanders, Yucheng Feng, J H Dane, J Basile, Mark O BarnettAbstract:There have been increasing concerns regarding antimicrobial contaminants in the environment. To date, limited research exists regarding the fate and transport of these compounds in the environment once they have been discharged in human and animal wastes. The fate and transport of two antimicrobials, sulfadimethoxine (SDM) and Ormetoprim (OMP), were investigated in two soils and a sand using miscible pulse and step displacement column studies. Because OMP and SDM are often administered in combination, their fate and transport were investigated individually as single solutes as well as in combination as cosolutes. The transport of SDM and OMP was modeled by the chemical nonequilibrium model of the convection–dispersion equation. Sorption of SDM in soils and sand was found to be weak (i.e., it readily desorbed); OMP was sorbed more strongly and required more time for desorption. Results for the pulse input columns yielded mass recoveries >0.90 for the sand and two soils with SDM and for the sand with OMP. Mass recoveries of OMP in the two soils were 0.56 and 0.55, respectively, indicating irreversible sorption or chemical transformation. Comparisons of single-solute and cosolute column studies of OMP and SDM indicate that sorption and transport of these compounds in mixtures were not considerably different from their individual sorption and transport. Overall, the results from this study indicate that both compounds have the potential to move through soils, contaminating nearby surface waters and groundwater.
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sorption of the veterinary antimicrobials sulfadimethoxine and Ormetoprim in soil
Journal of Environmental Quality, 2008Co-Authors: S M Sanders, Puneet Srivastava, Yucheng Feng, J H Dane, J Basile, Mark O BarnettAbstract:: Currently, limited research on the fate of antimicrobials in the environment exists, once they are discharged in human and animal wastes. Sorption of two antimicrobials, sulfadimethoxine (SDM) and Ormetoprim (OMP), was investigated in two soils and sand using a series of batch experiments. Because OMP and SDM are often administered in combination, their sorption was also investigated in combination as co-solutes. The rate of SDM and OMP sorption was rapid over the first few hours of the experiments, which then slowed considerably after 16 to 68 h. OMP sorption was enhanced at high concentrations when in combination with SDM, with linear sorption coefficients ranging from 1.3 to 58.3 L.kg(-1) in the single solute experiments and 4.96 to 89.7 L.kg(-1) in the co-solute experiments. Sorption of OMP as a single solute seems to provide a better fit with the Freundlich equation, which became more linear (n approached 1) when SDM was present. Overall, SDM sorbed less than OMP in the two soils and sand. SDM linear sorption coefficients ranged from 0.4 to 25.8 L.kg(-1) as a single solute and 2.5 to 22.1 L.kg(-1) as a co-solute. Sorption of SDM becomes more nonlinear (n < 1) when SDM is present in combination with OMP. Overall, sorption of both antimicrobials increased in the selected soils and sand as the organic matter, clay content, and cation exchange capacity increased. These experiments indicate relatively low sorption of SDM and OMP in natural soils, making them a potential threat to surface and ground water.
Jianyong Li - One of the best experts on this subject based on the ideXlab platform.
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simultaneous determination of diaveridine trimethoprim and Ormetoprim in feed using high performance liquid chromatography tandem mass spectrometry
Food Chemistry, 2016Co-Authors: Yajun Yang, Bing Li, Shihong Li, Xiaojun Kong, Jianyong LiAbstract:This study developed and validated a simple and reliable method for detecting and quantifying DVD, TMP and OMP in feed using dichloromethane extraction followed by HPLC-MS/MS. A matrix effect evaluation was performed using the post-extraction spiking method, and levels were less than ±15% in all three feeds with their corresponding concentrations. LOD and LOQ, CCα and CCβ were 20 μg kg−1 and 40 μg kg−1, 8.68–15.55 μg kg−1 and 10.61–18.92 μg kg−1 for all analytes, respectively. Calibration curves were linear for DVD, TMP and OMP with R2 ⩾ 0.990 and r ⩾ 0.995, respectively. Recoveries of low, medium and high concentrations using the proposed method ranged from 74.4 to 105.2%. Repeatability and within-laboratory reproducibility were <7.4% (RSD). The chosen seven factors had no a significant influence on robustness. The method showed good performance when it was applied to analyze other laboratory-prepared or actual feed samples.
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Simultaneous determination of diaveridine, trimethoprim and Ormetoprim in feed using high performance liquid chromatography tandem mass spectrometry.
Food Chemistry, 2016Co-Authors: Yajun Yang, Bing Li, Shihong Li, Xiaojun Kong, Jianyong LiAbstract:This study developed and validated a simple and reliable method for detecting and quantifying DVD, TMP and OMP in feed using dichloromethane extraction followed by HPLC-MS/MS. A matrix effect evaluation was performed using the post-extraction spiking method, and levels were less than ±15% in all three feeds with their corresponding concentrations. LOD and LOQ, CCα and CCβ were 20 μg kg−1 and 40 μg kg−1, 8.68–15.55 μg kg−1 and 10.61–18.92 μg kg−1 for all analytes, respectively. Calibration curves were linear for DVD, TMP and OMP with R2 ⩾ 0.990 and r ⩾ 0.995, respectively. Recoveries of low, medium and high concentrations using the proposed method ranged from 74.4 to 105.2%. Repeatability and within-laboratory reproducibility were
Michael K Stoskopf - One of the best experts on this subject based on the ideXlab platform.
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pharmacokinetics of sulfadimethoxine and Ormetoprim in a 5 1 ratio following intraperitoneal and oral administration in the hybrid striped bass morone chrysops morone saxitalis
Journal of Veterinary Pharmacology and Therapeutics, 2004Co-Authors: R S Bakal, Michael K StoskopfAbstract:: Selected pharmacokinetic parameters for sulfadimethoxine and Ormetoprim, administered in a 5:1 ratio, via the oral and intraperitoneal (i.p.) routes were determined in the hybrid striped bass (Morone chrysops x Morone saxitalis). Plasma concentrations of both drugs were determined by high-performance liquid chromatography. A first-order one-compartment model adequately described plasma drug disposition. The elimination half-lives for sulfadimethoxine following i.p. and oral administration were 26 and 10.5 h, respectively. The half-lives for Ormetoprim administered via i.p. and oral routes were 7.5 and 3.9 h, respectively. Cmax for sulfadimethoxine via the i.p. and oral routes were calculated to be 27.7 (+/-9.0) microg/mL at 3.6 h and 3.2 (+/-1.2) microg/mL at 1.2 h, respectively. Cmax for Ormetoprim via the i.p. route was calculated to be 1.2 (+/-0.5) microg/mL at 9.1 h and 1.58 (+/-0.7) microg/mL at 5.7 h for the oral route. The oral availability of sulfadimethoxine relative to the i.p. route was 4.6%, while the oral availability of Ormetoprim relative to the i.p. route was 78.5%. Due to the nonconstant ratio of these drugs in the plasma of the animal, the actual drug ratio to use for determining minimum inhibitory concentration (MIC) is unclear. Using the ratio of the total amount of each drug that is absorbed as a surrogate for the mean actual ratio may be the best alternative to current methods. Using this ratio as determined in these studies, (2.14:1 sulfadimethoxine:Ormetoprim) to determine the MICs the single 50 mg/kg oral dose of the 5:1 combination of sulfadimethoxine and Ormetoprim appears to provide plasma concentrations high enough to inhibit the growth of Yersinia ruckeri, Edwardsiella tarda, and Escherichia coli.
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in vitro studies of the fate of sulfadimethoxine and Ormetoprim in the aquatic environment
Aquaculture, 2001Co-Authors: R S Bakal, Michael K StoskopfAbstract:Abstract These studies showed sulfadimethoxine and Ormetoprim to be stable at salinities of 0 and 30 ppt and at pHs of 2, 7, and 12 for a period of 1 year. Sulfadimethoxine was stable at 25°C and 37°C, but showed a marked decrease in concentration at 4°C. Warming of the 4°C sample resulted in a return to original drug levels indicating that the drug had redistributed out of the aquatic phase at the lower temperature. Ormetoprim concentrations were stable at all temperatures evaluated. The concentrations of both sulfadimethoxine and Ormetoprim were unaffected by the presence of silica sand, high density poly-ethylene, or poly-vinyl chloride. The presence of bentonite clay caused a reduction in Ormetoprim concentrations while sulfadimethoxine was unchanged by this substrate. Acidification of the sample containing the bentonite clay resulted in a return of Ormetoprim concentration to original levels. From these studies, it is apparent that the potential environmental half-lives for these drugs must exceed 1 year and are likely to be several years in duration.
Puneet Srivastava - One of the best experts on this subject based on the ideXlab platform.
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fate and transport of sulfadimethoxine and Ormetoprim in two southeastern united states soils
Vadose Zone Journal, 2009Co-Authors: Puneet Srivastava, S M Sanders, Yucheng Feng, J H Dane, J Basile, Mark O BarnettAbstract:There have been increasing concerns regarding antimicrobial contaminants in the environment. To date, limited research exists regarding the fate and transport of these compounds in the environment once they have been discharged in human and animal wastes. The fate and transport of two antimicrobials, sulfadimethoxine (SDM) and Ormetoprim (OMP), were investigated in two soils and a sand using miscible pulse and step displacement column studies. Because OMP and SDM are often administered in combination, their fate and transport were investigated individually as single solutes as well as in combination as cosolutes. The transport of SDM and OMP was modeled by the chemical nonequilibrium model of the convection–dispersion equation. Sorption of SDM in soils and sand was found to be weak (i.e., it readily desorbed); OMP was sorbed more strongly and required more time for desorption. Results for the pulse input columns yielded mass recoveries >0.90 for the sand and two soils with SDM and for the sand with OMP. Mass recoveries of OMP in the two soils were 0.56 and 0.55, respectively, indicating irreversible sorption or chemical transformation. Comparisons of single-solute and cosolute column studies of OMP and SDM indicate that sorption and transport of these compounds in mixtures were not considerably different from their individual sorption and transport. Overall, the results from this study indicate that both compounds have the potential to move through soils, contaminating nearby surface waters and groundwater.
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sorption of the veterinary antimicrobials sulfadimethoxine and Ormetoprim in soil
Journal of Environmental Quality, 2008Co-Authors: S M Sanders, Puneet Srivastava, Yucheng Feng, J H Dane, J Basile, Mark O BarnettAbstract:: Currently, limited research on the fate of antimicrobials in the environment exists, once they are discharged in human and animal wastes. Sorption of two antimicrobials, sulfadimethoxine (SDM) and Ormetoprim (OMP), was investigated in two soils and sand using a series of batch experiments. Because OMP and SDM are often administered in combination, their sorption was also investigated in combination as co-solutes. The rate of SDM and OMP sorption was rapid over the first few hours of the experiments, which then slowed considerably after 16 to 68 h. OMP sorption was enhanced at high concentrations when in combination with SDM, with linear sorption coefficients ranging from 1.3 to 58.3 L.kg(-1) in the single solute experiments and 4.96 to 89.7 L.kg(-1) in the co-solute experiments. Sorption of OMP as a single solute seems to provide a better fit with the Freundlich equation, which became more linear (n approached 1) when SDM was present. Overall, SDM sorbed less than OMP in the two soils and sand. SDM linear sorption coefficients ranged from 0.4 to 25.8 L.kg(-1) as a single solute and 2.5 to 22.1 L.kg(-1) as a co-solute. Sorption of SDM becomes more nonlinear (n < 1) when SDM is present in combination with OMP. Overall, sorption of both antimicrobials increased in the selected soils and sand as the organic matter, clay content, and cation exchange capacity increased. These experiments indicate relatively low sorption of SDM and OMP in natural soils, making them a potential threat to surface and ground water.