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Reconstructing organophosphorus pesticide doses using the reversed dosimetry approach in a simple physiologically-based pharmacokinetic model.

Lu C, Andres L - J Toxicol (2012)

Bottom Line: The dose estimates resulting from the first morning voids appeared to be lower than but not significantly different to those using before bedtime, lunch or dinner voids.We found similar trend for dose estimates using three different urinary composite data.However, the dose estimates using the SPK model for individual children were significantly higher than those from the conventional physiologically based pharmacokinetic (PBPK) modeling using aggregate environmental measurements of chlorpyrifos as the model inputs.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Health, Harvard School of Public Health, 401 Park Drive, Boston, MA 02215, USA.

ABSTRACT
We illustrated the development of a simple pharmacokinetic (SPK) model aiming to estimate the absorbed chlorpyrifos doses using urinary biomarker data, 3,5,6-trichlorpyridinol as the model input. The effectiveness of the SPK model in the pesticide risk assessment was evaluated by comparing dose estimates using different urinary composite data. The dose estimates resulting from the first morning voids appeared to be lower than but not significantly different to those using before bedtime, lunch or dinner voids. We found similar trend for dose estimates using three different urinary composite data. However, the dose estimates using the SPK model for individual children were significantly higher than those from the conventional physiologically based pharmacokinetic (PBPK) modeling using aggregate environmental measurements of chlorpyrifos as the model inputs. The use of urinary data in the SPK model intuitively provided a plausible alternative to the conventional PBPK model in reconstructing the absorbed chlorpyrifos dose.

No MeSH data available.


Related in: MedlinePlus

The dose estimates (CPF_DOSE, μg/kg/day) for chlorpyrifos using 3,5,6-trichlorpyridinol concentrations in the spot urine samples collected at before bedtime in Day 1 and the first morning, lunch, and dinner voids in Day 2 as the SPK model inputs.
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fig2: The dose estimates (CPF_DOSE, μg/kg/day) for chlorpyrifos using 3,5,6-trichlorpyridinol concentrations in the spot urine samples collected at before bedtime in Day 1 and the first morning, lunch, and dinner voids in Day 2 as the SPK model inputs.

Mentions: The SPK model simulation yielded to a total of 88 CPF dose estimates, separated by summer and fall seasons. The dose estimates resulted from the first morning void measurements appeared to be lower than but not significantly different to those using before bedtime, lunch, or dinner voids (Figure 2). Those estimates were modeled assuming that the exposure to CPF occurred during dinner meal (at 7 pm) on the first day. Knowing that the biological half-life for orally ingested CPF is approximately 16 hours [23], the estimated absorption curve for the first morning void may mostly reflect the intake of CPF from dinner last night. Dose estimates for spot urine samples collected later in the 2nd day were increasingly larger, suggesting additional CPF exposures from earlier in the day (breakfast and lunch). Dose estimates from before bedtime void samples were likely to be representative of CPF exposures that occurred throughout the first day rather than intakes from dinner, as was modeled.


Reconstructing organophosphorus pesticide doses using the reversed dosimetry approach in a simple physiologically-based pharmacokinetic model.

Lu C, Andres L - J Toxicol (2012)

The dose estimates (CPF_DOSE, μg/kg/day) for chlorpyrifos using 3,5,6-trichlorpyridinol concentrations in the spot urine samples collected at before bedtime in Day 1 and the first morning, lunch, and dinner voids in Day 2 as the SPK model inputs.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3306923&req=5

fig2: The dose estimates (CPF_DOSE, μg/kg/day) for chlorpyrifos using 3,5,6-trichlorpyridinol concentrations in the spot urine samples collected at before bedtime in Day 1 and the first morning, lunch, and dinner voids in Day 2 as the SPK model inputs.
Mentions: The SPK model simulation yielded to a total of 88 CPF dose estimates, separated by summer and fall seasons. The dose estimates resulted from the first morning void measurements appeared to be lower than but not significantly different to those using before bedtime, lunch, or dinner voids (Figure 2). Those estimates were modeled assuming that the exposure to CPF occurred during dinner meal (at 7 pm) on the first day. Knowing that the biological half-life for orally ingested CPF is approximately 16 hours [23], the estimated absorption curve for the first morning void may mostly reflect the intake of CPF from dinner last night. Dose estimates for spot urine samples collected later in the 2nd day were increasingly larger, suggesting additional CPF exposures from earlier in the day (breakfast and lunch). Dose estimates from before bedtime void samples were likely to be representative of CPF exposures that occurred throughout the first day rather than intakes from dinner, as was modeled.

Bottom Line: The dose estimates resulting from the first morning voids appeared to be lower than but not significantly different to those using before bedtime, lunch or dinner voids.We found similar trend for dose estimates using three different urinary composite data.However, the dose estimates using the SPK model for individual children were significantly higher than those from the conventional physiologically based pharmacokinetic (PBPK) modeling using aggregate environmental measurements of chlorpyrifos as the model inputs.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Health, Harvard School of Public Health, 401 Park Drive, Boston, MA 02215, USA.

ABSTRACT
We illustrated the development of a simple pharmacokinetic (SPK) model aiming to estimate the absorbed chlorpyrifos doses using urinary biomarker data, 3,5,6-trichlorpyridinol as the model input. The effectiveness of the SPK model in the pesticide risk assessment was evaluated by comparing dose estimates using different urinary composite data. The dose estimates resulting from the first morning voids appeared to be lower than but not significantly different to those using before bedtime, lunch or dinner voids. We found similar trend for dose estimates using three different urinary composite data. However, the dose estimates using the SPK model for individual children were significantly higher than those from the conventional physiologically based pharmacokinetic (PBPK) modeling using aggregate environmental measurements of chlorpyrifos as the model inputs. The use of urinary data in the SPK model intuitively provided a plausible alternative to the conventional PBPK model in reconstructing the absorbed chlorpyrifos dose.

No MeSH data available.


Related in: MedlinePlus