Development and Validation of an Analytical Method for Quantitation of Monobutylphthalate, a Metabolite of Di-n-Butylphthalate, in Rat Plasma, Amniotic Fluid, Fetuses and Pups by UPLC-MS/MS (original) (raw)
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Toxicology, 2006
Two studies were designed to examine amniotic fluid and maternal urine concentrations of the di(2-ethylhexyl) phthalate (DEHP) metabolite mono(2-ethylhexyl) phthalate (MEHP) and the din -butyl phthalate (DBP) metabolite monobutyl phthalate (MBP) after administration of DEHP and DBP during pregnancy. In the first study, pregnant Sprague-Dawley rats were administered 0, 11, 33, 100, or 300 mg DEHP/kg/day by oral gavage starting on gestational day (GD) 7. In the second study, DBP was administered by oral gavage to pregnant Sprague-Dawley rats at doses of 0, 100, or 250 mg/kg/day starting on GD 13. Maternal urine and amniotic fluid were collected and analyzed to determine the free and glucuronidated levels of MEHP and MBP. In urine, MEHP and MBP were mostly glucuronidated. By contrast, free MEHP and free MBP predominated in amniotic fluid. Statistically significant correlations were found between maternal DEHP dose and total maternal urinary MEHP (p = 0.0117), and between maternal DEHP dose and total amniotic fluid MEHP levels (p = 0.0021). Total maternal urinary MEHP and total amniotic fluid MEHP levels were correlated (Pearson correlation coefficient = 0.968). Statistically significant differences were found in amniotic MBP levels between animals within the same DBP dose treatment group (p < 0.0001) and between animals in different dose treatment groups (p < 0.0001). Amniotic fluid MBP levels increased with increasing DBP doses, and high variability in maternal urinary levels of MBP between rats was observed. Although no firm conclusions could be drawn from the urinary MBP data, the MEHP results suggest that maternal urinary MEHP levels may be useful surrogate markers for fetal exposure to DEHP.
Journal of Chromatography B, 2004
Concentrations of mono(2-ethylhexyl)phthalate (MEHP), and di(2-ethylhexyl)phthalate (DEHP), in serum of healthy volunteers were determined by high performance liquid chromatography (HPLC) with tandem mass spectrometry (LC/MS/MS). The serum was extracted with acetone, followed by hexane extraction under acidic conditions, and then applied to the LC/MS/MS. Recoveries of 20 ng/ml of MEHP and DEHP were 101 ± 5.7 (n = 6) and 102 ± 6.5% (n = 6), respectively. The limits of quantification (LOQ) of MEHP and DEHP in the method were 5.0 and 14.0 ng/ml, respectively. The concentration of MEHP in the serum was at or less than the LOQ. The concentration of DEHP in the serum was less than the LOQ. Contaminations of MEHP and DEHP from experimental reagents, apparatus and air during the procedure were less than the LOQ and were estimated to be <1.0 and 2.2 ± 0.6 ng/ml, respectively. After subtraction of the contamination, the net concentrations of MEHP and DEHP in the serum were estimated at or <5 and <2 ng/ml, respectively. To decrease contamination by DEHP, the cleanup steps and the apparatus and solvent usage were minimized in the sample preparation procedures. The high selectivity of LC/MS/MS is the key for obtaining reliable experimental data from in the matrix-rich analytical samples and for maintaining a low level contamination of MEHP and DEHP in this experimental system. This method would be a useful tool for the detection of MEHP and DEHP in serum.
Journal of Analytical Toxicology, 2021
Bisphenol S (BPS) has been detected in personal care products, water, food and indoor house dust, demonstrating the potential for human exposure. Due to limited data to characterize the hazard of BPS, the National Toxicology Program (NTP) is investigating the toxicity of BPS in rodent models. Generating systemic exposure data is integral to putting toxicological findings into context. The objective of this work was to develop and validate a method to quantitate free (unconjugated parent) and total (free and all conjugated forms of) BPS in rodent plasma, amniotic fluid and fetal homogenate in support of NTP studies. The method used incubation with (total BPS) and without (free BPS) deconjugating enzyme and then protein precipitation followed by ultra-performance liquid chromatography-tandem mass spectrometry. In Sprague Dawley rat plasma, the method was linear (r ≥ 0.99) over the range 5–1,000 ng/mL, accurate (mean relative error (RE) ≤ ±10.5%) and precise (relative standard deviatio...
Metabolite Profiles of Di-n-butyl Phthalate in Humans and Rats
Environmental Science & Technology, 2007
Din -butyl phthalate (DBP) is widely used in consumer products. In humans and in rats, DBP is metabolized to monon-butyl phthalate (MBP). MBP may also further oxidize to other metabolites of DBP. We studied the metabolic profiles of DBP in rats and humans to evaluate the similarities between the two species and between different exposure scenarios. In rats administered DBP by oral gavage, we identified MBP and three urinary oxidative metabolites of DBP: mono-3-oxo-n-butyl phthalate, mono-3-hydroxyn-butyl phthalate (MHBP), and mono-3-carboxypropyl phthalate (MCPP). MBP, MHBP, and MCPP were also present in serum, albeit at lower levels than in urine. Statistically significant correlations (p < 0.01) existed between the concentrations of MBP and the concentrations of MHBP (Pearson correlation coefficient r) 0.82 [urine] and r) 0.96 [serum]) and MCPP (r) 0.77 [urine] and r) 0.97 [serum]). However, the concentrations of these metabolites in urine collected 6 h after dosing and in serum 24 h after dosing were not correlated, suggesting continuous metabolism of DBP and/or individual differences among rats. Serum DBP metabolite concentrations increased with the dose, whereas urinary concentrations did not. We also identified MBP, MHBP, and MCPP in the urine of four men exposed to DBP by taking a prescription medication containing DBP, and MBP and MCPP in 94 adults with no documented exposure to DBP. In the human samples, we observed statistically significant correlations (p < 0.01) among the urinary concentrations of MBP and MCPP, although the correlation was stronger for the four exposed men (r) 0.99) than for the adults without a documented exposure to DBP (r) 0.70). Our results suggest that regardless of species and exposure scenario, MBP, the major DBP metabolite, is an optimal biomarker of exposure to DBP. In addition to MBP, MCPP and MHBP may be adequate biomarkers of exposure to DBP in occupational settings or in potential high-exposure scenarios.
Journal of Separation Science, 2011
Bisphenol A (BPA) is one of the environmental endocrine-disrupting chemicals used widely in common consumer products. There is an increasing concern about human exposure to BPA, particularly in fetuses, due to the potential adverse effects related to the estrogenic activity of BPA. In assessing environmental exposure to BPA, it is essential to have a sensitive, accurate and specific analytical method, particularly for low BPA levels in complex sample matrices. In this study, we developed and validated an accurate, sensitive, and robust liquid chromatography-mass spectrometry (LC-MS) method for determining BPA concentrations in human amniotic fluid. In this method, BPA and the internal standards 13 C 12-BPA were extracted from 500 μL of human amniotic fluid using solid phase extraction. Calibration curves were linear over a concentration range of 0.3 to 100 ng/mL for BPA. The analytes were quantitatively determined using LC-MS operated in negative electrospray ionization selected ion monitoring mode. This validated method has been used successfully in clinical sample analysis of BPA in second-trimester amniotic fluid specimens.
Teratogenic evaluation of di-n-butyl phthalate in rats
Toxicology Letters, 1993
Pregnant rats were given di-n-butyl phthalate (DBP) by gastric intubation at a dose of 0, 0.5, 0.63,0.75 or 1.0 g/kg on days 7-15 of pregnancy. A significant decrease in the maternal body weight gain after treatment with DBP was found at a dose of 0.63 g/kg and above. Maternal death and complete resorption of implanted embryos in all the surviving dams were observed in the 1.0 g/kg group. Significantly increased incidence of postimplantation loss and decreased fetal weight were detected at doses of 0.63 and 0.75 g/kg. The incidence of fetuses with malformations was higher in the 0.63 and 0.75 g/kg groups than in the control group, and the difference was significant in the 0.75 g/kg group. Cleft palate were predominantly observed.
Environmental Health Perspectives, 2003
Di-(2-ethylhexyl) phthalate (DEHP), one of the most widely used phthalates, is a primary component in polyvinyl chloride plastics used in numerous household products, toys, floor tiles, furniture upholstery, blood storage bags, and medical devices, among other products [Agency for Toxic Substances and Disease Registry (ATSDR) 2002; Faouzi et al. 1999]. Therefore, the potential for human exposure to DEHP is high. DEHP is not chemically bound in the plastics; hence, it can be leached to the environment during the manufacturing process and product use and after disposal (ATSDR 2002; Sharman et al. 1994). The general population is exposed to DEHP in food, water, and air through inhalation and ingestion (ATSDR 2002; Meek and Chan 1994; Sharman et al. 1994). Medical patients receiving transfusions (Peck et al. 1979) or dialysis (Faouzi et al. 1999) or those undergoing apheresis may be more exposed to DEHP than the general population (Ono et al. 1975). DEHP is not classifiable as to its carcinogenicity to humans by the International Agency for Research on Cancer (IARC 2000), but it has been designated a carcinogen in experimental animals (IARC 2000; Kluwe et al. 1982). Moreover, results from animal toxicologic studies have demonstrated
Pharmacokinetics of Dibutyl Phthalate (DBP) in the Rat Determined by UPLC-MS/MS
International Journal of Molecular Sciences, 2013
Dibutyl phthalate (DBP) is commonly used to increase the flexibility of plastics in industrial products. However, several plasticizers have been illegally used as clouding agents to increase dispersion of aqueous matrix in beverages. This study thus develops a rapid and validated analytical method by ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) for the evaluation of pharmacokinetics of DBP in free moving rats. The UPLC-MS/MS system equipped with positive electrospray ionization (ESI) source in multiple reaction monitoring (MRM) mode was used to monitor m/z 279.25→148.93 transitions for DBP. The limit of quantification for DBP in rat plasma and feces was 0.05 µg/mL and 0.125 µg/g, respectively. The pharmacokinetic results demonstrate that DBP appeared to have a two-compartment model in the rats; the area under concentration versus time (AUC) was 57.8 ± 5.93 min μg/mL and the distribution and elimination half-life (t 1/2,α and t 1/2,β ) were 5.77 ± 1.14 and 217 ± 131 min, respectively, after DBP administration (30 mg/kg, i.v.). About 0.18% of the administered dose was recovered from the feces within 48 h. The pharmacokinetic behavior demonstrated that DBP was quickly degraded within 2 h, suggesting a rapid metabolism low fecal cumulative excretion in the rat.