Mass balance and pharmacokinetics of an oral dose of 14 C-napabucasin in healthy adult male subjects.

This phase 1, open-label study assessed14 C-napabucasin absorption, metabolism, and excretion, napabucasin pharmacokinetics, and napabucasin metabolites (primary objectives); safety/tolerability were also evaluated. Eight healthy males (18-45 years) received a single oral 240-mg napabucasin dose containing ~100 µCi14 C-napabucasin. Napabucasin was absorbed and metabolized to dihydro-napabucasin (M1; an active metabolite [12.57-fold less activity than napabucasin]), the sole major circulating metabolite (median time to peak concentration: 2.75 and 2.25 h, respectively). M1 plasma concentration versus time profiles generally mirrored napabucasin; similar arithmetic mean half-lives (7.14 and 7.92 h, respectively) suggest M1 formation was rate limiting. Napabucasin systemic exposure (per Cmax and AUC) was higher than M1. The total radioactivity (TRA) whole blood:plasma ratio (AUClast : 0.376; Cmax : 0.525) indicated circulating drug-related compounds were essentially confined to plasma. Mean TRA recovery was 81.1% (feces, 57.2%; urine, 23.8%; expired air, negligible). Unlabeled napabucasin and M1 recovered in urine accounted for 13.9% and 11.0% of the dose (sum similar to urine TRA recovered); apparent renal clearance was 8.24 and 7.98 L/h. No uniquely human or disproportionate metabolite was quantified. Secondary glucuronide and sulfate conjugates were common urinary metabolites, suggesting napabucasin was mainly cleared by reductive metabolism. All subjects experienced mild treatment-emergent adverse events (TEAEs), the majority related to napabucasin. The most commonly reported TEAEs were gastrointestinal disorders. There were no clinically significant laboratory, vital sign, electrocardiogram, or physical examination changes. Napabucasin was absorbed, metabolized to M1 as the sole major circulating metabolite, and primarily excreted via feces. A single oral 240-mg dose was generally well tolerated.

Simultaneous characterization of multiple Psoraleae Fructus bioactive compounds in rat plasma by ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry for application in sex-related differences in pharmacokinetics.

A method for the simultaneous quantification of 13 bioactive compounds (psoralen, isopsoralen, isobavachin, bakuchalcone, neobabaisoflavone, bavachin, corylin, psoralidin, isobavachalcone, bavachinin, corylifol A, bavachalcone, and bakuchiol) by ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry has been developed and validated in rat plasma. Osthol was used as an internal standard and plasma samples were pretreated with one-step liquid-liquid extraction. These analytes were separated using a gradient mobile phase system of water and acetonitrile at a flow rate of 0.2 mL/min on a reverse-phase C18 column and analyzed in the selected multiple reactions monitoring mode. All calibration curves were linear (r > 0.9952) over the tested ranges. The intra- and interday accuracy and precisions of these analytes at three different concentration levels were within the acceptable limits of <15% at all concentrations. The mean recoveries of these analytes at three concentrations were more than 60.2% and the matrix effects were in the range of 85-115%. Stability studies proved that the analytes were stable under the tested conditions. The developed method was applied to evaluating the pharmacokinetic study of 13 bioactive compounds after oral administration of Psoraleae Fructus in rat of different genders. Some active compounds in Psoraleae Fructus had sex-related pharmacokinetics.

Genotoxicity and carcinogenicity risk assessment of prucalopride, a selective 5-hydroxytryptamine 4 receptor agonist.

Prucalopride, a high affinity, selective serotonin type 4 (5-HT4) receptor agonist, was associated with increased neoplasia incidence (in endocrine tissues and liver) in 2-year rodent bioassays, without evidence of a genotoxic mechanism of action. Proposed mechanisms of action involve prolactin and the constitutive androstane receptor (CAR). Epigenetic mechanisms and their relevance to humans are discussed. Data from in vitro and in vivo rodent studies demonstrated that prucalopride-related stimulation of prolactin secretion (via dopamine receptor D2 antagonism at high doses) is a rodent-specific, non-genotoxic mechanism for inducing hyperplasia and neoplasia in prolactin receptor-expressing endocrine tissues. Additional data demonstrated that CAR-mediated liver enzyme induction underlies the observed hepatocellular adenomas and thyroid follicular adenomas in rodents. A 12-month neonatal mouse carcinogenicity study confirmed the lack of a genotoxic mechanism of action. Furthermore, tumors were observed only at very high exposures (200 and 63 fold higher in mice and rats, respectively, than human exposure after a daily therapeutic dose of 2 mg). The studies indicate that non-genotoxic, rodent-specific, epigenetic mechanisms that are considered clinically irrelevant are responsible for the increased incidence of neoplasias associated with very high exposure to prucalopride in rodents, and that prucalopride does not pose a carcinogenic safety risk to humans.

The pharmacogenetics of OATP1B1 variants and their impact on the pharmacokinetics and efficacy of elbasvir/grazoprevir.

Aim: To evaluate the effect of SLCO1B1 genetic variants on grazoprevir pharmacokinetics and efficacy. Methods: A retrospective analysis of 1578 hepatitis C virus-infected participants from ten Phase II/III clinical trials. Results: Relative to noncarriers of the risk allele, geometric mean ratios (95% CI) of grazoprevir area under curve (AUC)0-24 were: rs4149056 (risk allele C), one copy, 1.13 (1.06-1.21), two copies, 1.43 (1.16-1.77); and rs11045819 (risk allele A), one copy, 0.93 (0.87-1.00); two copies, 0.78 (0.61-1.00). The rs2306283 variant was not associated with grazoprevir exposure. None of the SLCO1B1 variants were associated with sustained virologic response. Conclusion: Genetic variants in SLCO1B1 were associated with modest changes in grazoprevir pharmacokinetics, but not with meaningful differences in efficacy.

Pharmacokinetics of salvianolic acid B, rosmarinic acid and Danshensu in rat after pulmonary administration of Salvia miltiorrhiza polyphenolic acid solution.

A sensitive and accurate LC-MS/MS method was established for quantifying salvianolic acid B (Sal B), rosmarinic acid (Ros A) and Danshensu (DA) in rat plasma. Salvia miltiorrhiza polyphenolic acid (SMPA), active water-soluble ingredients isolated and purified from Salvia miltiorrhiza Bge included Sal B, Ros A and DA. The pharmacokinetic analysis of Sal B, Ros A and DA after pulmonary administration of SMPA solution to rat was performed by LC-MS/MS. Results from the pharmacokinetic studies showed that the peak concentration of DA was 21.85 ± 6.43 and 65.39 ± 3.83 ng/mL after pulmonary and intravenous administration, respectively. DA was not detected at 2 h after administration. The absolute bioavailabilities of Sal B and Ros A were respectively 50.37 ± 27.04 and 89.63 ± 12.16% after pulmonary administration of 10 mg/kg SMPA solution in rats. The absolute bioavailability of Sal B increased at least 10-fold after pulmonary administration, compared with oral administration. It was concluded that the newly established LC-MS/MS method was suitable for describing the pharmacokinetic characteristics of Sal B, Ros A and DA in rat after pulmonary administration of SMPA solution. The data from this study will provide a preclinical insight into the feasibility of pulmonary administration of SMPA.

Evaluation of the Pharmacokinetics and Safety of a Single Oral Dose of Fasiglifam in Subjects with Mild or Moderate Hepatic Impairment.

BACKGROUND AND AIMS: Fasiglifam, a potent, selective novel agonist of G protein-coupled receptor 40, stimulates insulin secretion at elevated blood glucose levels in a glucose-dependent manner. This study evaluated the potential effect of hepatic impairment on the pharmacokinetics and safety of a single dose of fasiglifam and its metabolite M-I. Fasiglifam's clinical development was halted due to liver safety concerns. METHODS: In this phase I, open-label study, subjects with mild or moderate hepatic impairment, along with matched controls (gender, weight, age, and smoking status), received a single, 25-mg oral dose of fasiglifam. Blood samples were collected through 336 h post-dose for pharmacokinetic evaluation. RESULTS: Overall, 73% of subjects were male with a mean age of 54 years. Compared with normal hepatic function subjects (n = 14), mean systemic fasiglifam exposure (Cmax and AUC∞) was reduced in mild (n = 8) and moderate (n = 8) hepatic impairment subjects by approximately 20-40%. However, the observed percent unbound drug plasma concentration appeared comparable across all groups. Mean oral clearance was higher and terminal half-life lower in subjects with mild or moderate hepatic impairment compared with normal hepatic function subjects. Fasiglifam M-I systemic exposure increased by approximately twofold in subjects with mild or moderate hepatic impairment compared with those with normal hepatic function. Fasiglifam was well tolerated, and there were no reports of hypoglycemia. CONCLUSION: Hepatic status did not significantly impact systemic exposure of fasiglifam in this study, in fact, a decrease was observed, suggesting no dose reduction would be required for patients with hepatic impairment.

The Oral Bioavailability of Trans-Resveratrol from a Grapevine-Shoot Extract in Healthy Humans is Significantly Increased by Micellar Solubilization.

SCOPE: Grapevine-shoot extract Vineatrol30 contains abundant resveratrol monomers and oligomers with health-promoting potential. However, the oral bioavailability of these compounds in humans is low (˂1-2%). The aim of this study was to improve the oral bioavailability of resveratrol from vineatrol by micellar solubilization. METHODS AND RESULTS: Twelve healthy volunteers (six women, six men) randomly ingested a single dose of 500 mg vineatrol (30 mg trans-resveratrol, 75 mg trans-ε-viniferin) as native powder or liquid micelles. Plasma and urine were collected at baseline and over 24 h after intake. Resveratrol and viniferin were analyzed by HPLC. The area under the plasma concentration-time curve (AUC) and mean maximum plasma trans-resveratrol concentrations were 5.0-fold and 10.6-fold higher, respectively, after micellar supplementation relative to the native powder. However, no detectable amounts of trans-ε-viniferin were found in either plasma or urine. The transepithelial permeability of trans-resveratrol and trans-ε-viniferin across differentiated Caco-2 monolayers was consistent to the absorbed fractions in vivo. CONCLUSION: The oral bioavailability of trans-resveratrol from the grapevine-shoot extract Vineatrol30 was significantly increased using a liquid micellar formulation, without any treatment-related adverse effects, making it a suitable system for improved supplementation of trans-resveratrol.

Inhibiting Histone Deacetylase as a Means to Reverse Resistance to Angiogenesis Inhibitors: Phase I Study of Abexinostat Plus Pazopanib in Advanced Solid Tumor Malignancies.

Purpose This phase I trial evaluated epigenetic modulation of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor by using a histone deacetylase abexinostat in combination with pazopanib to enhance response and reverse resistance. Patients and Methods Pazopanib was administered once a day on days 1 to 28 and abexinostat was administered orally twice a day on days 1 to 5, 8 to 12, and 15 to 19 (schedule A) or on days 1 to 4, 8 to 11, and 15 to 18 (schedule B). Dose escalation (3 + 3 design) in all solid tumors was followed by dose expansion in renal cell carcinoma (RCC). Results Fifty-one patients with RCC (N = 22) were enrolled, including 30 (59%) with one or more lines of prior VEGF-targeting therapy. Five dose-limiting toxicities, including fatigue (n = 2), thrombocytopenia (n = 2), and elevated AST/ALT (n = 1), were observed with schedule A; one dose-limiting toxicity was observed (elevated AST/ALT) was observed with schedule B. Grade ≥ 3 related adverse events included fatigue (16%), thrombocytopenia (16%), and neutropenia (10%). The recommended phase II dose was established as abexinostat 45 mg/m2 twice a day administered per schedule B plus pazopanib 800 mg/d. Objective response rate was 21% overall and 27% in the RCC subset. Median duration of response was 9.1 months (1.2 to > 49 months). Eight patients (16%) had durable control of disease for > 12 months. Durable tumor regressions were observed in seven (70%) of 10 patients with pazopanib-refractory disease, including one patients with RCC with ongoing response > 3.5 years. Peripheral blood histone acetylation and HDAC2 gene expression were associated with durable response to treatment. Conclusion Abexinostat is well tolerated in combination with pazopanib, allowing prolonged exposure and promising durable responses in pazopanib- and other VEGF inhibitor-refractory tumors, which supports epigenetically mediated reversal of treatment resistance.

Occupational exposure to PCDDs, PCDFs, and DL-PCBs in metallurgical plants of the Brescia (Lombardy Region, northern Italy) area.

The concentration values of polychlorodibenzodioxins (PCDDs), polychlorodibenzofurans (PCDFs), and dioxin-like polychlorobiphenyls (DL-PCBs) in blood serum samples (pools) of metallurgical workers in the area of the city of Brescia (northern Italy) were statistically processed. As to workers' exposure characteristics, pools were divided into 34 professionally exposed (PE) and 11 non-professionally exposed (NPE). A further subdivision of PE pools was according to workplaces in which ferrous (N = 24) and non-ferrous (N = 10) materials were handled. To evaluate the aforesaid differences we applied the age-adjusted Generalized Linear Models. We identified significant (P ≤ 0.05) exposure models of the classification groups. The first subdivision was confirmed by the concentrations of 1,2,3,4,6,7,8-H7CDF, DL-PCB 105, and DL-PCB 189; the second was confirmed by the concentrations of PCDF TEQ97, PCDD + PCDF + DL-PCB (TEQTOT) TEQ97, 2,3,4,7,8-P5CDF, 1,2,3,6,7,8-H6CDD, 1,2,3,4,6,7,8-H7CDD, and PCB 189. Based on the literature, all mentioned congeners have been found in stack gas and fly ash samples of metallurgical plants: therefore, these indicators indicate the exposure to such work environments. Specifically, the concentrations measured in the workers' blood serum appear to depend on the type of material processed during work.

Pharmacokinetics, absorption, and excretion of radiolabeled revexepride: a Phase I clinical trial using a microtracer and accelerator mass spectrometry-based approach.

PURPOSE: Gastroesophageal reflux disease involves the reflux of gastric and/or duodenal content into the esophagus. Prokinetic therapies, such as the selective 5-hydroxytryptamine receptor 4 agonist revexepride, may aid gastric emptying. This Phase I study evaluated the pharmacokinetics and excretion pathways of [14C]revexepride in healthy individuals using a microtracer approach with accelerator mass spectrometry. PARTICIPANTS AND METHODS: Six healthy men received a single oral dose of 2 mg [14C]revexepride containing ~200 nCi of radioactivity; blood, urine, and fecal samples were collected over a 10-day period. RESULTS: Almost 100% of 14C was recovered: 38.2%±10.3% (mean ± standard deviation) was recovered in urine, and 57.3%±0.4% was recovered in feces. Blood cell uptake was low, based on the blood plasma total radioactivity ratio of 0.8. The mean revexepride renal clearance was 8.6 L/h, which was slightly higher than the typical glomerular filtration rate in healthy individuals. Time to reach maximal concentration was 1.75±1.17 hours (mean ± standard deviation). No safety signals were identified. CONCLUSION: This study demonstrated that revexepride had rapid and moderate-to-good oral absorption. Excretion of radioactivity was completed with significant amounts in feces and urine. Renal clearance slightly exceeded the typical glomerular filtration rate, suggesting the involvement of active transportation in the renal tubules.

Comparison of the in vitro metabolism of psoralidin among different species and characterization of its inhibitory effect against UDP- glucuronosyltransferase (UGT) or cytochrome p450 (CYP450) enzymes.

Psoralidin has shown a variety of biological and pharmacological activities such as anti-tumor anti-oxidant, anti-bacterial, anti-depressant and anti-inflammatory activities. Herein, we reported the metabolism of psoralidin among different species and its inhibitory effect against UGTs and CYP450s. Liquid chromatography was used to investigate the inhibitory activity of psoralidin against ten different UGTs and eight distinct CYP450 isoforms. In addition, we characterized the CYP450 isoforms involved in the psoralidin metabolism on the basis of chemical inhibition studies and screening assays with recombinant human cytochrome P450s. In vitro metabolic profiles and metabolites of psoralidin from varying liver microsomes obtained from human (HLMs), monkey (MLMs), rat (RLMs), dog (DLMs), minipig (PLMs) and rabbit (RAMs) were determined by LC-MS/MS. In vivo pharmacokinetic profiles were investigated by injecting psoralidin (2mg/kg) into the tail vein of Wistar rats. Molecular modeling studies were carried out in order to assess the binding profile and recognition motif between psoralidin and the enzymes. Psoralidin showed potent and noncompetitive inhibition against UGT1A1, UGT1A7, CYP1A2 and CYP2C8 with IC50 values of 6.12, 0.38, 1.81, 0.28µM, respectively. The metabolism of psoraldin exhibited significant differences among humans, monkeys, dogs, minipigs, rabbits and rats; however, monkeys showed the highest similarity to humans. Furthermore, eleven metabolites were observed among these species and their structures were characterized by LC-MS/MS. CYP2C19 played a key role in the metabolism of psorslidin in human liver microsomes. These findings could be used to advance the understanding of psoralidin.

Development and validation of a UFLC-MS/MS method for determination of 7'(Z)-(8″S, 8‴S)-epi-salvianolic acid E, (7'R, 8'R, 8″S, 8‴S)-epi-salvianolic acid B and salvianolic acid B in rat plasma and its application to pharmacokinetic studies.

7'(Z)-(8″S, 8‴S)-epi-Salvianolic acid E (compound 1) and (7'R, 8'R, 8″S, 8‴S)-epi-salvianolic acid B (compound 2), two novel analogs of salvianolic acid B (Sal B), have been recently isolated from Salvianolic acid for injection. They both show powerful antioxidant effects, including inducing NQO1 activity and scavenging DPPH free radical, and potential protecting effects for cerebral ischemia. However, no reports have been described the pharmacokinetic study of them. In this study, an ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was developed and validated for the determination of compound 1, compound 2 and Sal B in rat plasma, respectively. Plasma samples were pretreated by liquid-liquid extraction with ethyl acetate. Chromatographic separation was achieved on a Waters Acquity UPLC(®) HSS T3 column (1.7µm particles, 2.1mm i.d.×100mm) with the mobile phase of 0.1% aqueous formic acid (A)-acetonitrile (B) (65:35, v/v). Quantification was performed on a triple quadruple tandem mass spectrometry with electrospray ionization (ESI) by multiple reaction monitoring (MRM) in the negative ion mode. Monitored transitions were set at m/z 717.0→519.0, 717.1→519.1, 717.2→518.9 and 320.9→152.1 for compound 1, compound 2, Sal B and chloramphenicol (internal standard, IS), respectively. Linear calibration curves were acquired over the concentration range of 2.0-1000ng/mL for the three analytes in rat plasma. The extraction recoveries, matrix effects, intra- and inter-day precisions and accuracies of the three analytes were all within acceptable limits. The validated method was successfully applied to the pharmacokinetic study of compound 1, compound 2 and Sal B after intravenous administration of 6.0mg/kg in rats, respectively. The results indicated that compound 1 and compound 2 were both eliminated more slowly than Sal B. Exposure levels of both compound 1 and Sal B were higher than compound 2 in the same dosage range. This study provided critical reference for the pharmacokinetic study of compound 1 and compound 2.

Simultaneous determination of tanshinones and polyphenolics in rat plasma by UPLC-MS/MS and its application to the pharmacokinetic interaction between them.

The aim of this study was to investigate the pharmacokinetic interaction between tanshinones and polyphenolics which act as the main bioactive compounds in Saliva miltiorrhiza Bunge (SMB). Thus, a rapid and highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to determine the concentrations of Tanshinone IIA (TSIIA), Tanshinone I (TI), Cryptotanshinone (CT), Salvianolic acid B (Sal B), Protocatechuic aldehyde (PAL), Rosmarinic acid (RA), and Danshensu (DSS) in rat plasma. The Sprague-Dawley rats were allocated to three groups which orally administered tanshinones (DST), polyphenolics (DFS), and a mixture of tanshinones and polyphenolics (DTF). These samples were processed by a simple liquid-liquid extraction (LLE) method with ethyl acetate. Chromatographic separation was achieved on an Acquity BEH C18 column (100 mm × 2. 1 mm, 1.7 µm) with the mobile phase consisting of 0.1% (v/v) formic acid and acetonitrile by gradient elution at a flow rate of 0.4 mL/min. The detection was performed on a triple quadrupole-tandem mass spectrometer TQ-MS/MS equipped with negative and positive electrospray ionization (ESI) interface in multiple reaction monitoring (MRM) mode. The statistical analysis was performed by the Student's t-test with P ≤ 0.05 as the level of significance. The method showed good precision, accuracy, recovery, sensitivity, linearity, and stability. The pharmacokinetic profiles and parameters of these polyphenolics changed when co-administrated with tanshinones. The tanshinones improved the bioavailability of DSS, accelerated the eliminating rate of RA and Sal B and promoted their distribution in vivo. They also contributed to promoting the biotransformation of Sal B to DSS. The polyphenolics could affect the pharmacokinetic of tanshinones, especially CT and TSIIA. Furthermore, the biotransformation of CT to TSIIA and the bioavailability of TSIIA were both improved. This study may provide useful information to avoid unexpected increase of the plasma drug concentration in the clinical practice. Copyright © 2015 John Wiley & Sons, Ltd.

Discovery of 3-n-butyl-2,3-dihydro-1H-isoindol-1-one as a potential anti-ischemic stroke agent.

To develop novel anti-ischemic stroke agents with better therapeutic efficacy and bioavailability, we designed and synthesized a series of 3-alkyl-2,3-dihydro-1H-isoindol-1-ones compounds (3a-i) derivatives, one of which (3d) exhibited the strongest inhibitory activity for the adenosine diphosphate-induced and arachidonic acid-induced platelet aggregation. This activity is superior to that of 3-n-butylphthalide and comparable with aspirin and edaravone. Meanwhile, 3d not only exhibited a potent activity in scavenging free radicals and improving the survival of HT22 cells against the reactive oxygen species-mediated cytotoxicity in vitro but also significantly attenuated the ischemia/reperfusion-induced oxidative stress in ischemic rat brains. Results from transient middle cerebral artery occlusion and permanent middle cerebral artery occlusion model, indicated that 3d could significantly reduce infarct size, improve neurobehavioral deficits, and prominently decrease attenuation of cerebral damage. Most importantly, 3d possessed a very high absolute bioavailability and was rapidly distributed in brain tissue to keep high plasma drug concentration for the treatment of ischemic strokes. In conclusion, our findings suggest that 3-alkyl-2,3-dihydro-1H-isoindol-1-ones, a novel series of compounds, might be candidate drugs for the treatment of acute ischemic strokes, and 3d may be a promising therapeutic agent for the primary and secondary prevention of ischemic stroke.

A UPLC-MS/MS method for in vivo and in vitro pharmacokinetic studies of psoralenoside, isopsoralenoside, psoralen and isopsoralen from Psoralea corylifolia extract.

ETHNOPHARMACOLOGICAL RELEVANCE: The dried fruit of Psoralea corylifolia L. has been used to prevent and treat vitiligo, osteoporosis, arthralgia and asthma in Traditional Chinese Medicine for some 1600 years. Psoralen (P), isopsoralen (IP), psoralenoside (PO) and isopsoralenoside (IPO) are the major coumarins and coumarin-related benzofuran glycosides in Psoraleae Fructus, which have been reported to show estrogen-like activity, osteoblastic proliferation accelerating activity, antitumor effects and antibacterial activity. The first aim of this study is to develop a rapid, sensitive and selective ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) approach for simultaneous determination of PO, IPO, P and IP in rat plasma and samples collected from in vitro incubation experiments. The second aim is to investigate the pharmacokinetic properties of PO, IPO, P and IP after oral administration of Psoralea corylifolia extract (PCE) to rats. The third aim is to confirm the biotransformation of PO to P or IPO to IP under gastrointestinal conditions. MATERIALS AND METHODS: A UPLC-MS/MS method with a C18 column and a mobile phase of methanol-0.1% aqueous formic acid was validated according to the criteria in FDA guidelines about bioanalytical method, which was developed to investigate the pharmacokinetic behavior of PO, IPO, P and IP from PCE and the metabolic pathways of PO to P or IPO to IP. RESULTS: The criteria for establishment of a new UPLC-MS/MS method including selectivity, linearity, accuracy, precision, extraction recovery, matrix effect and stability were validated. This method was successfully applied to the quantitative determination of PO, IPO, P and IP in biological samples collected from both in vitro incubations and in vivo rat experiments. After oral administration of PCE to rat, pharmacokinetic parameters of these four compounds indicated that in vivo biotransformation may occur between PO and P or IPO and IP. Purified benzofuran glycosides fraction (PBGF), containing only PO and IPO, was orally administered to rats to further confirm the biotransformation of PO to P or IPO to IP under gastrointestinal conditions. An in vitro incubation study elucidated that PO and IPO were metabolized to P and IP by intestinal microflora through de-glucosylation. CONCLUSIONS: This paper developed a rapid, sensitive and selective UPLC-MS/MS method for simultaneous determination of PO, IPO, P and IP from PCE in biological samples, and investigated on their comprehensive in vivo and in vitro pharmacokinetic studies. These obtained results showed that the metabolism by intestinal bacteria plays an important role in pharmacological effects of orally administered PCE.

Serum TCDD and TEQ concentrations among Seveso women, 20 years after the explosion.

The Seveso Women's Health Study (SWHS) is a historical cohort study of the female population residing near Seveso, Italy, on 10 July 1976, when a chemical explosion resulted in the highest known residential exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Individual TCDD concentration was measured in serum collected near the time of the explosion, and in 1996, we collected adequate blood for TCDD and total dioxin toxic equivalent (TEQ) measurement. Polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls were measured in 1996 serum for a sample (n=225, 23%) of the SWHS cohort and WHO 2005 TEQs were calculated. We examined characteristics that predict 1996 TCDD concentrations and estimated TCDD elimination half-life over the 20-year period since the explosion. Median lipid-adjusted TCDD and total TEQ concentrations in 1996 serum were 7.3 and 26.2 p.p.t., respectively. Initial 1976 TCDD and age at explosion were the strongest predictors of 1996 TCDD. The TCDD elimination half-life was 7.1 years for women older than 10 years in 1976, but was shorter in those who were younger. Twenty years after the explosion, TCDD concentrations in this SWHS sample, the majority of who were children in 1976, remain elevated relative to background. These data add to the limited data available on TCDD elimination half-life in children.

Persistent organic pollutants including polychlorinated and polybrominated dibenzo-p-dioxins and dibenzofurans in firefighters from Northern California.

Polychlorinated and polybrominated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs and PBDD/Fs) were measured in serum of twelve firefighters sampled after a fire event in San Francisco, California, along with polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), p,p'-DDE, hexachlorobenzene (HCB), perfluorinated chemicals (PFCs), bisphenol-A (BPA) and tetrabromobisphenol-A (TBBPA). TEQPCDD/F concentrations were relatively low (mean 5pgg(-1) (lipid weight), lw, range 1-11pgg(-1)lw), but concentrations of 1,2,3,4,6,7,8-HpCDD, a congener indicative of exposure during firefighting, were elevated. Tentative WHO2005-TEQs calculated for PBDD/Fs in our samples (mean 104pgg(-1)lw, range 0.2-734pgg(-1)lw) suggested that PBDD/Fs may contribute substantially to dioxin-like toxicity in individual firefighters. PBDE concentrations were elevated in firefighter serum (mean 135ngg(-1)lw, range 48-442ngg(-1)lw). PBDE-209, PBDE-47 and PBDE-153 were prevalent congeners; PBDE-209 contributed >50% of the total PBDE concentration in four individuals, implying continuous occupational exposure to deca-BDE. Perfluorooctanesulfonate (PFOS) was the dominant PFC in serum (mean 12ngml(-1) (wet weight), ww, range 3ngml(-1)ww to 59ngml(-1)ww), followed by perfluorooctanoic acid (PFOA) (mean 7ngml(-1)ww, range 2ngml(-1)ww to 12ngml(-1)ww). Concentrations of perfluorononanoic acid (PFNA) (mean 2ngml(-1)ww, range 1-4ngml(-1)ww) were higher than those reported in the high-smoke exposure group of World Trade Center fire responders, suggesting that the California firefighters were exposed to PFNA in smoke during firefighting. Given their elevated rates of cancers, these results illustrate the importance of monitoring halogenated contaminants including PBDD/Fs in firefighters.

Occupational exposure to PCDDs, PCDFs, and PCBs of metallurgical workers in some industrial plants of the Brescia area, northern Italy.

BACKGROUND: The study was carried out in order to respond to public concern on the occupational exposure of metallurgical workers to highly toxic PCDDs, PCDFs, and PCBs in the area of the city of Brescia, northern Italy. OBJECTIVES: The study investigated the effects on the haematic burden of occupational exposures to the aforesaid contaminants in different work environments, attempting to establish causal relationships and providing indications for occupational health preventive measures. METHODS: Chemical concentrations were measured in blood serum of "professionally exposed" (PE) and "not professionally exposed" (NPE) subjects. NPE subjects included industrial administrative employees, Brescia inhabitants, and remote rural people. RESULTS: The central tendency indexes of contaminant cumulative concentrations were higher in PE than in NPE samples (for the mean values: PCDDs+PCDFs, 22.9 vs. 19.5 pgWHO-TEQ(1997)/g lb; DL-PCBs, 26.0 vs. 23.6 pgWHO-TEQ(1997)/g lb; PCDDs+PCDFs+DL-PCBs (TEQ(TOT)), 48.9 vs. 43.1 pgWHO-TEQ(1997)/g lb; Σ(6)[NDL-PCBs], 427 vs. 401 ng g(-1)lb); however, no statistical differences were detected at P=0.05. A significant difference for PCDDs+PCDFs and TEQ(TOT) was observed as the NPE data were progressively reduced to those of the remote rural people. The existence of a differential occupational exposure due to different environments was detected by applying the factor analysis to congener-specific data (analytical profiles). CONCLUSIONS: Findings indicate that metallurgical workers may be exposed to PCDD, PCDF, and PCB more than the general population, in particular due to non-negligible contributions to exposure from workplace ambient air. Findings also suggest that an improvement of preventive measures may be required to avoid chemical overexposure in certain metallurgical workplaces. To identify exposure groups, the DL- and NDL-PCB analytical profiles seemed to be more sensitive to environmental exposure sources/pathways than those of PCDDs and PCDFs.

Development and validation of prediction models for blood concentrations of dioxins and PCBs using dietary intakes.

BACKGROUND: Dioxins and PCBs accumulate in the food chain and might exert toxic effects in animals and humans. In large epidemiologic studies, exposure estimates of these compounds based on analyses of biological material might not be available or affordable. OBJECTIVES: To develop and then validate models for predicting concentrations of dioxins and PCBs in blood using a comprehensive food frequency questionnaire and blood concentrations. METHODS: Prediction models were built on data from one study (n=195), and validated in an independent study group (n=66). We used linear regression to develop predictive models for dioxins and PCBs, both sums of congeners and 33 single congeners (7 and 10 polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs), 12 dioxin-like polychlorinated biphenyls (PCBs: 4 non-ortho and 8 mono-ortho), sum of all the 29 dioxin-like compounds (total TEQ) and sum of 4 non dioxin-like PCBs (∑ CB-101, 138, 153, 183=PCB(4)). We used the blood concentration and dietary intake of each of the above as dependent and independent variables, while sex, parity, age, place of living, smoking status, energy intake and education were covariates. We validated the models in a new study population comparing the predicted blood concentrations with the measured blood concentrations using correlation coefficients and Weighted Kappa (К(W)) as measures of agreement, considering К(W)>0.40 as successful prediction. RESULTS: The models explained 78% (sum dioxin-like compounds), 76% (PCDDs), 76% (PCDFs), 74% (no-PCBs), 69% (mo-PCBs), 68% (PCB(4)) and 63% (CB-153) of the variance. In addition to dietary intake, age and sex were the most important covariates. The predicted blood concentrations were highly correlated with the measured values, with r=0.75 for dl-compounds 0.70 for PCB(4), (p<0.001) and 0.66 (p<0.001) for CB-153. К(W) was 0.68 for sum dl-compounds 0.65 for both PCB(4) and CB-153. Out of 33 congeners 16 (13dl-compounds and 3 ndl PCBs) had К(W)>0.40. CONCLUSIONS: The models developed had high power to predict blood levels of dioxins and PCBs and to correctly rank subjects according to high or low exposure based on dietary intake and demographic information. These models underline the value of dietary intake data for use in investigations of associations between dioxin and PCB exposure and health outcomes in large epidemiological studies with limited biomaterial for chemical analysis.

Environmental exposure to dioxin-like compounds and the mortality risk in the U.S. population.

BACKGROUND: Little is known about the mortality risk associated with chronic dioxin exposure in the general U.S. populations. OBJECTIVE: To explore the association between dioxin-like chemicals and mortality risk in a large population-based cohort study. METHODS: The analysis included 2361 subjects aged 40 years or older from the 1999-2004 National Health and Nutrition Examination Survey (NHANES). Exposure to a mixture of dioxin-like chemicals, including dibenzo-p-dioxins, dibenzofurans, and polychlorinated biphenyls was estimated using toxic equivalency values (TEQs) calculated with 2005 World Health Organization toxic equivalency factors. All-cause and cause-specific mortalities were obtained from the NHANES-linked follow-up data through December 31, 2006. Cox proportional-hazards models were applied to assess the associations of interest. RESULTS: A total of 242 deaths occurred during the follow-up period, including 75 from cardiovascular disease and 72 from cancer. There was an increased mortality risk associated with logarithmically expressed dioxin TEQs for all-cause deaths (hazard ratio=1.19, 95% confidence interval=1.02-1.39, p=0.02). Similar graded dose-response trends were found for cardiovascular and cancer mortality which did not reach statistical significance. CONCLUSIONS: In general, higher dioxin exposure is associated with an increased mortality risk among subjects aged 40 and above. The cause-specific analyses and responsible mechanisms will require further investigation.