Search Results (13)

Background/Objectives: The novel compound 221s (2,9), derived from danshensu and ACEI-active proline, exhibits antihypertensive effects (50/35 mmHg SBP/DBP reduction in SHRs) with potential cough mitigation. However, its excretion kinetics remain unstudied. This study investigates 221s (2,9) elimination in rats to bridge this knowledge gap. Methods: Excretion of unchanged 221s (2,9) was quantified in urine, feces, and bile of Sprague-Dawley rats after oral administration (30 mg/kg). Concentrations of unchanged 221s (2,9) in all matrices were quantified using developed UPLC-MS/MS that underwent methodological validation. Excretion amount, excretion velocity, and accumulative excretion rate of 221s (2,9) were calculated. Results: Urinary excretion exhibited rapid elimination kinetics, reaching peak cumulative excretion rates (138.81 ± 15.56 ng/h) at 8 h post-dosing and plateauing by 48 h (cumulative excretion: 1479.81 ± 155.7 ng). Fecal excretion displayed an accelerated elimination phase between 4 and 8 h (excretion rate: 7994.29 ± 953.75 ng/h), followed by a sustained slow-release phase, culminating in a cumulative output of 36,726.31 ± 5507 ng at 48 h. Biliary excretion was minimal and ceased entirely by 24 h. Notably, total recovery of unchanged drug across all matrices remained below 1% (urine: 0.020 ± 0.021%; feces: 0.73 ± 0.069%; bile: 0.00044 ± 0.00002%) at 72 h. Conclusions: This study provides the first definitive excretion data for 221s (2,9). Quantitative analysis via a validated UPLC-MS/MS method revealed that fecal excretion is the principal elimination pathway for unchanged 221s (2,9) in rats, with direct excretion of the parent compound accounting for <1% of the administered dose over 72 h. Future studies will employ extended pharmacokinetic monitoring and concurrent UPLC-MS/MS analysis of the parent drug and phase II conjugates to resolve the observed mass imbalance and elucidate contributions to total elimination. Full article

Temephos is an organophosphorus pesticide widely used as a larvicide in public health campaigns to control vector-borne diseases. Data on the urinary elimination of temephos metabolites are limited, and there is no validated biomarker of exposure for its evaluation. This study aimed to determine the urinary excretion kinetics of temephos and its metabolites in adult male rats. Hence, adult male Wistar rats were administered orally with a single dose of temephos (300 mg/kg). Urine samples were collected at different time intervals after dosing and enzymatically hydrolyzed using β-glucuronidase/sulfatase from H. pomatia. The metabolites were extracted and analyzed by HPLC-DAD. The metabolites detected were 4,4′-thiodiphenol (TDP), 4,4′-sulfinyldiphenol (SIDP), 4,4′-sulfonyldiphenol (SODP), or bisphenol S (BPS), a non-identified metabolite, and only traces of the parent compound. The mean urine concentrations of metabolites were used for kinetic analysis. Urinary levels of TDP were fitted to a two-compartmental model, and its half-lives (t_1/2 Elim-U) were 27.8 and 272.1 h for the first and second phases, respectively. The t_1/2 Elim-U of BPS was 17.7 h. TDP, the main metabolite of temephos, was eliminated by urine and is specific and stable. Therefore, it may be used as a biomarker of temephos exposure. Full article

A food additive, silicon dioxide (SiO₂) is commonly used in the food industry as an anti-caking agent. The presence of nanoparticles (NPs) in commercial food-grade SiO₂ has raised concerns regarding their potential toxicity related to nano size. While recent studies have demonstrated the oral absorption and tissue distribution of food-additive SiO₂ particles, limited information is available about their excretion behaviors and potential impact on macrophage activation. In this study, the excretion kinetics of two differently manufactured (fumed and precipitated) SiO₂ particles were evaluated following repeated oral administration to rats for 28 d. The excretion fate of their intact particles, decomposed forms, or ionic forms was investigated in feces and urine, respectively. Monocyte uptake, Kupffer cell activation, and cytokine release were assessed after the oral administration of SiO₂ particles. Additionally, their intracellular fates were determined in Raw 264.7 cells. The results revealed that the majority of SiO₂ particles were not absorbed but directly excreted via feces in intact particle forms. Only a small portion of SiO₂ was eliminated via urine, predominantly in the form of bioconverted silicic acid and slightly decomposed ionic forms. SiO₂ particles were mainly present in particle forms inside cells, followed by ionic and silicic acid forms, indicating their slow conversion into silicic acid after cellular uptake. No effects of the manufacturing method were observed on excretion and fates. Moreover, no in vivo monocyte uptake, Kupffer cell polarization, or cytokine release were induced by orally administered SiO₂ particles. These finding contribute to understanding the oral toxicokinetics of food-additive SiO₂ and provide valuable insights into its potential toxicity. Full article

Toxicokinetic modelling provides a powerful tool in relating internal human exposure (i.e., assessed through urinary biomarker levels) to external exposure. Chemical specific toxicokinetic models are available; however, this specificity prevents their application to similar contaminants or to other routes of exposure. For this reason, we investigated whether a generic physiological-based kinetic (PBK) model might be a suitable alternative for a biokinetic model of deoxynivalenol (DON). IndusChemFate (ICF) was selected as a generic PBK model, which could be fit for purpose. Being suited for simulating multiple routes of exposure, ICF has particularly been used to relate the inhalation and dermal exposure of industrial chemicals to their urinary excretion. For the first time, the ICF model was adapted as a generic model for the human biomonitoring of mycotoxins, thereby extending its applicability domain. For this purpose, chemical-specific data for DON and its metabolites were collected directly from the literature (distribution and metabolism) or indirectly (absorption and excretion) by fitting the ICF model to previously described urinary excretion data. The obtained results indicate that this generic model can be used to model the urinary excretion of DON and its glucuronidated metabolites following dietary exposure to DON. Additionally, the present study establishes the basis for further development of the model to include an inhalation exposure route alongside the oral exposure route. Full article

Limonin is one of the research hotspots in natural drug development. However, its low solubility in water leads to poor oral bioavailability, discouraging the further study of its potential as a candidate compound. In order to overcome this limitation, and to enhance its biological activities, a novel limonin derivative—HY-071085—was synthesized by structural modification, and has exhibited strong anti-inflammatory and analgesic activity. In order to achieve a thorough understanding of the biological actions of HY-071085 in vivo, this study evaluated the pharmacokinetics and bioavailability of HY-071085 in rats and beagle dogs, and the distribution and excretion in rats. Using ultra-high-performance liquid chromatography-tandem mass spectrometry, the kinetic profiles of HY-071085 in the plasma of healthy rats and beagle dogs after a single gavage, repeated gavages and the intravenous injection of HY-071085 were studied. The tissue distribution (heart, liver, spleen, lung, kidney, gastric tissue, intestine, brain, skin, testis, ovary and womb) and excretion of HY-071085 were also studied. These results showed that HY-071085 has nonlinear dynamic characteristics in rat and beagle dog plasma. It was found that the plasma concentrations of HY-071085 in female rats were significantly higher than those in male rats after a single oral administration. There were gender differences in the kinetic behavior of HY-071085 in rats; however, there was no difference identified in dogs. HY-071085 was mainly eliminated as metabolites in rats, and was distributed in most of the tissues except the brain, with the highest content being in the gastric tissue and intestinal arease, followed by the liver, spleen, fat, lung, kidney, ovary and heart. The bioavailability of HY-071085 in male and female rats was 2.8% and 10.8%, respectively, and was about 13.1% in beagle dogs. The plasma protein binding rate of HY-071085 in rats, beagle dogs and humans ranged from 32.9% to 100%, with obvious species differences. In conclusion, our study provides useful information regarding the absorption, distribution and excretion of HY-071085, which will provide a good base for the study of the mechanism of its biological effects. Full article

Adenoviral gizzard erosion is an emerging disease with negative impact on health and production of chickens. In this study, we compared in vitro and in vivo characteristics of a fowl adenovirus serotype 1 (FAdV-1), attenuated by 53 consecutive passages in primary chicken embryo liver (CEL) cell cultures (11/7127-AT), with the virulent strain (11/7127-VT). Whole genome analysis revealed near-complete sequence identity between the strains. However, a length polymorphism in a non-coding adenine repeat sequence (11/7127-AT: 11 instead of 9) immediately downstream of the hexon open reading frame was revealed. One-step growth kinetics showed delayed multiplication of 11/7127-AT together with significantly lower titers in cell culture (up to 4 log₁₀ difference), indicating reduced replication efficiency in vitro. In vivo pathogenicity and immunogenicity were determined in day-old specific pathogen-free layer chicks inoculated orally with the respective viruses. In contrast to birds infected with 11/7127-VT, birds infected with 11/7127-AT did not exhibit body weight loss or severe pathological lesions in the gizzard. Virus detection rates, viral load in organs and virus excretion were significantly lower in birds inoculated with 11/7127-AT. Throughout the experimental period, these birds did not develop measurable neutralizing antibodies, prevalent in birds in response to 11/7127-VT infection. Differences in pathogenicity between the virulent FAdV-1 and the attenuated strain could not be correlated to prominently discriminate genomic features. We conclude that differential in vitro growth profiles indicate that attenuation is linked to modulation of viral replication during interaction of the virus with the host cells. Thus, hosts would be unable to prevent the rapid replication of virulent FAdV leading to severe tissue damage, a phenomenon broadly applicable to further FAdV serotypes, considering the substantial intra-serotype virulence differences of FAdVs and the variation of diseases. Full article

Microplastics have caused great concern in recent years. However, few studies have compared the toxicity of different sizes of microplastics in fishes, especially commercial fishes, which are more related to human health. In the present study, we revealed the effects of varying sizes of microplastics on grass carp embryos and larvae using scanning electron microscopy (SEM) and fluorescence imaging. Embryos were exposed to 80 nm and 8 μm microplastics at concentrations of 5, 15, and 45 mg/L. Toxicity kinetics of various sizes of fluorescent microplastics were analyzed through microscopic observation in the larvae. Results found that nanoplastics could not penetrate the embryo’s chorionic membrane, instead they conglutinated or aggregated on the chorion. Our results are the first to explore the defense mechanisms of commercial fish embryos against microplastics. Larvae were prone to ingesting their own excrement, resulting in microplastic flocculants winding around their mouth. For the first time, it was found that excreted microplastics could be reconsumed by fish and reaccumulated in the oral cavity. Microplastics of a certain size (1 μm) could be accumulated in the nasal cavity. We speculate that the presence of a special groove structure in the nasal cavity of grass carp larvae may manage to seize the microplastics with a particular size. As far as we know, this is the first report of microplastics being found in the nasal passages of fish. Fluorescence images clearly recorded the toxicity kinetics of microplastics in herbivorous fish. Full article

(1) Background: Metabolism data of asarone isomers, in particular phase II, in vitro and in humans is limited so far. For the first time, phase II metabolites of asarone isomers were characterized and human kinetic as well as excretion data after oral intake of asarone-containing tea infusion was determined. (2) Methods: A high pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-qTOF-MS) approach was used to identify phase II metabolites using liver microsomes of different species and in human urine samples. For quantitation of the respective glucuronides, a beta-glucuronidase treatment was performed prior to analysis via high pressure liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). (3) Results: Ingested beta-asarone and erythro and threo-asarone diols were excreted as diols and respective diol glucuronide conjugates within 24 h. An excretion rate about 42% was estimated. O-Demethylation of beta-asarone was also indicated as a human metabolic pathway because a corresponding glucuronic acid conjugate was suggested. (4) Conclusions: Already reported O-demethylation and epoxide-derived diols formation in phase I metabolism of beta-asarone in vitro was verified in humans and glucuronidation was characterized as main conjugation reaction. The excretion rate of 42% as erythro and threo-asarone diols and respective asarone diol glucuronides suggests that epoxide formation is a key step in beta-asarone metabolism, but further, as yet unknown metabolites should also be taken into consideration. Full article

Response to and monitoring of viral outbreaks can be efficiently focused when rapid, quantitative, kinetic information provides the location and the number of infected individuals. Environmental surveillance traditionally provides information on location of populations with contagious, infected individuals since infectious poliovirus is excreted whether infections are asymptomatic or symptomatic. Here, we describe development of rapid (1 week turnaround time, TAT), quantitative RT-PCR of poliovirus RNA extracted directly from concentrated environmental surveillance samples to infer the number of infected individuals excreting poliovirus. The quantitation method was validated using data from vaccination with bivalent oral polio vaccine (bOPV). The method was then applied to infer the weekly number of excreters in a large, sustained, asymptomatic outbreak of wild type 1 poliovirus in Israel (2013) in a population where >90% of the individuals received three doses of inactivated polio vaccine (IPV). Evidence-based intervention strategies were based on the short TAT for direct quantitative detection. Furthermore, a TAT shorter than the duration of poliovirus excretion allowed resampling of infected individuals. Finally, the method documented absence of infections after successful intervention of the asymptomatic outbreak. The methodologies described here can be applied to outbreaks of other excreted viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), where there are (1) significant numbers of asymptomatic infections; (2) long incubation times during which infectious virus is excreted; and (3) limited resources, facilities, and manpower that restrict the number of individuals who can be tested and re-tested. Full article

Inhalation by vaporization is a useful application mode for medical cannabis. In this study, we present the disposition of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), their acidic precursors, and their metabolites in serum, oral fluid, and urine together with the acute pharmacological effects in 14 healthy individuals treated with vaporized medical cannabis. THC and CBD peaked firstly in serum and then in oral fluid, with higher concentrations in the first biological matrices and consequent higher area under the curve AUCs. Acidic precursors Δ-9-tetrahydrocannabinolic acid A (THCA) and cannabidiolic acid (CBDA) showed a similar time course profile but lower concentrations due to the fact that vaporization partly decarboxylated these compounds. All THC and CBD metabolites showed a later onset with respect to the parent compounds in the absorption phase and a slower decrease to baseline. In agreement with serum kinetics, THC-COOH-GLUC and 7-COOH-CBD were the significantly most excreted THC and CBD metabolites. The administration of vaporized medical cannabis induced prototypical effects associated with the administration of cannabis or THC in humans, with a kinetic trend overlapping that of parent compounds and metabolites in serum. The pharmacokinetics of cannabinoids, their precursors, and their metabolites in biological fluids of individuals treated with vaporized medical cannabis preparations showed a high interindividual variability as in the case of oral medical cannabis decoction and oil. Inhaled medical cannabis was absorbed into the organism earlier than decoction and oil. Cannabinoids reached higher systemic concentrations, also due to the fact that the acid precursors decarboxylated to parent cannabinoids at high temperatures, and consequently, the physiological and subjective effects occurred earlier and resulted with higher intensity. No serious adverse effects were observed. Full article

Biomarkers for the determination of the dietary exposure to deoxynivalenol (DON) have been proposed in the past but so far no quantification of their use in humans has been carried out. Following a human intervention study with two mycotoxins, namely DON and deoxynivalenol-3-glucoside (DON3G), the renal excretion of these compounds, including their phase II metabolites, was analysed. The purpose was to develop biokinetic models that can be used to determine: (1) the preferred (set of) urinary biomarker(s), (2) the preferred urinary collection period, and (3) a method to estimate the dietary exposure to these mycotoxins. Twenty adult volunteers were restricted in consuming cereals and cereal-based foods for 4 days. At day 3, a single dose of 1 µg/kg body weight of DON or DON3G was orally administered to 16 volunteers; 4 volunteers served as control. All individual urine discharges were collected during 24 h after administration. The metabolism and renal excretion could be described by a biokinetic model using three physiological compartments (gastrointestinal tract, liver, and kidneys). Kinetic analysis revealed a complete recovery of the renal excretion of total DON (mainly DON and its glucuronides) within 24 h after administration of DON or DON3G. The so-called ‘reverse dosimetry’ factor was used to determine the preferred (set of) biomarker(s) and to estimate the dietary intake of the parent compounds in the future. The fact that DON3G was absorbed and mainly excreted as DON and its glucuronides confirms that DON3G (as well as other modified forms) should be taken into account in the exposure and risk assessment of this group of mycotoxins. Full article

Methyl 3-amino-6-methoxythieno [2,3-b] quinoline-2-carboxylate (PU-48) is a novel diuretic urea transporter inhibitor. The aim of this study is to investigate the profile of plasma pharmacokinetics, tissue distribution, and excretion by oral dosing of PU-48 in rats. Concentrations of PU-48 within biological samples are determined using a validated high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. After oral administration of PU-48 (3, 6, and 12 mg/kg, respectively) in self-nanomicroemulsifying drug delivery system (SNEDDS) formulation, the peak plasma concentrations (C_max), and the area under the curve (AUC_0–∞) were increased by the dose-dependent and linear manner, but the marked different of plasma half-life (t_1/2) were not observed. This suggests that the pharmacokinetic profile of PU-48 prototype was first-order elimination kinetic characteristics within the oral three doses range in rat plasma. Moreover, the prototype of PU-48 was rapidly and extensively distributed into thirteen tissues, especially higher concentrations were detected in stomach, intestine, liver, kidney, and bladder. The total accumulative excretion of PU-48 in the urine, feces, and bile was less than 2%. This research is the first report on disposition via oral administration of PU-48 in rats, and it provides important information for further development of PU-48 as a diuretic drug candidate. Full article

Titanium dioxide (TiO₂) nanoparticles (NPs) have been widely applied in various industrial fields, such as electronics, packaging, food, and cosmetics. Accordingly, concerns about the potential toxicity of TiO₂ NPs have increased. In order to comprehend their in vivo behavior and potential toxicity, we must evaluate the interactions between TiO₂ NPs and biomolecules, which can alter the physicochemical properties and the fate of NPs under physiological conditions. In the present study, in vivo solubility, oral absorption, tissue distribution, and excretion kinetics of food grade TiO₂ (f-TiO₂) NPs were evaluated following a single-dose oral administration to rats and were compared to those of general grade TiO₂ (g-TiO₂) NPs. The effect of the interactions between the TiO₂ NPs and biomolecules, such as glucose and albumin, on oral absorption was also investigated, with the aim of determining the surface interactions between them. The intestinal transport pathway was also assessed using 3-dimensional culture systems. The results demonstrate that slightly higher oral absorption of f-TiO₂ NPs compared to g-TiO₂ NPs could be related to their intestinal transport mechanism by microfold (M) cells, however, most of the NPs were eliminated through the feces. Moreover, the biokinetics of f-TiO₂ NPs was highly dependent on their interaction with biomolecules, and the dispersibility was affected by modified surface chemistry. Full article