Dose prediction for repurposing nitazoxanide in SARS-CoV-2 treatment or chemoprophylaxis.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been declared a global pandemic and urgent treatment and prevention strategies are needed. Nitazoxanide, an anthelmintic drug, has been shown to exhibit in vitro activity against SARS-CoV-2. The present study used physiologically based pharmacokinetic (PBPK) modelling to inform optimal doses of nitazoxanide capable of maintaining plasma and lung tizoxanide exposures above the reported SARS-CoV-2 EC90 . METHODS: A whole-body PBPK model was validated against available pharmacokinetic data for healthy individuals receiving single and multiple doses between 500 and 4000 mg with and without food. The validated model was used to predict doses expected to maintain tizoxanide plasma and lung concentrations above the EC90 in >90% of the simulated population. PopDes was used to estimate an optimal sparse sampling strategy for future clinical trials. RESULTS: The PBPK model was successfully validated against the reported human pharmacokinetics. The model predicted optimal doses of 1200 mg QID, 1600 mg TID and 2900 mg BID in the fasted state and 700 mg QID, 900 mg TID and 1400 mg BID when given with food. For BID regimens an optimal sparse sampling strategy of 0.25, 1, 3 and 12 hours post dose was estimated. CONCLUSION: The PBPK model predicted tizoxanide concentrations within doses of nitazoxanide already given to humans previously. The reported dosing strategies provide a rational basis for design of clinical trials with nitazoxanide for the treatment or prevention of SARS-CoV-2 infection. A concordant higher dose of nitazoxanide is now planned for investigation in the seamless phase I/IIa AGILE trial.

Relationship between imidacloprid residues and control effect on cotton aphids in arid region.

In this case, the dissipation and residues of imidacloprid as well as its control efficacy against aphids (Aphis gossypii Glover) in cotton cropping system were reported. After the final spray at the rates of 10.5-42.5 g a.i. ha-1, the initial deposits were 0.59-2.25 mg kg-1 with half-lives of 2.12-2.84 days on leaves and 0.06-0.21 mg kg-1 with half-lives of 1.51-4.20 days in soil, respectively. The initial residues were significantly higher with longer persistence in the upper position of the leaf than in middle and lower positions. The different application dosages could induce a significant difference in the initial deposits, but not show consistent correlation with the dissipation rate. The repeated applications of imidacloprid could alter its residue levels and dissipation rates. The long-term residue concentrations of imidacloprid (60 days after the final application) reached to the nondetectable level in soil. Combined with the control efficacy results, it was considered that the recommended dose of imidacloprid on cotton could be used effectively and safe in this arid area from the view of crop protection and environmental contamination.

Early Bactericidal Activity Trial of Nitazoxanide for Pulmonary Tuberculosis.

This study was conducted in treatment-naive adults with drug-susceptible pulmonary tuberculosis in Port-au-Prince, Haiti, to assess the safety, bactericidal activity, and pharmacokinetics of nitazoxanide (NTZ). This was a prospective phase II clinical trial in 30 adults with pulmonary tuberculosis. Twenty participants received 1 g of NTZ orally twice daily for 14 days. A control group of 10 participants received standard therapy over 14 days. The primary outcome was the change in time to culture positivity (TTP) in an automated liquid culture system. The most common adverse events seen in the NTZ group were gastrointestinal complaints and headache. The mean change in TTP in sputum over 14 days in the NTZ group was 3.2 h ± 22.6 h and was not statistically significant (P = 0.56). The mean change in TTP in the standard therapy group was significantly increased, at 134 h ± 45.2 h (P < 0.0001). The mean NTZ MIC for Mycobacterium tuberculosis isolates was 12.3 µg/ml; the mean NTZ maximum concentration (Cmax) in plasma was 10.2 µg/ml. Negligible NTZ levels were measured in sputum. At the doses used, NTZ did not show bactericidal activity against M. tuberculosis Plasma concentrations of NTZ were below the MIC, and its negligible accumulation in pulmonary sites may explain the lack of bactericidal activity. (This study has been registered at ClinicalTrials.gov under identifier NCT02684240.).

CXA-10, a Nitrated Fatty Acid, Is Renoprotective in Deoxycorticosterone Acetate-Salt Nephropathy.

Underlying pathogenic mechanisms in chronic kidney disease (CKD) include chronic inflammation, oxidant stress, and matrix remodeling associated with dysregulated nuclear factor-κ B, nuclear factor-κ B, and SMAD signaling pathways, respectively. Important cytoprotective mechanisms activated by oxidative inflammatory conditions are mediated by nitrated fatty acids that covalently modify proteins to limit inflammation and oxidant stress. In the present study, we evaluated the effects of chronic treatment with CXA-10 (10-nitro-9(E)-octadec-9-enoic acid) in the uninephrectomized deoxycorticosterone acetate-high-salt mouse model of CKD. After 4 weeks of treatment, CXA-10 [2.5 millligrams per kilogram (mpk), p.o.] significantly attenuated increases in plasma cholesterol, heart weight, and kidney weight observed in the model without impacting systemic arterial blood pressure. CXA-10 also reduced albuminuria, nephrinuria, glomerular hypertrophy, and glomerulosclerosis in the model. Inflammatory MCP-1 and fibrosis (collagen, fibronectin, plasminogen activator inhibitor-1, and osteopontin) renal biomarkers were significantly reduced in the CXA-10 (2.5 mpk) group. The anti-inflammatory and antifibrotic effects, as well as glomerular protection, were not observed in the enalapril-treated group. Also, CXA-10 appears to exhibit hormesis as all protective effects observed in the low-dose group were absent in the high-dose group (12.5 mpk). Taken together, these findings demonstrate that, at the appropriate dose, the nitrated fatty acid CXA-10 exhibits anti-inflammatory and antifibrotic effects in the kidney and limits renal injury in a model of CKD.

Dissipation, residues, and risk assessment of imidacloprid in Zizania latifolia and purple sweet potato under field conditions using LC-MS/MS.

A shortened version of Quick, Easy, Cheap, Effective, Rugged, and Safe method (QuEChERS) for determining the dissipation and residue of imidacloprid present in Zizania latifolia and purple sweet potato was established by using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The average recoveries of imidacloprid in the two crops ranged from 82.12 to 113.79%, with relative standard deviation (RSD) of <7.32%. The dissipation dynamics of imidacloprid in Z. latifolia plants and purple sweet potato plants followed first-order kinetics, with half-lives of 3.2-5.5 days in each of sampling locations. The terminal imidacloprid residues in Z. latifolia and purple sweet potato at each of location were <0.005-0.120 mg kg-1. According to the risk assessment results, both the acute dietary risk quotient and chronic dietary risk quotient values were <1, indicating that imidacloprid is unlikely to pose health risks to humans with normal recommended use. The present study may serve as a valuable reference for the safe and reasonable use of imidacloprid in Z. latifolia and purple sweet potato fields.

3-Nitro-1,2,4-triazol-5-one (2014).

3-Nitro-1,2,4-triazol-5-one (NTO) is a potential replacement for energetics in military munitions. It is a component of IMX-101, a munition designed to prevent unintentional detonation. This report summarizes the dermal, oral, and inhalation animal toxicity data, including the results of genotoxicity and limited reproductive and developmental studies. NTO has an acute LD50 in rats and mice of >5000 mg/kg, is a potential eye and skin irritant, but does not induce skin sensitization. Acute inhalation toxicity studies in rats were negative, but testicular hypoplasia was observed in a 14-day oral study in rats administered NTO at >500 mg/kg/day. Similar findings were noted in an oral 90-day study at dosages >315 mg/kg/day and in reproductive toxicity studies at >125 mg/kg/day. NTO did not cause any developmental defects. All genotoxicity studies were negative. ADME and pharmacokinetics data showed rapid uptake and elimination of NTO from both inhalation and oral intakes. Biotransformation by liver microsomes demonstrated two separate pathways, one aerobic and the other anaerobic. NTO is not considered an endocrine disruptor. There is very little human data regarding NTO or the IMX-101 mixtures. Using testicular changes in rats as the point of departure for deriving a Workplace Environmental Exposure Level (WEEL) for NTO, the resulting BMDL10 was 40 mg/kg/day, and the 8-hour time-weighted average was 2 mg/m2.

Comparisons of pharmacokinetics and NO-releasing of nitrofibriate and fenofibrate after oral administration in rats.

Nitrofibriate, a new compound of hypolipidemic, is modified based on fenofibrate. Both of them are used for prevention and treatment of cardiovascular diseases. In this study, an accurate and sensitive analytical method of reversed-phase high-performance liquid chromatography was developed to determine fenofibric acid, which is an active metabolite of both nitrofibriate and fenofibrate in rat plasma. This method was validated and successfully applied to pharmacokinetic study of nitrofibriate and fenofibrate after oral administration. The results suggested that the pharmacokinetic behavior of nitrofibriate followed a nonlinear process, while fenofibrate was linear, demonstrating that the two drugs were different in pharmacokinetic behaviors. Moreover, the effect of fenofibrate and nitrofibriate on releasing NO in rat serum was explored. This study showed that nitrofibriate, as a nitric oxide donor, could slowly release nitric oxide in vivo. This study provided a biopharmaceutical basis for further study of nitrofibriate.

Safety and activity of RRx-001 in patients with advanced cancer: a first-in-human, open-label, dose-escalation phase 1 study.

BACKGROUND: Epigenetic alterations have been strongly associated with tumour formation and resistance to chemotherapeutic drugs, and epigenetic modifications are an attractive target in cancer research. RRx-001 is activated by hypoxia and induces the generation of reactive oxygen and nitrogen species that can epigenetically modulate DNA methylation, histone deacetylation, and lysine demethylation. The aim of this phase 1 study was to assess the safety, tolerability, and pharmacokinetics of RRx-001. METHODS: In this open-label, dose-escalation, phase 1 study, we recruited adult patients (aged >18 years) with histologically or cytologically confirmed diagnosis of advanced, malignant, incurable solid tumours from University of California at San Diego, CA, USA, and Sarah Cannon Research Institute, Nashville, TN, USA. Key eligibility criteria included evaluable disease, Eastern Cooperative Group performance status of 2 or less, an estimated life expectancy of at least 12 weeks, adequate laboratory parameters, discontinuation of all previous antineoplastic therapies at least 6 weeks before intervention, and no residual side-effects from previous therapies. Patients were assigned to receive intravenous infusions of RRx-001 at increasing doses (10 mg/m(2), 16·7 mg/m(2), 24·6 mg/m(2), 33 mg/m(2), 55 mg/m(2), and 83 mg/m(2)) either once or twice-weekly for at least 4 weeks, with at least three patients per dose cohort and allowing a 2-week observation period before dose escalation. Samples for safety and pharmacokinetics analysis, including standard chemistry and haematological panels, were taken on each treatment day. The primary objective was to assess safety, tolerability, and dose-limiting toxic effects of RRx-001, to determine single-dose pharmacokinetics, and to identify a recommended dose for phase 2 trials. All analyses were done per protocol. Accrual is complete and follow-up is still on-going. This trial is registered with ClinicalTrials.gov, number NCT01359982. FINDINGS: Between Oct 10, 2011, and March 18, 2013, we enrolled 25 patients and treated six patients in the 10 mg/m(2) cohort, three patients in the 16·7 mg/m(2) cohort, three patients in the 24·6 mg/m(2) cohort, four patients in the 33 mg/m(2) cohort, three patients in the 55 mg/m(2), and six patients in the 83 mg/m(2) cohort. Pain at the injection site, mostly grade 1 and grade 2, was the most common adverse event related to treatment, experienced by 21 (84%) patients. Other common drug-related adverse events included arm swelling or oedema (eight [32%] patients), and vein hardening (seven [28%] patients). No dose-limiting toxicities were observed. Time constraints related to management of infusion pain from RRx-001 resulted in a maximally feasible dose of 83 mg/m(2). Of the 21 evaluable patients, one (5%) patient had a partial response, 14 (67%) patients had stable disease, and six (29%) patients had progressive disease; all responses were across a variety of tumour types. Four patients who had received RRx-001 were subsequently rechallenged with a treatment that they had become refractory to; all four responded to the rechallenge. INTERPRETATION: RRx-001 is a well-tolerated novel compound without clinically significant toxic effects at the tested doses. Preliminary evidence of activity is promising and, on the basis of all findings, a dose of 16·7 mg/m(2) was recommended as the targeted dose for phase 2 trials. FUNDING: EpicentRx (formerly RadioRx).

Enantioselective degradation of chiral insecticide dinotefuran in greenhouse cucumber and soil.

The enantioselective degradation behavior of the chiral insecticide dinotefuran in cucumber and soil was investigated under greenhouse conditions based on the method established with a normal-phase high-performance chromatography (HPLC) on a ChromegaChiral CCA column (250 × 4.6 mm, 5 µm, ES Industries). The linearity range, matrix effect, precision, and accuracy of the method were evaluated and the method was then successfully applied for the enantioselective analysis of dinotefuran in cucumber and soil. Significant enantioselectivity of degradation was observed in soil according to the results. The (+)-dinotefuran was more persistent in soil with half-life of 21.7 d, which is much longer than that of (-)-dinotefuran (16.5 d). In cucumber, the (-)-dinotefuran also tended to be preferentially degraded both in foliar and douche treatment. However, the statistical analysis indicated the enantioselectivity of degradation in cucumber was not significant. The research provides the first report concerning the enantioselective degradation of dinotefuran enantiomers and the results can be used for understanding the insect-controlling effect and food safety evaluation.

Macrocyclic-, polycyclic-, and nitro musks in cosmetics, household commodities and indoor dusts collected from Japan: implications for their human exposure.

This paper reported the occurrence and concentrations of macrocyclic-, polycyclic- and nitro musks in cosmetics and household commodities collected from Japan. The high concentrations and detection frequencies of Musk T, habanolide, and exaltolides were found in commercial products, suggesting their large amounts of production and usage in Japan. Polycyclic musks, HHCB and OTNE, also showed high concentrations in cosmetics and products. The estimated dairy intakes of Musk T and HHCB by the dermal exposure to commercial products were 7.8 and 7.9 µg/kg/day in human, respectively, and perfume and body lotion are dominant exposure sources. We also analyzed synthetic musks in house dusts. Polycyclic musks, HHCB and OTNE, showed high concentrations in samples, but macrocyclic musks were detected only in a few samples, although these types of musks were highly detected in commercial products. This is probably due to easy-degradation of macrocyclic musks in indoor environment. The dairy intakes of HHCB by dust ingestions were 0.22 ng/kg/day in human, which were approximately five orders of magnitudes lower than those of dermal absorption from commercial household commodities.

Toxicokinetic Model Development for the Insensitive Munitions Component 3-Nitro-1,2,4-Triazol-5-One.

3-Nitro-1,2,4-triazol-5-one (NTO) is a component of insensitive munitions that are potential replacements for conventional explosives. Toxicokinetic data can aid in the interpretation of toxicity studies and interspecies extrapolation, but only limited data on the toxicokinetics and metabolism of NTO are available. To supplement these limited data, further in vivo studies of NTO in rats were conducted and blood concentrations were measured, tissue distribution of NTO was estimated using an in silico method, and physiologically based pharmacokinetic models of the disposition of NTO in rats and macaques were developed and extrapolated to humans. The model predictions can be used to extrapolate from designated points of departure identified from rat toxicology studies to provide a scientific basis for estimates of acceptable human exposure levels for NTO.

Oral toxicity of 3-nitro-1,2,4-triazol-5-one in rats.

3-Nitro-1,2,4-triazol-5-one (NTO), an insensitive explosive, was evaluated to assess potential environmental and human health effects. A 14-day oral toxicity study in Sprague-Dawley rats was conducted with NTO in polyethylene glycol -200 by gavage at doses of 0, 250, 500, 1000, 1500, or 2000 mg/kg-d. Body mass and food consumption decreased in males (2000 mg/kg-d), and testes mass was reduced at doses of 500 mg/kg-d and greater. Based on the findings in the 14-day study, a 90-day study was conducted at doses of 0, 30, 100, 315, or 1000 mg/kg-d NTO. There was no effect on food consumption, body mass, or neurobehavioral parameters. Males in the 315 and 1000 mg/kg-d groups had reduced testes mass with associated tubular degeneration and atrophy. The testicular effects were the most sensitive adverse effect and were used to derive a benchmark dose (BMD) of 70 mg/kg-d with a 10% effect level (BMDL10) of 40 mg/kg-d.

Pharmacokinetics of Nitazoxanide Dry Suspensions After Single Oral Doses in Healthy Subjects: Food Effects Evaluation and Bioequivalence Study.

Nitazoxanide (NTZ) is an effective antiparasitic drug with potent antiviral and antimicrobial activity. This randomized, open-label, 2-sequence, 2-period crossover trial was designed to evaluate the bioequivalence (BE) of the NTZ dry suspension in healthy subjects and investigated the effect of food intake on the pharmacokinetic (PK) properties of tizoxanide (an active metabolite of NTZ, TIZ). Sixty healthy Chinese subjects were enrolled and received a single dose of 500 mg/25 mL of preparations on days 1 and 4 under overnight fasting or fed conditions, respectively. The plasma concentration of TIZ was determined using high-performance liquid chromatography/tandem mass spectrometry. PK parameters were calculated using WinNonlin 8.2 and BE was evaluated using SAS 9.4. The 90% confidence intervals for the geometric mean ratio (test/reference) of maximum concentration (Cmax), the area under the curve from time 0 to the time of the last quantifiable concentration (AUC0-t), and the area under the curve from time 0 to extrapolation to infinity (AUC0-∞) were all within the equivalent interval of 80%-125%, compliant with BE requirements. In comparison with fasting, on taking the reference and test preparations of the NTZ dry suspension after a meal, the AUC0-t increased by 48.9% and 47.3%, respectively, the AUC0-∞ increased by 48.4% and 48.3%, respectively, and the post-meal Tmax was prolonged by 1.8-2 hours. Our results demonstrate that the test and reference preparations were bioequivalent. High-fat meals significantly improve the degree of drug absorption and delay the rate of drug absorption.

Biomarkers of oral exposure to 3-nitro-1,2,4-triazol-5-one (NTO) and 2,4-dinitroanisole (DNAN) in blood and urine of rhesus macaques (Macaca mulatta).

The U.S. Department of Defense is using the chemicals 2,4-dinitroanisole (DNAN) and 3-nitro-1, 2,4-triazol-5-one (NTO) in new munitions development. In a screen for biomarkers of exposure, these compounds were measured in urine and blood of male rhesus monkeys after oral doses. NTO peaked at 4 h, with urinary concentrations at least 100-fold higher than that of blood or serum while 4-dinitrophenol (DNP), a metabolite of DNAN, appeared in blood at concentrations 10- to 20-fold higher than the parent compound. For human exposure monitoring, urine is optimal for NTO while the metabolite DNP in blood is best for DNAN.

Persistence behavior of imidacloprid and carbosulfan in mango (Mangifera indica L.).

Imidacloprid was sprayed on mango cv. Dashehari at 0.3 mL L(-1) of water during pre-bloom stage with 6-8 cm panicle size (first week of March) to control hopper and carbosulfan was sprayed at 2.0 mL L(-1) of water in the trees of mango hybrid (H-1000) during fruit development stage (first week of May) to control leaf webber. Residues of both the insecticides were analysed in peel, pulp and fruit at different stages of fruit development and maturity. The initial residues of imidacloprid, after 30 days of spraying, were 1.21, 0.56 and 1.77 mg kg(-1) in peel, pulp and whole fruit, respectively. The residues persisted in peel for 60 days and in pulp for 50 days and dissipated with a half-life of 38 days. Mature Dashehari fruits at harvest (after 85 days of spraying) were free from imidacloprid residues. Carbosulfan in mango peel dissipated from 5.30 mg kg(-1) (after 1 h of spraying) to 0.05 mg kg(-1) at the time of harvest (after 45 days of spraying). Carbosulfan residue in pulp was very low (0.08 mg kg(-1)) after 1 h of spraying, which increased gradually to 0.90 mg kg(-1) after 10 days and finally came down to 0.04 mg kg(-1) after 26 days of spraying. The insecticide residue was not detected in the pulp at the time of harvest. The residues persisted in pulp for 26 days and in peel for 45 days and degraded with a half-life of 7 days. The dissipation of both imidacloprid and carbosulfan followed first order rate kinetics in whole fruit (peel + pulp). Therefore, the safe pre-harvest intervals were suggested to be 55 days for imidacloprid and 46 days for carbosulfan before consumption of mango fruits after spraying of these insecticides.

Preclinical evaluation of the metabolism and disposition of RRx-001, a novel investigative anticancer agent.

RRx-001 has shown promise as a novel cancer therapeutic agent. The disposition of RRx-001 was evaluated in vitro and after intravenous administration to rats. At both 24 and 168 h after a single intravenous administration of ¹4C-RRx-001 (10 mg/kg), the majority of radiolabel was in the blood. The recovery of label in excreta was quite low, but the major route of radiolabel excretion was via the kidney, with approximately 26% in the urine by the first 8 h and decreasing amounts in all subsequent collections to a total of 36.3% by 168 h. The partitioning of total radioactivity in red blood cells (RBCs) and plasma was determined after in vitro addition to human, rat, dog, and monkey whole blood at 1 and 20 µM. In rat, at 30 min, approximately 75% of the radioactivity is associated with RBCs and 25% with plasma. In human, at 30 min, approximately 25% of the radioactivity is associated with RBCs and 75% with plasma. Analysis by liquid chromatography/radiodetection/mass spectrometry showed that ¹4C-RRx-001 reacted rapidly with whole blood to give four major soluble metabolites: the GSH and Cys adducts of RRx-001 (M1 and M2) and the corresponding mononitro GSH and Cys adducts (M3 and M4). Human Hb was incubated with cold RRx-001 in buffer, and a standard proteomics protocol was used to separate and identify the tryptic peptides. Standard peptide collision-induced fragment ions supported the structure of the peptide GTFATLSELHCDK with the alkylation on the Cys-93 locus of the Hb ß chain.

Metabolism and disposition of 2-methoxy-4-nitroaniline in male and female Harlan Sprague Dawley rats and B6C3F1/N mice.

The disposition of 2-Methoxy-4-nitroaniline (MNA) was investigated in male and female Harlan Sprague Dawley rats and B6C3F(1)/N mice following oral, intravenous, and dermal exposure to [(14)C]MNA at 2, 15, or 150 mg/kg. Clearance of MNA was investigated in male and female rat, mouse, and human hepatocytes. MNA was cleared slowly in hepatocytes from rat (t(1/2) = 152-424 min) and human (t(1/2) = 118-403 min) but faster in mouse (t(1/2)= 70-106 min). MNA was well-absorbed in rats and mice following oral administration and eliminated chiefly in urine (rats, 75-79%; mice, 55-68%) 72 h post dosing. Less than 1% of the radioactivity remained in tissues at 72 h. MNA was poorly absorbed following dermal application in rats (5.5%) and mice (10%) over 24 h. The major pathway of metabolism of MNA was via hydroxylation of the phenyl ring to form 6-hydroxy MNA; major metabolites detected were sulfate and glucuronide conjugates of 6-hydroxy MNA. Following oral administration, the percent of total radioactivity bound in tissues bound was highest in liver (43%) and red blood cells (30%), whereas the radioactivity bound to DNA was highest in cecum (160 pmol/mg DNA).

[Study on dermal absorption of Imidacloprid in vitro].

OBJECTIVE: The dermal absorption of Imidacloprid was studied to understand the effects of concentrations and skin reservoir on pesticide risk assessment in in vitro absorption studies. METHODS: By using Franz diffusion cell and the transdermal barrier of viable Wistar rat abdomen skin or frozen ones, the imidacloprid content in the receptor fluid and skin was determined by LC/MS/MS method, and the absorption effects were compared between two concentrations of Imidacloprid solutions and two types of skin, respectively. RESULTS: All percentages reported are % of applied dose. In vitro studies using viable skin, the Imidacloprid content in the receptor fluid of high and low concentration was 6.8%, 6.6% respectively; and 10.7%, 1.3% in skin, thus total absorption was 17.5% and 7.9%. And in vitro studies using both viable and frozen skin under the same concentration circumstances, the Imidacloprid content in the receptor fluid of viable and frozen skin was 6.6% and 0.7% respectively, in skin was 1.3% and 10.7%, and total absorption was 7.9% and 11.4%. CONCLUSION: Comparison of these in vitro results showed that either concentrations or skin reservoir had an effect on the dermal absorption. During 6h exposure, the high concentration in viable skin had the maximum dermal absorption value, which was the worst-case exposure estimate, also the best single estimate for pesticide risk assessment.

An Open Label, Adaptive, Phase 1 Trial of High-Dose Oral Nitazoxanide in Healthy Volunteers: An Antiviral Candidate for SARS-CoV-2.

Repurposing approved drugs may rapidly establish effective interventions during a public health crisis. This has yielded immunomodulatory treatments for severe coronavirus disease 2019 (COVID-19), but repurposed antivirals have not been successful to date because of redundancy of the target in vivo or suboptimal exposures at studied doses. Nitazoxanide is a US Food and Drug Administration (FDA) approved antiparasitic medicine, that physiologically-based pharmacokinetic (PBPK) modeling has indicated may provide antiviral concentrations across the dosing interval, when repurposed at higher than approved doses. Within the AGILE trial platform (NCT04746183) an open label, adaptive, phase I trial in healthy adult participants was undertaken with high-dose nitazoxanide. Participants received 1,500 mg nitazoxanide orally twice-daily with food for 7 days. Primary outcomes were safety, tolerability, optimum dose, and schedule. Intensive pharmacokinetic (PK) sampling was undertaken day 1 and 5 with minimum concentration (Cmin ) sampling on days 3 and 7. Fourteen healthy participants were enrolled between February 18 and May 11, 2021. All 14 doses were completed by 10 of 14 participants. Nitazoxanide was safe and with no significant adverse events. Moderate gastrointestinal disturbance (loose stools or diarrhea) occurred in 8 participants (57.1%), with urine and sclera discoloration in 12 (85.7%) and 9 (64.3%) participants, respectively, without clinically significant bilirubin elevation. This was self-limiting and resolved upon drug discontinuation. PBPK predictions were confirmed on day 1 but with underprediction at day 5. Median Cmin was above the in vitro target concentration on the first dose and maintained throughout. Nitazoxanide administered at 1,500 mg b.i.d. with food was safe with acceptable tolerability a phase Ib/IIa study is now being initiated in patients with COVID-19.

Simultaneous quantification of imidacloprid and its metabolites in tissues of mice upon chronic low-dose administration of imidacloprid.

This study aimed to (i) develop a sensitive method for simultaneous detection and quantification of imidacloprid (IMI) and seven of its metabolites in tissue specimens, and to (ii) determine the biodistribution of the IMI compounds in tissues of C57BL/6J male mice; after exposure to 0.6 mg/kg bw/day of IMI (10% of no observable adverse effect level of IMI) through a powdered diet for 24 weeks. We successfully developed a method which was accurate (recoveries were ≥ 70% for most compounds), sensitive (LODs ≤ 0.47 ng/mL and LOQs ≤ 1.43 ng/mL were recorded for all detected compounds, R2 ≥ 0.99) and precise (RSDs ≤ 20%) for routine analysis of IMI and seven of its metabolites in blood and various tissue matrices. After bio-distributional analysis, IMI and five of its metabolites were detected in mice. Brain, testis, lung, kidney, inguinal white adipose tissue and gonadal white adipose tissue mainly accumulated IMI, blood and mesenteric white adipose tissue mainly accumulated IMI-olefin; liver mainly accumulated desnitro-IMI; pancreas predominately accumulated 4-hydroxy-IMI. The desnitro-dehydro-IMI and the desnitro-IMI metabolites recorded tissue-blood concentration ratios ≥ 1.0 for testis, brain, lung and kidney. The cumulative levels of the six detected IMI compounds (Σ6 IMI compounds) were found in the decreasing order: blood > testis > brain > kidney > lung > iWAT > gWAT > mWAT > liver > pancreas. Altogether, this study provided essential data needed for effective mechanistic elucidation of compound-specific adverse outcomes associated with chronic exposures to IMI in mammalian species.