Design, Synthesis, and Investigation of the Pharmacokinetics and Anticancer Activities of Indenoisoquinoline Derivatives That Stabilize the G-Quadruplex in the MYC Promoter and Inhibit Topoisomerase I.

G-quadruplexes are noncanonical four-stranded DNA secondary structures. MYC is a master oncogene and the G-quadruplex formed in the MYC promoter functions as a transcriptional silencer and can be stabilized by small molecules. We have previously revealed a novel mechanism of action for indenoisoquinoline anticancer drugs, dual-downregulation of MYC and inhibition of topoisomerase I. Herein, we report the design and synthesis of novel 7-aza-8,9-methylenedioxyindenoisoquinolines based on desirable substituents and π-π stacking interactions. These compounds stabilize the MYC promoter G-quadruplex, significantly lower MYC levels in cancer cells, and inhibit topoisomerase I. MYC targeting was demonstrated by differential activities in Raji vs CA-46 cells and cytotoxicity in MYC-dependent cell lines. Cytotoxicities in the NCI-60 panel of human cancer cell lines were investigated. Favorable pharmacokinetics were established, and in vivo anticancer activities were demonstrated in xenograft mouse models. Furthermore, favorable brain penetration, brain pharmacokinetics, and anticancer activity in an orthotopic glioblastoma mouse model were demonstrated.

Enhancing the therapeutic potential of isoliensinine for hypertension through PEG-PLGA nanoparticle delivery: A comprehensive in vivo and in vitro study.

BACKGROUND: Hypertension, a highly prevalent chronic disease, is known to inflict severe damage upon blood vessels. In our previous study, isoliensinine, a kind of bibenzyl isoquinoline alkaloid which isolated from a TCM named Lotus Plumule (Nelumbo nucifera Gaertn), exhibits antihypertensive and vascular smooth muscle proliferation-inhibiting effects, but its application is limited due to poor water solubility and low bioavailability. In this study, we proposed to prepare isoliensinine loaded by PEG-PLGA polymer nanoparticles to increase its efficacy METHOD: We synthesized and thoroughly characterized PEG-PLGA nanoparticles loaded with isoliensinine using a nanoprecipitation method, denoted as, PEG-PLGA@Isoliensinine. Additionally, we conducted comprehensive investigations into the stability of PEG-PLGA@Isoliensinine, in vitro drug release profiles, and in vivo pharmacokinetics. Furthermore, we assessed the antihypertensive efficacy of this nano-system through in vitro experiments on A7R5 cells and in vivo studies using AngII-induced mice. RESULT: The findings reveal that PEG-PLGA@Isoliensinine significantly improves isoliensinine absorption by A7R5 cells and enhances targeted in vivo distribution. This translates to a more effective reduction of AngII-induced hypertension and vascular smooth muscle proliferation. CONCLUSION: In this study, we successfully prepared PEG-PLGA@Isoliensinine by nano-precipitation, and we confirmed that PEG-PLGA@Isoliensinine surpasses free isoliensinine in its effectiveness for the treatment of hypertension, as demonstrated through both in vivo and in vitro experiments. SIGNIFICANCE: This study lays the foundation for isoliensinine's clinical use in hypertension treatment and vascular lesion protection, offering new insights for enhancing the bioavailability of traditional Chinese medicine components. Importantly, no toxicity was observed, affirming the successful implementation of this innovative drug delivery system in vivo and offers a promising strategy for enhancing the effectiveness of Isoliensinine and propose an innovative avenue for developing novel formulations of traditional Chinese medicine monomers.

Pharmacokinetics, Safety, and Tolerability of Tenapanor in Healthy Chinese and Caucasian Volunteers: A Randomized, Open-Label, Single-Center, Placebo-Controlled Phase 1 Study.

Background: Tenapanor is a locally acting selective sodium-hydrogen exchanger 3 inhibitor with the potential to treat sodium/phosphorus and fluid overload in various cardiac-renal diseases, which has been approved for constipation-predominant irritable bowel syndrome in the US. The pharmacokinetics (PK) of tenapanor and its metabolite tenapanor-M1 (AZ13792925), as well as the safety and tolerability of tenapanor, were investigated in healthy Chinese and Caucasian subjects. Methods: This randomized, open-label, single-center, placebo-controlled phase 1 study (https://www.chinadrugtrials.org.cn; CTR20201783) enrolled Chinese and Caucasian healthy volunteers into 4 parallel cohorts (3 cohorts for Chinese subjects, 1 cohort for Caucasian subjects). In each cohort, 15 subjects were expected to be included and received oral tenapanor (10 or 30 mg as single dose, or 50 mg as a single dose followed by a twice-daily repeated dose from Day 5 to 11, with a single dose in the morning on Day 11) or placebo in a 4 : 1 ratio. Results: 59 healthy volunteers received tenapanor 10 mg (n = 12 Chinese), 30 mg (n = 12 Chinese), or 50 mg (n = 12 (Chinese), n = 11 (Caucasian)) or placebo (n = 12, 3 per cohort). After single and twice-daily repeated doses, tenapanor plasma concentrations were all below the limit of quantitation; tenapanor-M1 appeared slowly in plasma. In single-ascending dose evaluation (10 to 50 mg) of Chinese subjects, the mean Cmax, AUC0-t, and AUC0-∞ of tenapanor-M1 increased with increasing dose level, and AUC0-t increased approximately dose proportionally. The Cmax accumulation ratio was 1.55 to 6.92 after 50 mg repeated dose in Chinese and Caucasian subjects. Exposure to tenapanor-M1 was generally similar between the Chinese and Caucasian subjects. Tenapanor was generally well-tolerated and the safety profile was similar between the Chinese and Caucasian participants receiving tenapanor 50 mg, as measured by vital signs, physical and laboratory examination, 12-lead ECG, and adverse events. No serious adverse event or adverse event leading to withdrawal occurred. Conclusion: Tenapanor was well-tolerated, with similar PK and safety profiles between Chinese and Caucasian subjects. This trial is registered with CTR20201783.

Hair and dietary supplements testing to identify contamination with roxadustat in an adverse analytical finding.

Roxadustat is an oral inhibitor of hypoxia-inducible factor (HIF) prolyl hydroxylase, which increases endogenous erythropoiesis. WADA has included roxadustat and other HIF stabilizers on its list of prohibited substances. We describe here the case of an elite athlete (female, 31 years old, 168 cm and 53 kg) with an adverse analytical finding (AAF) with concentration of roxadustat in her urine at 0.289 ng/mL in the A sample and 0.529 ng/mL in the B sample (83% higher than A). A stability study was carried out, showing total stability of roxadustat at this concentration in urine exposed to light for 50 h, so photoisomerization degradation cannot explain the difference in concentration. Her urine had been completely negative in a control test carried out three days previously, while roxadustat had been shown to be present in urine for at least 20 days after administration of pharmacologically effective doses to an athlete. Hair concentration was 0.39 and 0.35 pg/mg in the segments corresponding to the presumed period of intake, with few adjacent segments also positive (0.29-0.33 pg/mg), likely explained by cosmetic treatments. Concentrations found in a patient treated with a pharmacologically active dose (between 100 and 120 mg 3 days a week) were more than 100 times higher (between 41 and 57 pg/mg). Numerous supplements and pharmaceuticals taken by the athlete were analyzed. Only collagen powder showed the presence of roxadustat, at a very low but highly variable concentration (100 pg/g-1000 pg/g). A female volunteer (58 years old, 169 cm and 65 kg), taking this powder at the same doses as the athlete (10 g of powder 5 times for 6 days) presented 7 roxadustat-positive urine samples (although lower than those observed in the athlete) out of 34 sampled over 7 days, the difference in powder sampling location, age, weight, height, pharmacokinetic parameters variability and level of sporting activity between the athlete and the volunteer probably explaining the difference in concentrations observed. All these results could be consistent with an AAF due to contamination by dietary supplements, which are becoming increasingly common due to the current exposome of athletes in our society.

Tenapanor: A new treatment option for hyperphosphatemia in end stage kidney disease.

PURPOSE: This narrative review explores the currently published studies that have evaluated tenapanor for the treatment of hyperphosphatemia in end-stage kidney disease (ESKD) patients on hemodialysis. This medication's new phosphate lowering mechanism of action reduces intestinal phosphate absorption predominantly through reduction of passive paracellular phosphate flux by inhibition of the sodium/hydrogen exporter isoform 3 (NHE3). Tenapanor additionally prevents active transcellular phosphate absorption compensation by decreasing the expression of sodium phosphorus 2b transport protein (NaPi2b). METHODS: A comprehensive search of the literature was conducted using PubMed and ClinicalTrials.gov search engines. The search term "tenapanor hyperphosphatemia" was used for study retrieval. Results were limited to studies published in the English language and excluded review articles. Human, animal, and in vitro studies were included. No date range was specified. RESULTS: A total of 11 primary studies were identified and included in this review, the largest human study of which enrolled 236 patients. Each study is presented in table format along with measured end points. CONCLUSIONS: Tenapanor is the first drug in its class that lowers hyperphosphatemia in ESKD patients through a novel mechanism of action involving paracellular inactive transport. Although more studies are needed, early results indicate that tenapanor may have a place in managing hyperphosphatemia in ESKD patients both as monotherapy and as an adjunct to existing phosphate binder therapy.

Safety, Tolerability, and Pharmacokinetics of Mevidalen (LY3154207), a Centrally Acting Dopamine D1 Receptor-Positive Allosteric Modulator, in Patients With Parkinson Disease.

Mevidalen (LY3154207) is a positive allosteric modulator of the dopamine D1 receptor that enhances the affinity of dopamine for the D1 receptor. The safety, tolerability, motor effects, and pharmacokinetics of mevidalen were studied in patients with Parkinson disease. Mevidalen or placebo was given once daily for 14 days to 2 cohorts of patients (cohort 1, 75 mg; cohort 2, titration from 15 to 75 mg). For both cohorts, the median time to maximum concentration for mevidalen plasma concentration was about 2 hours, the apparent steady-state clearance was 20-25 L/h, and mevidalen plasma concentrations were similar between the 1st and 14th administration in cohort 1, indicating minimal accumulation upon repeated dosing. Mevidalen was well tolerated, and most treatment-emergent adverse events were mild. Blood pressure and pulse rate increased when taking mevidalen, but there was considerable overlap with patients taking placebo, and vital signs normalized with repeated dosing. In the Movement Disorder Society-United Parkinson's Disease Rating Scale, all patients taking mevidalen showed a better motor examination sub-score on day 6 compared to only some patients in the placebo group. These data support examining mevidalen for symptomatic treatment of patients with Parkinson disease and Lewy body dementia.

No Signs of Neuroinflammation in Women With Chronic Fatigue Syndrome or Q Fever Fatigue Syndrome Using the TSPO Ligand [11C]-PK11195.

BACKGROUND AND OBJECTIVES: The pathophysiology of chronic fatigue syndrome (CFS) and Q fever fatigue syndrome (QFS) remains elusive. Recent data suggest a role for neuroinflammation as defined by increased expression of translocator protein (TSPO). In the present study, we investigated whether there are signs of neuroinflammation in female patients with CFS and QFS compared with healthy women, using PET with the TSPO ligand 11C-(R)-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline-carbox-amide ([11C]-PK11195). METHODS: The study population consisted of patients with CFS (n = 9), patients with QFS (n = 10), and healthy subjects (HSs) (n = 9). All subjects were women, matched for age (±5 years) and neighborhood, aged between 18 and 59 years, who did not use any medication other than paracetamol or oral contraceptives, and were not vaccinated in the last 6 months. None of the subjects reported substance abuse in the past 3 months or reported signs of underlying psychiatric disease on the Mini-International Neuropsychiatric Interview. All subjects underwent a [11C]-PK11195 PET scan, and the [11C]-PK11195 binding potential (BPND) was calculated. RESULTS: No statistically significant differences in BPND were found for patients with CFS or patients with QFS compared with HSs. BPND of [11C]-PK11195 correlated with symptom severity scores in patients with QFS, but a negative correlation was found in patients with CFS. DISCUSSION: In contrast to what was previously reported for CFS, we found no significant difference in BPND of [11C]-PK11195 when comparing patients with CFS or QFS with healthy neighborhood controls. In this small series, we were unable to find signs of neuroinflammation in patients with CFS and QFS. TRIAL REGISTRATION INFORMATION: EudraCT number 2014-004448-37.

Clinical Pharmacokinetics and Pharmacodynamics of Roxadustat.

The pharmacokinetics of roxadustat are well characterized, with an apparent volume of distribution after oral administration of 22-57 L, apparent clearance of 1.2-2.65 L/h, and renal clearance of 0.030-0.026 L/h in healthy volunteers; the elimination half-life is 9.6-16 h. Plasma binding is 99% and the fraction eliminated by hemodialysis is 2.34%. As an interpretation of the pharmacodynamics of roxadustat, we proposed a concept with a hypothetical cascade of two subsequent effects, first on erythropoetin (EPO) and second on hemoglobin (delta Hb). The primary effect on EPO is observed within a few hours after roxadustat administration and can be modeled using the sigmoidal Hill equation. The concentration at half-maximum effect can be inferred at 10-36 µg/mL, the Hill coefficient at 3.3, and the effect bisection time at 10-17 h, corresponding to EPO half-life. The subsequent effect on hemoglobin (delta Hb) is observed after several weeks and can be interpreted as an irreversible, dose proportional, unsaturable effect, continuing in agreement with the lifespan of red blood cells of 63-112 days.

The Impact of the Combined Administration of 1MeTIQ and MK-801 on Cell Viability, Oxidative Stress Markers, and Glutamate Release in the Rat Hippocampus.

MK-801, as an N-methyl-D-aspartate (NMDA) receptor inhibitor, causes elevation in glutamate release, which may lead to an increase in excitotoxicity, oxidative stress and, consequently, cell death. 1-Methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ) shows antioxidant activity. The aim of the present study was to evaluate the effect of combined treatment with 1MeTIQ and MK-801 on cell viability, antioxidant enzyme activity, and glutamate release in the rat hippocampus. Cytotoxicity was measured using lactate dehydrogenase leakage assay (LDH) and the methyl tetrazolium (MTT) assay; antioxidant enzyme activity (glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CAT)) were measured by ELISA kits. The release of glutamate in the rat hippocampus was measured using in vivo microdialysis methodology. An in vitro study showed that MK-801 induced cell death in a concentration-dependent manner and that 1MeTIQ partially reduced this adverse effect of MK-801. An ex vivo study indicated that MK-801 produced an increase in antioxidant enzyme activity (GPx, GR, and SOD), whereas coadministration of MK-801 and 1MeTIQ restored the activity of these enzymes to the control level. An in vivo microdialysis study demonstrated that combined treatment with both drugs decreased the release of glutamate in the rat hippocampus. The above results revealed that 1MeTIQ shows limited neuroprotective activity under conditions of glutamate-induced neurotoxicity.

Development of a UPLC-MS/MS method for the determination of narciclasine and 7-deoxynarciclasine in mouse blood and its application in pharmacokinetics.

In this study, we used ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to measure the concentration of narciclasine and 7-deoxynarciclasine in mouse blood after intravenous (i.v.) and oral administration (p.o.), and we used this method to investigate their pharmacokinetics profiles in mice. Chromatographic separation of the analytes was achieved using a UPLC HSS T3 column (2.1 mm × 100 mm, 1.8 µm) with a mobile phase consisting of acetonitrile-water (0.1% formic acid) by gradient elution. Electrospray ionization (ESI positive-ion mode)-tandem mass spectrometry in multiple reaction monitoring (MRM) mode was employed for quantitative analysis of the analytes in mouse blood samples. Twelve mice were administered narciclasine and 7-deoxynarciclasine (2 mg/kg) intravenously (iv), while the other twelve mice were administered narciclasine and 7-deoxynarciclasine (10 mg/kg) orally. The mouse blood was withdrawn from the caudal vein to be processed, after which the blood was analyzed by UPLC-MS/MS, and the corresponding data were fitted using the Drug and Statistics (DAS) software. Standard curves of narciclasine and 7-deoxynarciclasine were generated over the concentration range of 5-5000 ng/mL. The intra-day accuracy of narciclasine and 7-deoxynarciclasine was 90-105%, and the corresponding inter-day accuracy was 87-108%. The intra-day precision was less than 13%, while the inter-day precision was less than 14%. Matrix effects were also observed (between 94% and 104%), and the recovery calculated was higher than 70%. The developed and validated UPLC-MS/MS method was then successfully applied in determining the mouse pharmacokinetics of narciclasine and 7-deoxynarciclasine. From this, thebioavailabilityofnarciclasine and 7-deoxynarciclasinewasdetermined to be 10.3%and35.4%, respectively.

Tetrahydrocannabinol and Its Major Metabolites Are Not (or Are Poor) Substrates or Inhibitors of Human P-Glycoprotein [ATP-Binding Cassette (ABC) B1] and Breast Cancer Resistance Protein (ABCG2).

(-)-Δ9-Tetrahydrocannabinol (THC) is the primary psychoactive constituent of cannabis. In humans, 11-hydroxy-THC (11-OH-THC) and 11-nor-9-carboxy-THC (THC-COOH) are psychoactive and nonpsychoactive circulating metabolites of THC, respectively. Whether these cannabinoids are substrates or inhibitors of human P-glycoprotein (P-gp) or breast cancer resistance protein (BCRP) is unknown. Previous animal studies suggest that THC and its metabolites could be substrates of these transporters. Therefore, we performed Transwell, cellular accumulation, and vesicular transport assays, at pharmacologically relevant concentrations of these cannabinoids, using Madin-Darby canine kidney (MDCK) II cells or plasma membrane vesicles overexpressing human P-gp or BCRP. Neither THC nor 11-OH-THC was found to be a substrate or inhibitor of P-gp or BCRP. The efflux ratio of THC-COOH in MDCKII-BCRP cells was 1.6, which was significantly decreased to 1.0 by the BCRP inhibitor Ko143. Likewise, cellular accumulation of THC-COOH was significantly increased 1.6-fold in the presence versus absence of Ko143. THC-COOH also significantly inhibited BCRP-mediated transport of Lucifer yellow, a BCRP substrate; however, THC-COOH was neither a substrate nor an inhibitor of P-gp. Collectively, these results indicate that THC and 11-OH-THC are not substrates or inhibitors (at pharmacologically relevant concentrations) of either P-gp or BCRP. THC-COOH is a weak substrate and inhibitor of BCRP, but not of P-gp. Accordingly, we predict that P-gp/BCRP will not modulate the disposition of these cannabinoids in humans. In addition, use of these cannabinoids will not result in P-gp- or BCRP-based drug interactions. SIGNIFICANCE STATEMENT: This study systematically investigated whether Δ9-tetrahydrocannabinol (THC) and its major metabolites, 11-hydroxy-THC and 11-nor-9-carboxy-THC, are substrates and/or inhibitors of human P-gp and BCRP at pharmacologically relevant concentrations. The results obtained are highly valuable for mechanistic understanding and prediction of the roles of P-gp and BCRP in determining the human pharmacokinetics, tissue distribution, and drug interactions of cannabinoids.

Longitudinal change in TSPO PET imaging in progressive multiple sclerosis.

The objective of this pilot study was to assess a 2-year change in innate immune burden in 15 progressive multiple sclerosis (MS) patients using PK11195-PET. Sixteen age-matched healthy controls (HC) were included for baseline comparison. PK11195 uptake was higher in MS patients compared to HC within normal-appearing white matter (NAWM) and multiple gray matter regions. In patients, PK11195 uptake increased in NAWM (p = 0.01), cortex (p = 0.04), thalamus (p = 0.04), and putamen (p = 0.02) at 12 months. Among patients remaining at 24 months, there was no further increase in PK11195. Our data suggest that innate immune activity may increase over time in patients with progressive MS.

A Highly Sensitive Nonextraction-Assisted HPLC Method with Fluorescence Detection for Quantification of Duvelisib in Plasma Samples and its Application to Pharmacokinetic Study in Rats.

BACKGROUND: Duvelisib (DUV) is a new oral phosphoinositide-3-kinase (PI3K)-δ and PI3K-γ inhibitor. It has been recently granted an accelerated approval for treatment of adult patients with relapsed or refractory chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL). It is also effective in therapy of T-cell lymphoma, solid tumors, and non-Hodgkin's lymphoma. In literature, there is no method valid for quantitation of DUV in human plasma for its therapeutic monitoring and pharmacokinetic studies. PURPOSE: The purpose of this study is the establishment of a highly sensitive HPLC method with fluorescence detection for quantitation of DUV in plasma for its therapeutic monitoring and pharmacokinetic studies of DUV. METHODS: The resolution of DUV and the internal standard (IS) olaparib (OLA) was achieved on Nucleosil CN column, with a mobile phase composed of acetonitrile:water (25:75, v/v) at a flow rate of 1.7 mL min-1. The fluorescence of both DUV and OLA was detected at 410 nm after excitation at 280 nm. The method was validated according to the guidelines of bioanalytical method validation. RESULTS: The method was linear in the range of 5-100 ng mL-1, and its limit of detection (LOD) and limit of quantitation (LOQ) were 2.12 ng mL-1 and 7 ng mL-1, respectively. The precisions of the method were ≤ 8.26%, and its accuracies were ≥ 95.32%. All the other validation parameters were satisfactory. The proposed method was successfully employed to the investigation of the pharmacokinetic profile of DUV in rats following a 25 mg/kg single dose of oral administration. CONCLUSION: The method is characterized with high sensitivity, accuracy, simple sample pretreatment, rapidity, eco-friendly as it consumes low volumes of organic solvent in the mobile phase and has high analysis throughput as its run time was short (~ 10 min).

Pharmacokinetic-pharmacodynamic guided optimisation of dose and schedule of CGM097, an HDM2 inhibitor, in preclinical and clinical studies.

BACKGROUND: CGM097 inhibits the p53-HDM2 interaction leading to downstream p53 activation. Preclinical in vivo studies support clinical exploration while providing preliminary evidence for dosing regimens. This first-in-human phase I study aimed at assessing the safety, MTD, PK/PD and preliminary antitumor activity of CGM097 in advanced solid tumour patients (NCT01760525). METHODS: Fifty-one patients received oral treatment with CGM097 10-400 mg 3qw (n = 31) or 300-700 mg 3qw 2 weeks on/1 week off (n = 20). Choice of dose regimen was guided by PD biomarkers, and quantitative models describing the effect of CGM097 on circulating platelet and PD kinetics. RESULTS: No dose-limiting toxicities were reported in any regimens. The most common treatment-related grade 3/4 AEs were haematologic events. PK/PD models well described the time course of platelet and serum GDF-15 changes, providing a tool to predict response to CGM097 for dose-limiting thrombocytopenia and GDF-15 biomarker. The disease control rate was 39%, including one partial response and 19 patients in stable disease. Twenty patients had a cumulative treatment duration of >16 weeks, with eight patients on treatment for >32 weeks. The MTD was not determined. CONCLUSIONS: Despite delayed-onset thrombocytopenia frequently observed, the tolerability of CGM097 appears manageable. This study provided insights on dosing optimisation for next-generation HDM2 inhibitors. TRANSLATIONAL RELEVANCE: Haematologic toxicity with delayed thrombocytopenia is a well-known on-target effect of HDM2 inhibitors. Here we have developed a PK/PD guided approach to optimise the dose and schedule of CGM097, a novel HDM2 inhibitor, using exposure, platelets and GDF-15, a known p53 downstream target to predict patients at higher risk to develop thrombocytopenia. While CGM097 had shown limited activity, with disease control rate of 39% and only one patient in partial response, the preliminary data from the first-in-human escalation study together with the PK/PD modeling provide important insights on how to optimize dosing of next generation HDM2 inhibitors to mitigate hematologic toxicity.

Diffusion MRI and anatomic tracing in the same brain reveal common failure modes of tractography.

Anatomic tracing is recognized as a critical source of knowledge on brain circuitry that can be used to assess the accuracy of diffusion MRI (dMRI) tractography. However, most prior studies that have performed such assessments have used dMRI and tracer data from different brains and/or have been limited in the scope of dMRI analysis methods allowed by the data. In this work, we perform a quantitative, voxel-wise comparison of dMRI tractography and anatomic tracing data in the same macaque brain. An ex vivo dMRI acquisition with high angular resolution and high maximum b-value allows us to compare a range of q-space sampling, orientation reconstruction, and tractography strategies. The availability of tracing in the same brain allows us to localize the sources of tractography errors and to identify axonal configurations that lead to such errors consistently, across dMRI acquisition and analysis strategies. We find that these common failure modes involve geometries such as branching or turning, which cannot be modeled well by crossing fibers. We also find that the default thresholds that are commonly used in tractography correspond to rather conservative, low-sensitivity operating points. While deterministic tractography tends to have higher sensitivity than probabilistic tractography in that very conservative threshold regime, the latter outperforms the former as the threshold is relaxed to avoid missing true anatomical connections. On the other hand, the q-space sampling scheme and maximum b-value have less of an impact on accuracy. Finally, using scans from a set of additional macaque brains, we show that there is enough inter-individual variability to warrant caution when dMRI and tracer data come from different animals, as is often the case in the tractography validation literature. Taken together, our results provide insights on the limitations of current tractography methods and on the critical role that anatomic tracing can play in identifying potential avenues for improvement.

Fluorescence Properties of a Novel Isoquinoline Derivative Tested in an Invertebrate Chordate, Ciona intestinalis.

3-Hydroxyisoquinolines (ISOs) and their tautomeric isoquinolin-3-ones are heterocycles with attractive biological properties. Here we reported the revisited synthesis of a highly functionalized ISO that showed blue fluorescence and the characterization of its biological properties in an invertebrate animal model, the ascidian Ciona intestinalis. Larvae exposed to ISO at concentrations higher than 1 µM showed an intense fluorescence localized in the cell nuclei of all tissues. Moreover, exposure to ISO interfered with larval ability to swim; this neuromuscular effect was reversible. Overall, these results suggested that ISOs can have promising applications as novel fluorescent dyes of the cell nuclei.

Selecting an anti-malarial clinical candidate from two potent dihydroisoquinolones.

BACKGROUND: The ongoing global malaria eradication campaign requires development of potent, safe, and cost-effective drugs lacking cross-resistance with existing chemotherapies. One critical step in drug development is selecting a suitable clinical candidate from late leads. The process used to select the clinical candidate SJ733 from two potent dihydroisoquinolone (DHIQ) late leads, SJ733 and SJ311, based on their physicochemical, pharmacokinetic (PK), and toxicity profiles is described. METHODS: The compounds were tested to define their physicochemical properties including kinetic and thermodynamic solubility, partition coefficient, permeability, ionization constant, and binding to plasma proteins. Metabolic stability was assessed in both microsomes and hepatocytes derived from mice, rats, dogs, and humans. Cytochrome P450 inhibition was assessed using recombinant human cytochrome enzymes. The pharmacokinetic profiles of single intravenous or oral doses were investigated in mice, rats, and dogs. RESULTS: Although both compounds displayed similar physicochemical properties, SJ733 was more permeable but metabolically less stable than SJ311 in vitro. Single dose PK studies of SJ733 in mice, rats, and dogs demonstrated appreciable oral bioavailability (60-100%), whereas SJ311 had lower oral bioavailability (mice 23%, rats 40%) and higher renal clearance (10-30 fold higher than SJ733 in rats and dogs), suggesting less favorable exposure in humans. SJ311 also displayed a narrower range of dose-proportional exposure, with plasma exposure flattening at doses above 200 mg/kg. CONCLUSION: SJ733 was chosen as the candidate based on a more favorable dose proportionality of exposure and stronger expectation of the ability to justify a strong therapeutic index to regulators.

A phase 1 pharmacokinetic study of oral NEPA, the fixed combination of netupitant and palonosetron, in Chinese healthy volunteers.

PURPOSE: Oral NEPA, the only fixed-combination antiemetic, is composed of the neurokinin-1 receptor antagonist netupitant (300 mg) and the 5-hydroxytryptamine-3 receptor antagonist palonosetron (0.50 mg). This study was conducted to evaluate the pharmacokinetic profile of netupitant and its main metabolites M1 and M3, and palonosetron in Chinese subjects. Oral NEPA tolerability and safety were also analyzed. METHODS: This was a single-center, single-dose phase 1 study in healthy, adult Chinese volunteers. Eligible subjects received oral NEPA, and blood samples were collected on day 1 predose and at various time points up until day 10 postdose. Pharmacokinetic parameters were analyzed using noncompartmental methods. For safety assessments, adverse events (AEs) were monitored during the study. RESULTS: In total 18 Chinese healthy volunteers received oral NEPA. Netupitant mean maximum plasma concentration (Cmax) [± standard deviation] of 698 ± 217 ng/mL was reached at 3-6 h, with a mean total exposure (AUC0-inf) of 22,000 ± 4410 h·ng/mL. For palonosetron, a mean Cmax of 1.8 ± 0.252 ng/mL was reached at 2-6 h postadministration, with a mean AUC0-inf of 81.0 ± 14.0 h·ng/mL. The most common treatment-related AEs in > 2 subjects were constipation (n = 9) and tiredness (n = 3). No severe AEs were observed, and no subject withdrew due to AEs. CONCLUSION: Following single-dose administration of oral NEPA in Chinese subjects, the pharmacokinetic profiles of the NEPA components were mostly similar to those reported previously in Caucasians. NEPA was well tolerated with a safety profile in line with that observed in pivotal trials in Caucasians.

An In Vitro and In Vivo Evaluation of the Effect of Relacorilant on the Activity of Cytochrome P450 Drug Metabolizing Enzymes.

Relacorilant is a selective modulator of the glucocorticoid receptor in development for the treatment of several serious diseases. The widely used cocktail method was employed to assess relacorilant's effect on various cytochrome P450 (CYP) drug metabolizing enzymes in vitro and in vivo. Inhibition of CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2B6, CYP2C8, CYP3A4, and CYP3A5 as well as induction of CYP1A2, CYP2B6, and CYP3A4 were assessed in vitro (relacorilant concentrations up to 10 µM). A clinical study in healthy subjects (n = 27) evaluated the inhibition of CYP3A4, CYP2C8, and CYP2C9 in vivo by administering single doses of probe CYP substrates (midazolam, pioglitazone, and tolbutamide) alone and in combination with relacorilant (350 mg). Pharmacokinetic sampling was conducted, and safety was assessed throughout the study. Pharmacokinetic parameters were evaluated using 90% confidence intervals of the geometric least squares mean ratios of test (probe substrate with relacorilant) vs reference (probe substrate alone) using boundaries of 80% to 125%. In vitro, relacorilant inhibited CYP3A4, CYP2C8, and CYP2C9 but did not meaningfully affect the activity of the other CYP enzymes evaluated. Consistent with the in vitro data, relacorilant was shown to be a strong CYP3A inhibitor in vivo (>8-fold increase in midazolam area under the concentration versus time curve from time zero to the last quantifiable concentration and area under the concentration versus time curve from time zero extrapolated to infinity). Coadministration of relacorilant with drugs highly dependent on CYP3A for clearance is expected to increase the concentrations of these drugs. Importantly, clinical evaluation of relacorilant showed no inhibition of CYP2C8 or CYP2C9 in vivo. Accordingly, drugs that are substrates of only CYP2C8 and/or CYP2C9 can be coadministered with relacorilant without dose adjustment.

Validated HPLC-UV method for simultaneous quantification of phosphatidylinositol 3-kinase inhibitors, copanlisib, duvelisib and idelalisib, in rat plasma: Application to a pharmacokinetic study in rats.

Phosphatidylinositol 3-kinase (PI3K) inhibitors are a novel class of anticancer drugs that are approved to treat various malignancies. We report the development and validation of a HPLC method for the simultaneous quantitation of three PI3K inhibitors, namely copanlisib, duvelisib and idelalisib, in rat plasma as per the regulatory guidelines of the United States Food and Drug Administration. The method involves extraction of copanlisib, duvelisib and idelalisib along with an internal standard (IS; filgotinib) from rat plasma (100 µL) using a liquid-liquid extraction process. The chromatographic separation of the analytes was achieved using step-wise gradient elution on a Hypersil Gold C18 column. The UV detection wavelength was set at λmax = 280 nm. Copanlisib, duvelisib, idelalisib and the IS eluted at 7.16, 12.6, 11.9 and 9.86 min, respectively, with a total run time of 15 min. The calibration curve ranged from 50 to 5000 ng/mL for all the analytes. Inter- and intra-day precision and accuracy, stability studies, dilution integrity and incurred sample reanalysis were investigated for all three analytes, and the results met the acceptance criteria. The validated HPLC method was successfully applied to a pharmacokinetic study in rats.