Physiologically based pharmacokinetic (PBPK) modeling of pitavastatin in relation to SLCO1B1 genetic polymorphism.

Pitavastatin, a potent 3-hydroxymethylglutaryl coenzyme A reductase inhibitor, is indicated for the treatment of hypercholesterolemia and mixed dyslipidemia. Hepatic uptake of pitavastatin is predominantly occupied by the organic anion transporting polypeptide 1B1 (OATP1B1) and solute carrier organic anion transporter family member 1B1 (SLCO1B1) gene, which is a polymorphic gene that encodes OATP1B1. SLCO1B1 genetic polymorphism significantly alters the pharmacokinetics of pitavastatin. This study aimed to establish the physiologically based pharmacokinetic (PBPK) model to predict pitavastatin pharmacokinetics according to SLCO1B1 genetic polymorphism. PK-Sim® version 10.0 was used to establish the whole-body PBPK model of pitavastatin. Our pharmacogenomic data and a total of 27 clinical pharmacokinetic data with different dose administration and demographic properties were used to develop and validate the model, respectively. Physicochemical properties and disposition characteristics of pitavastatin were acquired from previously reported data or optimized to capture the plasma concentration-time profiles in different SLCO1B1 diplotypes. Model evaluation was performed by comparing the predicted pharmacokinetic parameters and profiles to the observed data. Predicted plasma concentration-time profiles were visually similar to the observed profiles in the non-genotyped populations and different SLCO1B1 diplotypes. All fold error values for AUC and Cmax were included in the two fold range of observed values. Thus, the PBPK model of pitavastatin in different SLCO1B1 diplotypes was properly established. The present study can be useful to individualize the dose administration strategy of pitavastatin in individuals with various ages, races, and SLCO1B1 diplotypes.

The Effect of Retroconversion Metabolism of N-oxide Metabolites by Intestinal Microflora on Piperaquine Elimination in Mice, as well as in Humans Predicted Using a PBPK Model.

BACKGROUND: Piperaquine (PQ) and its pharmacologically active metabolite PQ N-oxide (PM1) can be metabolically interconverted via hepatic cytochrome P450 and FMO enzymes. OBJECTIVES: The reductive metabolism of PM1 and its further N-oxidation metabolite (PM2) by intestinal microflora was evaluated, and its role in PQ elimination was also investigated. METHODS: The hepatic and microbial reduction metabolism of PM1 and PM2 was studied in vitro. The reaction phenotyping experiments were performed using correlation analysis, selective chemical inhibition, and human recombinant CYP/FMO enzymes. The role of microbial reduction metabolism in PQ elimination was evaluated in mice pretreated with antibiotics. The effect of the reduction metabolism on PQ exposures in humans was predicted using a physiologically-based pharmacokinetic (PBPK) model. RESULTS: Both hepatic P450/FMOs enzymes and microbial nitroreductases (NTRs) contributed to the reduction metabolism of two PQ N-oxide metabolites. In vitro physiologic and enzyme kinetic studies of both N-oxides showed a comparable intrinsic clearance by the liver and intestinal microflora. Pretreatment with antibiotics did not lead to a significant (P > 0.05) change in PQ pharmacokinetics in mice after an oral dose. The predicted pharmacokinetic profiles of PQ in humans did not show an effect of metabolic recycling. CONCLUSION: Microbial NTRs and hepatic P450/FMO enzymes contributed to the reduction metabolism of PQ Noxide metabolites. The reduction metabolism by intestinal microflora did not affect PQ clearance, and the medical warning in patients with NTRs-related disease (e.g., hyperlipidemia) will not be clinically meaningful.

Efavirenz-Based Antiretroviral Therapy but Not Pregnancy Increased Unbound Piperaquine Exposure in Women during Malaria Chemoprevention.

Dihydroartemisinin-piperaquine (DP) is highly effective for malaria chemoprevention during pregnancy, but the standard dosing of DP that is used for nonpregnant adults may not be optimal for pregnant women. We previously reported that the pharmacokinetic exposure of total piperaquine (PQ; both bound and unbound to plasma proteins) is reduced significantly in the context of pregnancy or efavirenz (EFV)-based antiretroviral therapy (ART). However, as PQ is >99% protein-bound, reduced protein binding during pregnancy may lead to an increase in the pharmacologically active unbound drug fraction (fu), relative to the total PQ. We investigated the impact of pregnancy and EFV use on the fu of PQ to inform the interpretation of pharmacokinetics. Plasma samples from 0 to 24 h after the third (final) DP dose were collected from pregnant women at 28 weeks gestation who were receiving or not receiving EFV-based ART as well as from women 34 to 54 weeks postpartum who were not receiving EFV-based ART, who served as controls. Unbound PQ was quantified via ultrafiltration and liquid chromatography-tandem mass spectrometry, with fu being calculated as PQunbound/PQtotal. The geometric mean fu did not differ between pregnant and postpartum women (P = 0.66), but it was 23% (P < 0.01) greater in pregnant women receiving EFV-based ART, compared to that in postpartum women who were not receiving EFV-based ART. The altered drug-protein binding, potentially due to the displacement of PQ from plasma proteins by EFV, resulted in only a 14% lower unbound PQ exposure (P = 0.13) in the presence of a 31% lower total PQ exposure (P < 0.01), as estimated by the area under the concentration time curve from 0 to 24 h post-last dose in pregnant women who were receiving EFV-based ART. The results suggest that the impact of pregnancy and EFV-based ART on the exposure and, in turn, the efficacy of PQ for malaria prevention may not be as significant as was suggested by the changes in the total PQ exposure. Further study during the terminal elimination phase (e.g., on day 28 post-dose) would help better characterize the unbound PQ exposure during the full dosing interval and, thus, the overall efficacy of PQ for malaria chemoprevention in this special population.

Pharmacokinetic Interactions between Canagliflozin and Sorafenib or Lenvatinib in Rats.

Hepatocellular carcinoma (HCC) and type 2 diabetes mellitus (T2DM) are common clinical conditions, and T2DM is an independent risk factor for HCC. Sorafenib and lenvatinib, two multi-targeted tyrosine kinase inhibitors, are first-line therapies for advanced HCC, while canagliflozin, a sodium-glucose co-transporter 2 inhibitor, is widely used in the treatment of T2DM. Here, we developed an ultra-performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of canagliflozin, sorafenib, and lenvatinib, and investigated the pharmacokinetic drug interactions between canagliflozin and sorafenib or lenvatinib in rats. The animals were randomly divided into five groups. Groups I-III were gavage administrated with sorafenib, lenvatinib, and canagliflozin, respectively. Group IV received sorafenib and canagliflozin; while Group V received lenvatinib and canagliflozin. The area under the plasma concentration-time curves (AUC) and maximum plasma concentrations (Cmax) of canagliflozin increased by 37.6% and 32.8%, respectively, while the apparent volume of distribution (Vz/F) and apparent clearance (CLz/F) of canagliflozin significantly decreased (30.6% and 28.6%, respectively) in the presence of sorafenib. Canagliflozin caused a significant increase in AUC and Cmax of lenvatinib by 28.9% and 36.2%, respectively, and a significant decrease in Vz/F and CLz/F of lenvatinib by 52.9% and 22.7%, respectively. In conclusion, drug interactions exist between canagliflozin and sorafenib or lenvatinib, and these findings provide a reference for the use of these drugs in patients with HCC and T2DM.

Piperaquine Pharmacokinetic and Pharmacodynamic Profiles in Healthy Volunteers of Papua New Guinea after Administration of Three-Monthly Doses of Dihydroartemisinin-Piperaquine.

Mass drug administration (MDA) with monthly dihydroartemisinin-piperaquine (DHA-PQP) appears useful in malaria control and elimination strategies. Determining the relationship between consecutive piperaquine phosphate (PQP) exposure and its impact on QT interval prolongation is a key safety consideration for MDA campaigns. Healthy volunteers from Papua New Guinea received a 3-day course of DHA-PQP (2.1/17.1 mg/kg) monthly for 3 consecutive months in a single arm longitudinal study. Plasma PQP concentrations were measured after the third dose of each course (at 52-54 h) and at 0 h of course 3. Twelve-lead electrocardiographic readings were conducted at 0 h, 48 h, 52 h, and day 7 of each course. QT interval corrected by Fridericia's formula (QTcF) was measured at each time point. A pharmacokinetic-pharmacodynamic model using nonlinear mixed effects models was developed to correlate PQP concentrations with QTcF. Ten thousand female and 10,000 male individuals were simulated at each treatment course. Eighty-two participants were included; mean age was 28.3 years (standard deviation [SD] ±12.3 years), and 36 (44%) were female. Pharmacokinetic-pharmacodynamic models were determined with 290 PQP concentrations and 868 QTcF observations. The average baseline QTcF was 392 ms with a between-subject variability SD ±14.4 ms and between-occasion variability SD ±3.64 ms. From the population modeled, only 0.08% of males and 0.45% of females would be at risk of an absolute QTcF of >500 ms. DHA-PQP is safe at standard doses in consecutive months, and the likelihood of severe cardiac events occurring during an MDA campaign is very low. This study has been registered at ClinicalTrials.gov under identifier NCT02605720.

Distribution Pattern of the Monoamine Oxidase B Ligand, 18F-THK5351, in the Healthy Brain.

BACKGROUND: 18F-THK5351 PET estimates the concentrations of monoamine oxidase B (MAO-B) that are preferentially located in astrocytes and can be used to visualize and quantify ongoing astrogliosis. To study images of astrogliosis in neurological disorders, it is essential to understand the detailed binding sites of 18F-THK5351 as the MAO-B ligand under normal conditions. In this study, we examined the detailed distribution pattern of 18F-THK5351 in the healthy brain by comparing 18F-THK5351 uptake between subjects taking and not taking the MAO-B inhibitor. METHODS: Ten healthy controls (HCs: 67.4 [SD, 15.1] years) and 4 patients with Parkinson disease taking the MAO-B inhibitor underwent 18F-THK5351 PET. The uptake ratio index (URI) was defined to quantify 18F-THK5351 uptake, using the cerebellum as a reference region. The cerebellar URI was set to zero. RESULTS: For HCs, regions with URI ≥1 were preferentially observed in the following order: the striatum, globus pallidus, thalamus, hypothalamus, amygdala, periaqueductal gray, substantia nigra, medulla, hippocampus, and pons. The peak URI values in the corresponding regions were 2.93, 2.47, 2.12, 2.04, 1.84, 1.68, 1.67, 1.37, 1.20, and 1.11, respectively. For all patients with Parkinson disease taking the MAO-B inhibitor, the URI values in all these regions were significantly decreased (Z score >2) and were reduced from 60.4% to 99.9%, compared with HCs. CONCLUSIONS: This study presented the detailed distribution pattern of 18F-THK5351 in HCs and suggests that 18F-THK5351 uptake largely reflects MAO-B concentrations under normal conditions.

No Effect of PXR (8055C>T) Polymorphism on the Pharmacokinetic Profiles of Piperaquine in Healthy Chinese Subjects.

BACKGROUND: Significant inter-subject variability in pharmacokinetics and clinical outcomes has been observed for the antimalarial agent piperaquine (PQ). PQ is metabolized by CYP3A4, mainly regulated by the pregnane X receptor (PXR). CYP3A4(*1B) polymorphism did not affect PQ clearance. OBJECTIVES: The effect of PXR (8055C>T) polymorphism on the pharmacokinetic profiles of PQ was investigated. METHODS: The pharmacokinetic profiles of PQ and its major metabolite PQ N-oxide (PQM) were studied in healthy Chinese subjects after recommended oral doses of artemisinin-PQ. Twelve subjects were genotyped using PCRRFLP (six in each group with PXR 8055CC and 8055TT), and plasma concentrations were determined by a validated LC/MS/MS method. The dose-adjusted exposure (AUC and Cmax) to PQ or PQM was investigated, and the metabolic capability of PQ N-oxidation was determined by AUCPQM/AUCPQ. The antimalarial outcome of PQ was evaluated using its day 7 concentration. RESULTS: PQM formation was mediated by CYP3A4/3A5. Interindividual variability in dose-adjusted AUC of PQ and PQM was relatively low (%CV, <30.0%), whereas a larger inter-variability was observed for Cmax values (%CV, 68.1% for PQ). No polymorphic effect was found for PXR (C8055T) on the pharmacokinetic profiles of PQ or its Cday 7 concentrations. CONCLUSION: Both CYP3A4 and CYP3A5 were involved in PQ clearance. The genotypes of PXR (C8055T) may not contribute to the variability in PQ pharmacokinetics as well as antimalarial outcomes. There might be a low risk of variable exposures to PQ in malaria patients carrying mutated PXR (8055C>T) genes, which deserves further study, especially in a larger sample size.

A Simple UPLC/MS-MS Method for Simultaneous Determination of Lenvatinib and Telmisartan in Rat Plasma, and Its Application to Pharmacokinetic Drug-Drug Interaction Study.

Lenvatinib is a multi-targeted tyrosine kinase inhibitor that inhibits tumor angiogenesis, but hypertension is the most common adverse reaction. Telmisartan is an angiotensin receptor blocker used to treat hypertension. In this study, a simple ultra-performance liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of lenvatinib and telmisartan, and it was applied to the pharmacokinetic drug interaction study. Plasma samples were treated with acetonitrile to precipitate protein. Water (containing 5 mM of ammonium acetate and 0.1% formic acid) and acetonitrile (0.1% formic acid) were used as the mobile phases to separate the analytes with gradient elution using a column XSelect HSS T3 (2.1 mm × 100 mm, 2.5 µm). Multiple reaction monitoring in the positive ion mode was used for quantification. The method was validated and the precision, accuracy, matrix effect, recovery, and stability of this method were reasonable. The determination of analytes was not interfered with by other substances in the blank plasma, and the calibration curves of lenvatinib and telmisartan were linear within the range of 0.2-1000 ng/mL and 0.1-500 ng/mL, respectively. The results indicate that lenvatinib decreased the systemic exposure of telmisartan. Potential drug interactions were observed between lenvatinib and telmisartan.

Mechanistic Modeling of Primaquine Pharmacokinetics, Gametocytocidal Activity, and Mosquito Infectivity.

Clinical studies have shown that adding a single 0.25 mg base/kg dose of primaquine to standard antimalarial regimens rapidly sterilizes Plasmodium falciparum gametocytes. However, the mechanism of action and overall impact on malaria transmission is still unknown. Using data from 81 adult Malians with P. falciparum gametocytemia who received the standard dihydroartemisinin-piperaquine treatment course and were randomized to receive either a single dose of primaquine between 0.0625 and 0.5 mg base/kg or placebo, we characterized the pharmacokinetic-pharmacodynamic relationships for transmission blocking activity. Both gametocyte clearance and mosquito infectivity were assessed. A mechanistically linked pharmacokinetic-pharmacodynamic model adequately described primaquine and carboxy-primaquine pharmacokinetics, gametocyte dynamics, and mosquito infectivity at different clinical doses of primaquine. Primaquine showed a dose-dependent gametocytocidal effect that precedes clearance. A single low dose of primaquine (0.25 mg/kg) rapidly prevented P. falciparum transmissibility.

Simultaneous determination of febuxostat and montelukast in human plasma using fabric phase sorptive extraction and high performance liquid chromatography-fluorimetric detection.

In the present work, a new sensitive and selective high-performance liquid chromatography-fluorimetric detection (HPLC-FLD) method was developed and validated to quantify febuxostat (FBX) and montelukast (MON) in human plasma. The developed procedure was successfully applied to a study aimed at evaluating the pharmacokinetic profiles of febuxostat and montelukast in human plasma. A sol-gel poly (caprolactone)-block-poly(dimethylsiloxane)-block-poly(caprolactone) (sol-gel PCAP-PDMS-PCAP) extraction sorbent coated fabric phase sorptive extraction membrane was used in the extraction process. The entire chromatographic analysis was performed with isocratic elution of the composition of the mobile phase (acetonitrile:water, 60:40, v:v, 0.032% glacial acetic acid) on the C18 column. The flow rate is varied during the analysis, particularly from 0.5 mL min-1 at the start and linearly increased to 1.5 mL min-1 in 7 min. The detection and quantification of the analytes was carried out by means of a fluorimetric detector at 320 nm and 350 nm as absorption wavelengths and at 380 and 400 nm as emission wavelengths for FBX and MON, respectively. The calibration curves demonstrated linearity in the range 0.3-10 ng mL-1 and 5-100 ng mL-1 for FBX and MON, respectively, while the LOD and LOQ values were 0.1 and 0.3 ng mL-1 for FBX and 1.5 and 5 ng mL-1 for MON. Intraday and interday RSD% values were found lower than 5.79%. As reported, the method was applied to real plasma samples obtained from a volunteer who was co-administered both the drugs. Pharmacokinetic data reveal that the concentration of both the drugs reaches the plateau approximately at the same time, but exhibits an elimination phase at different rates. This study demonstrated the usefulness of the new method and its applicability in therapeutic drug monitoring (TDM).

Impact of genetic polymorphisms on the pharmacokinetics and pharmacodynamics of lenvatinib in patients with hepatocellular carcinoma.

This prospective study examined the impact of genetic polymorphisms on the pharmacokinetics and clinical efficacy and safety of lenvatinib, a substrate of ATP-binding transporters, in a cohort of 48 Japanese patients with hepatocellular carcinoma (HCC). Pharmacokinetic studies were performed at the start of lenvatinib therapy (day 1) and on day 15. The coefficients of variation in AUC0-24h of lenvatinib on days 1 and 15 were 44.0% and 52.4%, respectively. Although the ABCB1 3435C > A, 1236C > T, and 2677G>T/A polymorphisms did not influence pharmacokinetic parameters, the AUC0-24h values on days 1 and 15 of the ABCG2 C/A or A/A group were approximately 1.1-fold and 1.4-fold that in the ABCG2 C/C group (P = 0.164 and 0.024). There were no significant differences in AUC0-24h on days 1 and 15 between the responders (complete or partial response) and non-responders (stable or progressive disease). The AUC0-24h on day 15 in those developing anorexia of any grade was significantly higher than that without such development (P = 0.017). In multivariate analysis, ABCG2 421C > A C/A or A/A was significantly associated with the development of anorexia (odds ratio 9.009, P = 0.009). ABCG2 421C > A polymorphism could affect exposure to lenvatinib and the development of anorexia.

Identifying an optimal dihydroartemisinin-piperaquine dosing regimen for malaria prevention in young Ugandan children.

Intermittent preventive treatment (IPT) with dihydroartemisinin-piperaquine (DP) is highly protective against malaria in children, but is not standard in malaria-endemic countries. Optimal DP dosing regimens will maximize efficacy and reduce toxicity and resistance selection. We analyze piperaquine (PPQ) concentrations (n = 4573), malaria incidence data (n = 326), and P. falciparum drug resistance markers from a trial of children randomized to IPT with DP every 12 weeks (n = 184) or every 4 weeks (n = 96) from 2 to 24 months of age (NCT02163447). We use nonlinear mixed effects modeling to establish malaria protective PPQ levels and risk factors for suboptimal protection. Compared to DP every 12 weeks, DP every 4 weeks is associated with 95% protective efficacy (95% CI: 84-99%). A PPQ level of 15.4 ng/mL reduces the malaria hazard by 95%. Malnutrition reduces PPQ exposure. In simulations, we show that DP every 4 weeks is optimal across a range of transmission intensities, and age-based dosing improves malaria protection in young or malnourished children.

Development and in vitro evaluation of effervescent floating matrix tablet of neritinib: An anticancer drug.

Neratinib is a potent anticancer drug, used for the treatment of breast cancer. It is poorly soluble at higher pH, which tends to minimize the therapeutic effects in the lower GIT leads to its poor bioavailability. An attempt has been made to prepare and develop a novel gastro-retentive system of neratinib to improve the drug bioavailability in the GIT by enhancing the gastric retention time. The floating matrix tablets were prepared by various proportions of carbopol 940, micro-crystalline cellulose (MCC) and ethyl cellulose (EC), sodium bicarbonate (NaHCO3) as gas forming agent, by direct compression. The formulation mixture was assessed for pre and post compression test, lag time, in-vitro floating, FTIR, water uptake/swelling index, in vitro and kinetic release studies. The findings revealed that, the parameters of compression (pre and post) were within USP limits. The floating tablets swelled well and floated for more than 24h, with less than 120 seconds of buoyancy lag time. The optimized formulation F3 showed sustained release up to 12h; a non-Fickian mechanism. Therefore, all the results and findings have shown that developed neratinib floating matrix system is a promising approach as a drug delivery system and application in the treatment of breast cancer.

A Promising Single Oral Disintegrating Tablet for Co-Delivery of Pitavastatin Calcium and Lornoxicam Using Co-Processed Excipients: Formulation, Characterization and Pharmacokinetic Study.

SIGNIFICANCE: Statins are an important class of drugs that help to control hyperlipidemia, and one of these statins recently used is pitavastatin calcium (PITA). Nevertheless, the most reported adverse effect of statins is myopathy. Therefore, combining statins with non-steroidal anti-inflammatory drugs (NSAIDs) as Lornoxicam (LORNO) can help in the management of statin-induced myopathy. PURPOSE: This study aimed to formulate and evaluate different oral disintegrating tablets (ODTs) containing PITA using different co-processed excipients. The best PITA-ODT was selected and reformulated with the addition of LORNO, forming a single ODT comprising both drugs. The pharmacokinetic parameters of PITA and LORNO in a single ODT were compared to those of the marketed products (Lipidalon® and Lornoxicam®). METHODS: Eight PITA-ODTs were prepared via direct compression. The prepared PITA-ODTs were evaluated for their weight variation, thickness, breaking force, friability, drug content, and wetting time (WT). In-vitro disintegration time (DT) and dissolution were also evaluated and taken as parameters for selection of the best formula based on the criteria of scoring the fastest DT and highest Q10 min. LORNO was added to the selected PITA-ODT, forming a single ODT (M1) comprising both drugs, which was subjected to an in-vivo pharmacokinetic study using rats as an animal model and liquid chromatography-mass spectrometry (LC-MS/MS) for analysis of both drugs in rat plasma. RESULTS: Results showed that all PITA-ODTs had acceptable physical properties in accordance with pharmacospecial standards. PITA-ODT prepared with Pharmaburst® (F2) had significantly (p<0.05) the fastest DT (6.66±1.52 s) and highest Q10 min (79.07±2.02%) and was chosen as the best formula. The in-vivo pharmacokinetic study of M1 formula showed higher percent relative bioavailability (%RB) of 286.7% and 169.73% for PITA and LORNO, respectively, compared with the marketed products. CONCLUSION: The single ODT comprising PITA and LORNO was promising for instant co-delivery of both drugs with higher %RB when compared with the marketed products.

Metabolism is not a Major Contributor to the Toxicity of Piperaquine, a Long-acting Antimalarial Agent in Artemisinin-based Combination Therapy.

BACKGROUND: Hepatocellular damage has been reported for the antimalarial piperaquine (PQ) in the clinic after cumulative doses. OBJECTIVES: The role of metabolism in PQ toxicity was evaluated, and the mechanism mediating PQ hepatotoxicity was investigated. METHODS: The toxicity of PQ and its major metabolite (PQ N-oxide; M1) in mice was evaluated in terms of serum biochemical parameters. The role of metabolism in PQ toxicity was investigated in mice pretreated with an inhibitor of CYP450 (ABT) and/or FMO enzyme (MMI). The dose-dependent pharmacokinetics of PQ and M1 were studied in mice. Histopathological examination was performed to reveal the mechanism mediating PQ hepatotoxicity. RESULTS: Serum biochemical levels (ALT and BUN) increased significantly (P < 0.05) in mice after three-day oral doses of PQ (> 200 mg/kg/day), indicating hepatotoxicity and nephrotoxicity of PQ at a high dose. Weaker toxicity was observed for M1. Pretreatment with ABT and/or MMI did not increase PQ toxicity. PQ and M1 showed linear pharmacokinetics in mice after a single oral dose, and multiple oral doses led to their cumulative exposures. Histopathological examination showed that a high dose of PQ (> 200 mg/kg/day for three days) could induce hepatocyte apoptosis. The mRNA levels of targets in NF-κB and p53 pathways could be up-regulated by 2-30-fold in mice by PQ or M1. CONCLUSION: PQ metabolism led to detoxification of PQ, but there was a low possibility of altered toxicity induced by metabolism inhibition. The hepatotoxicity of PQ and its N-oxidation metabolite was partly mediated by NF-κB inflammatory pathway and p53 apoptosis pathway.

A Broad Range High-Throughput Assay for Lenvatinib Using Ultra-High Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry With Clinical Application in Patients With Hepatocellular Carcinoma.

BACKGROUND: Lenvatinib is increasingly being selected as the first-line treatment for unresectable hepatocellular carcinoma (HCC) based on the results of the REFLECT trial. However, early discontinuation of lenvatinib because of adverse effects is a frequent occurrence. Hence, lenvatinib is a difficult drug for use in the clinical setting. One of the causes is that the dose of lenvatinib is mainly determined by body weight alone, despite high interindividual variability. To overcome this problem, a dosing regimen of lenvatinib based on a population pharmacokinetic (PPK) model for HCC patients is proposed. The aim of this study was to develop a high-throughput quantification method for lenvatinib using ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) that can be applied to a PPK analysis of HCC patients in the future. METHODS: After a simple solid-phase extraction step using a 96-well plate, lenvatinib was analyzed by UHPLC-MS/MS in a positive electrospray ionization mode. RESULTS: The novel method fulfilled the requirements of the US Food and Drug Administration guidance on bioanalytical method validation. The calibration curve was linear over the 0.2-1000 ng/mL concentration range. The average recovery rate was 98.63 ± 4.55% (mean ± SD). The precision was below 6.05%, and the accuracy was within 12.96% for all quality control levels. The matrix effect varied between 103.33% and 134.61%. This assay was successfully applied to the measurement of plasma concentrations in 6 HCC patients receiving lenvatinib. CONCLUSIONS: A novel high-throughput UHPLC-MS/MS assay for quantification of lenvatinib in human plasma was successfully developed. This method can be applied to PPK analysis for patients receiving lenvatinib in the clinical setting.

Discovery of IDO1 inhibitors containing a decahydroquinoline, decahydro-1,6-naphthyridine, or octahydro-1H-pyrrolo[3,2-c]pyridine scaffold.

A series of IDO1 inhibitors containing a decahydroquinoline, decahydro-1,6-naphthyridine, or octahydro-1H-pyrrolo[3,2-c]pyridine scaffold were identified with good cellular and human whole blood activity against IDO1. These inhibitors contain multiple chiral centers and all diastereomers were separated. The absolute stereochemistry of each isomers were not determined. Compounds 15 and 27 stood out as leads due to their good cellular as well as human whole blood IDO1 inhibition activity, low unbound clearance, and reasonable mean residence time in rat cassette PK studies.

Pharmacokinetic Characterization and Bioavailability Barrier for the Key Active Components of Botanical Drug Antitumor B (ATB) in Mice for Chemoprevention of Oral Cancer.

This study aims to characterize the pharmacokinetic (PK) profiles and identify important bioavailability barriers and pharmacological pathways of the key active components (KACs) of Antitumor B (ATB), a chemopreventive agent. KACs (matrine, dictamine, fraxinellone, and maackiain) of ATB were confirmed using the antiproliferative assay and COX-2 inhibition activities in oral cancer cells. The observed in vitro activities of KACs were consistent with their cell signaling pathways predicted using the in silico network pharmacology approach. The pharmacokinetics of KACs were determined after i.v., i.p., and p.o. delivery using ATB extract and a mixture of four KACs in mice. Despite good solubilities and permeabilities, poor oral bioavailabilities were estimated for all KACs, mostly because of first-pass metabolism in the liver (for all KACs) and intestines (for matrine and fraxinellone). Multiple-dose PK studies showed 23.2-fold and 8.5-fold accumulation of dictamine and maackiain in the blood, respectively. Moreover, saliva levels of dictamine and matrine were found significantly higher than their blood levels. In conclusion, the systemic bioavailabilities of ATB-KACs were low, but significant levels of dictamine and matrine were found in saliva upon repeated oral administration. Significant salivary concentrations of matrine justified its possible use as a drug-monitoring tool to track patient compliance during chemoprevention trials.

Tumour-on-chip microfluidic platform for assessment of drug pharmacokinetics and treatment response.

Microphysiological in vitro systems are platforms for preclinical evaluation of drug effects and significant advances have been made in recent years. However, existing microfluidic devices are not yet able to deliver compounds to cell models in a way that reproduces the real physiological drug exposure. Here, we introduce a novel tumour-on-chip microfluidic system that mimics the pharmacokinetic profile of compounds on 3D tumour spheroids to evaluate their response to the treatments. We used this platform to test the response of SW620 colorectal cancer spheroids to irinotecan (SN38) alone and in combination with the ATM inhibitor AZD0156, using concentrations mimicking mouse plasma exposure profiles of both agents. We explored spheroid volume and viability as a measure of cancer cells response and changes in mechanistically relevant pharmacodynamic biomarkers (γH2AX, cleaved-caspase 3 and Ki67). We demonstrate here that our microfluidic tumour-on-chip platform can successfully predict the efficacy from in vivo studies and therefore represents an innovative tool to guide drug dose and schedules for optimal efficacy and pharmacodynamic assessment, while reducing the need for animal studies.

Amino-Substituted 3-Aryl- and 3-Heteroarylquinolines as Potential Antileishmanial Agents.

Leishmaniasis, a disease caused by protozoa of the Leishmania species, afflicts roughly 12 million individuals worldwide. Most existing drugs for leishmaniasis are toxic, expensive, difficult to administer, and subject to drug resistance. We report a new class of antileishmanial leads, the 3-arylquinolines, that potently block proliferation of the intramacrophage amastigote form of Leishmania parasites with good selectivity relative to the host macrophages. Early lead 34 was rapidly acting and possessed good potency against L. mexicana (EC50 = 120 nM), 30-fold selectivity for the parasite relative to the macrophage (EC50 = 3.7 µM), and also blocked proliferation of Leishmania donovani parasites resistant to antimonial drugs. Finally, another early lead, 27, which exhibited reasonable in vivo tolerability, impaired disease progression during the dosing period in a murine model of cutaneous leishmaniasis. These results suggest that the arylquinolines provide a fruitful departure point for the development of new antileishmanial drugs.