Plasma Pharmacokinetic Studies Research Articles

Validation of a LC-MS/MS method to simultaneously quantify thiafentanil and naltrexone in plasma for pharmacokinetic studies in wildlife

Thiafentanil is a popular opioid agonist that is fully reversed by administering naltrexone. This agonist–antagonist combination is administered to a wide variety of wildlife species for chemical immobilisation, however plasma concentrations for thiafentanil remain unreported. This report describes a method that was developed and validated using human plasma and cross-validated for the analysis of goat plasma. Samples were extracted using a simple protein precipitation and analysed using LC-MS/MS. The assay was validated over the calibration range 4.38 − 1120 ng/mL for thiafentanil and 15.63 − 4000 ng/mL for naltrexone. The mean inter-day accuracies for QCs prepared in human plasma (n = 18) ranged from 94.8 − 103.8 % for thiafentanil and 94.8 − 95.9 % for naltrexone with corresponding precisions of 3.4 − 7.9 % and 2.8 − 11.4 %, respectively. The mean accuracies for QCs prepared in goat plasma (n = 6) ranged from 89.0 − 100.5 % for thiafentanil and 89.0 − 98.0 % for naltrexone with the associated precisions ranging from 7.1 − 11.6 % and 4.8 − 12.3 %, respectively. Both analytes were stable on bench for six hours and for three freeze–thaw cycles. The impact of heat-inactivation, necessary for the inactivation of potential foot-and-mouth disease, on analyte stability, matrix effect and recovery were evaluated, and a correction factor was established to determine the original analyte concentrations. The method was applied to pharmacokinetic samples collected from goats. The use of goats as a model species provides the first insight into the plasma concentrations of thiafentanil.

Non-clinical pharmacokinetics study in rat plasma, tissues and excreta of honokiol derivative HM475 by UPLC-Q-TOF-MS/MS

To provide the basis for further development and research of drugs, non-clinical pharmacokinetics studies were conducted on HM475, which is composed of natural active molecules honokiol and metformin through cyclization. In this paper, HM475 was studied from six aspects by gavage and intraperitoneal injection: 1) Acute toxicity of HM475 in rats, 2) Pharmacokinetic characteristics of HM475 in rats, 3) Distribution characteristics of HM475 in heart, liver, spleen, lung, and kidney, small intestine, fat and brain of rats, 4) Main metabolic pathways of HM475 in rats, 5) Excretion of HM475 in rats, 6) Determination of protein binding rate of HM475 in bovine plasma, rabbit plasma, and rat plasma. Acute toxicity of HM475 on SD rats was evaluated by maximum dose method. The metabolic analysis method of HM475 in rats was first established by UPLC-Q-TOF-MS/MS technology, and the pharmacokinetic characteristics of oral administration and intraperitoneal injection were studied. Experimental results showed that HM475 had no obvious acute toxicity. The absolute oral bioavailability of HM475 was 38.45 %, and the drug concentration in plasma was higher than that in tissues. Combined with the process characteristics of HM475 in vivo, it is inferred that HM475 has enterohepatic circulation. In this study, non-clinical pharmacokinetics were systematically studied to provide data support for the clinical pharmacokinetics and pharmacodynamics of HM475, to more accurately predict the pharmacokinetic behavior of HM475 in human body and provide scientific data for the compound to enter clinical research.

Deconvolution of Plasma Pharmacokinetics from Dynamic Heart Imaging Data Obtained by Single Positron Emission Computed Tomography/Computed Tomography Imaging.

Plasma pharmacokinetic (PK) data are required as an input function for graphical analysis of single positron emission computed tomography/computed tomography (SPECT/CT) and positron emission tomography/CT (PET/CT) data to evaluate tissue influx rate of radiotracers. Dynamic heart imaging data are often used as a surrogate of plasma PK. However, accumulation of radiolabel in the heart tissue may cause overprediction of plasma PK. Therefore, we developed a compartmental model, which involves forcing functions to describe intact and degraded radiolabeled proteins in plasma and their accumulation in heart tissue, to deconvolve plasma PK of 125I-amyloid beta 40 (125I-Aβ 40) and 125I-insulin from their dynamic heart imaging data. The three-compartment model was shown to adequately describe the plasma concentration-time profile of intact/degraded proteins and the heart radioactivity time data obtained from SPECT/CT imaging for both tracers. The model was successfully applied to deconvolve the plasma PK of both tracers from their naïve datasets of dynamic heart imaging. In agreement with our previous observations made by conventional serial plasma sampling, the deconvolved plasma PK of 125I-Aβ 40 and 125I-insulin in young mice exhibited lower area under the curve than aged mice. Further, Patlak plot parameters extracted using deconvolved plasma PK as input function successfully recapitulated age-dependent plasma-to-brain influx kinetics changes. Therefore, the compartment model developed in this study provides a novel approach to deconvolve plasma PK of radiotracers from their noninvasive dynamic heart imaging. This method facilitates the application of preclinical SPECT/PET imaging data to characterize distribution kinetics of tracers where simultaneous plasma sampling is not feasible. SIGNIFICANCE STATEMENT: Knowledge of plasma pharmacokinetics (PK) of a radiotracer is necessary to accurately estimate its plasma-to-brain influx. However, simultaneous plasma sampling during dynamic imaging procedures is not always feasible. In the current study, we developed approaches to deconvolve plasma PK from dynamic heart imaging data of two model radiotracers, 125I-amyloid beta 40 (125I-Aβ 40) and 125I-insulin. This novel method is expected to minimize the need for conducting additional plasma PK studies and allow for accurate estimation of the brain influx rate.

Formulation of inclusion complex of Abiraterone acetate with 2-Hydroxypropyl-Beta-Cyclodextrin: physiochemical characterization, molecular docking and bioavailability evaluation

Abiraterone acetate is a steroid-based anti-androgen molecule approved in the year of 2011 for the therapy of patients suffering from metastatic prostate cancer. However, its physicochemical properties and therapeutic applications are limited by its lipophilic nature and low aqueous solubility. One of the most favourable and well-established methods of cyclodextrins (CDs) assisted inclusion complex was chosen to elevate the solubility-related pitfalls, chemical stability, and associated bioavailability issues of Abiraterone acetate (ABT). Several preparative methods like grinding, kneading, and freeze-drying were employed to fabricate the inclusion complex of ABT/2-hydroxypropyl-β-cyclodextrin (ABT-HP-β-CD). The freeze-drying assisted inclusion complex showed better physicochemical properties, which were investigated using DSC, TGA, PXRD, ATR-FTIR, FESEM, phase solubility, and molecular docking studies. All the above-said characterization studies performed exhibited the emergence of ABT-HP-β-CD. The inclusion complex existed in the stoichiometric ratio of 1:1 with the calculated stability constant (Ks) of 2385 M−1. The solubility of ABT was enhanced to 39-fold after complexation with HP-β-CD. Moreover, a molecular docking study confirmed that ABT was towards the core of HP-β-CD. The in vivo plasma pharmacokinetic studies demonstrated a higher solubility, absorption rate and 2.25-fold improved bioavailability than the free ABT group. This existing study revealed that HP-β-CD can be a notable molecule to fabricate a feasible and cost-effective inclusion complex for elevating the aqueous solubility, stability and in vivo pharmacokinetics of ABT.

Conveyance of sofosbuvir through vesicular lipid nanocarriers as an effective strategy for management of viral meningitis.

This study aimed to deliver a potential water-soluble antiviral drug (sofosbuvir) through optimized vesicular lipid nanocarriers (LNs) to the rat brain as a novel strategy against viral meningitis. A 23 factorial design approach was established to assess the effect of formulation composition and process variables on the physicochemical properties of the LNs. Sofosbuvir-loaded LNs (SLNs) were developed by lipid layer hydration method utilizing optimized parameters and evaluated for various in vitro characterizations like FTIR, DSC, XRD, FESEM, vesicle size, zeta potential, drug carrying capacity and drug release. Plasma and brain pharmacokinetic (PK) studies were conducted in Sprague-Dawley rats. FTIR data depicted the absence of any major interaction between the drug and the excipients. DSC revealed a sharp endothermic peak for the drug. XRD showed the amorphic nature of the SLNs. Optimized SLNs were spherical as depicted from FESEM with 42.43 nm size, -49.21 mV zeta potential, 8.31% drug loading and sustained drug release in vitro. Plasma/brain PK studies depicted significant improvement in key PK parameters, viz. AUC, AUMC, MRT, and Vd, compared to those for the free drug. A more than 3.5-fold increase in MRT was observed for optimized SLNs (11.2 h) in brain tissue compared to the free drug (3.7 h). Ex vivo hemolysis data confirmed the non-toxic nature of the SLNs to human red blood cells. In silico docking study further confirmed strong interaction between the drug and selected protein 4YXP (herpes simplex) with docking score of -7.5 and 7EWQ protein (mumps virus) with docking score of -7.3. The optimized SLNs may be taken for further in vivo studies to pave the way towards clinical translation.

Levosulpiride-loaded nanostructured lipid carriers for brain delivery with antipsychotic and antidepressant effects

AimsHerein, we investigate the potential of levosulpiride-loaded nanostructured lipid carriers (LEVO-NLCs) for effective brain delivery with anti-psychotic and antidepressant effects. Main methodsMicro-emulsion method was used to prepare LEVO-NLCs, followed by its optimization using Design Expert®, investigation of the particles properties and entrapment efficiency (%EE). Moreover, in-vitro release, in-vivo plasma and brain kinetic studies of LEVO-NLCs were executed. Anti-psychotic activity of LEVO-NLCs was accomplished in LPS-induced psychosis mice model. Additionally, expressions of neuro inflammatory mediators, neurodegeneration and neuro-inflammation in brain tissues was investigated. Key findingsThe optimized LEVO-NLCs were rounded shaped nanoparticles (157.2 nm) with suitable zeta potential (−29.6 mV), low PDI (0.395) and high EE (83.67 %). No chemical interactions were found, however, the crystalline drug was changed to amorphous. LEVO-NLCs displayed sustained drug release behavior when compared with drug suspension. Moreover, a meaningfully higher AUC (106,642.27 ± 876.44 ng.h/mL) and Cmax (38,534.72 ± 2344.10 ng/mL) of the LEVO-NLCs in brain was observed as compared to the AUC (15,684.33 ± 1005.49 ng.h/mL) and Cmax (7717.56 ± 871.23 ng/mL) of LEVO-Suspension. Similar profiles of both the formulations were perceived in plasma pharmacokinetic studies. Furthermore, LEVO-NLCs exhibited a meaningfully improved anti-psychotic activity in LPS-induced psychosis mice model with reduced immobility time and enhanced struggling time. Likewise, treatment with LEVO-NLCs showed reduced levels of neuro inflammatory markers (p-NF-κB and COX-2) in LPS-induced mice. Additionally, no neuro-degeneration and neuro-inflammation in brain tissues treated with LEVO-NLCs mice group was detected. SignificanceThese results concluded that NLCs may effectively be used for the brain delivery of various active pharmaceutical agents with enhanced biopharmaceutical performance.

CNS penetration of methotrexate and its metabolite 7-hydroxymethotrexate in mice bearing orthotopic Group 3 medulloblastoma tumors and model-based simulations for children

The brain penetration of methotrexate (MTX) and its metabolite 7-hydroxymethotrexate (7OHMTX) was characterized in non-tumor bearing mice and mice bearing orthotopic Group 3 medulloblastoma. Plasma pharmacokinetic studies and cerebral and ventricular microdialysis studies were performed in animals dosed with 200 or 1000 mg/kg MTX by IV bolus. Plasma, brain/tumor extracellular fluid (ECF) and lateral ventricle cerebrospinal fluid (CSF) MTX and 7OHMTX concentration-time data were analyzed by validated LC-MS/MS methods and modeled using a population-based pharmacokinetic approach and a hybrid physiologically-based model structure for the brain compartments. Brain penetration was similar for MTX and 7OHMTX and was not significantly different between non-tumor and tumor bearing mice. Overall, mean (±SD) model-derived unbound plasma to ECF partition coefficient Kp,uu were 0.17 (0.09) and 0.17 (0.12) for MTX and 7OHMTX, respectively. Unbound plasma to CSF Kp,uu were 0.11 (0.06) and 0.18 (0.09) for MTX and 7OHMTX, respectively. The plasma and brain model were scaled to children using allometric principles and pediatric physiological parameters. Model-based simulations were adequately overlaid with digitized plasma and CSF lumbar data collected in children receiving different MTX systemic infusions. This model can be used to further explore and optimize methotrexate dosing regimens in children with brain tumors.

Accurate Mass Identification of an Interfering Water Adduct and Strategies in Development and Validation of an LC-MS/MS Method for Quantification of MPI8, a Potent SARS-CoV-2 Main Protease Inhibitor, in Rat Plasma in Pharmacokinetic Studies.

MPI8, a peptidyl aldehyde, is a potent antiviral agent against coronavirus. Due to unique tri-peptide bonds and the formyl functional group, the bioassay of MPI8 in plasma was challenged by a strong interference from water MPI8. Using QTOF LC-MS/MS, we identified MPI8•H2O as the major interference form that co-existed with MPI8 in aqueous and biological media. To avoid the resolution of MPI8 and MPI8•H2O observed on reverse phase columns, we found that a Kinetex hydrophilic interaction liquid chromatography (HILIC) column provided co-elution of both MPI8 and MPI8•H2O with a good single chromatographic peak and column retention of MPI8 which is suitable for quantification. Thus, a sensitive, specific, and reproducible LC-MS/MS method for the quantification of MPI8 in rat plasma was developed and validated using a triple QUAD LC-MS/MS. The chromatographic separation was achieved on a Kinetex HILIC column with a flow rate of 0.4 mL/min under gradient elution. The calibration curves were linear (r2 > 0.99) over MPI8 concentrations from 0.5–500 ng/mL. The accuracy and precision are within acceptable guidance levels. The mean matrix effect and recovery were 139% and 73%, respectively. No significant degradation of MPI8 occurred under the experimental conditions. The method was successfully applied to a pharmacokinetic study of MPI8 after administration of MPI8 sulfonate in rats.

Pharmacokinetic Study of Abacavir Sulphate Loaded Niosomes and Proniosomes in Rats

The plasma pharmacokinetic study of abacavir sulphate was investigated after oral administration of free abacavir sulphate solution, freshly prepared niosomal and proniosomal abacavir sulphate dispersions. The abacavir sulphate loaded niosome vesicles were prepared by the thin-film hydration method and proniosomes were prepared by the slurry method using tween 60 as surfactant cholesterol as a membrane stabilizer and dicetyl phosphate as a negative charge inducer. Maltodextrin was used as a carrier in the proniosome formulations. The formulations were evaluated for various evaluation parameters such as drug-polymer interaction, phase identification analysis and in vivo pharmacokinetic study. The comparative pharmacokinetics of free, niosome encapsulated and proniosome encapsulated abacavir sulphate was evaluated in rats at a dose of 8.57 mg/kg of abacavir sulphate. The results of niosome and proniosome encapsulated abacavir sulphate showed a significant increase in bioavailability and prolonged release characteristics. Increased half-life of 3.40 h in the case of niosomes and 4.88 h in the case of proniosomes were observed. Based on the results, it can be concluded that niosomal and proniosomal formulation could be a promising delivery system for abacavir sulphate with improved oral bioavailability and prolonged drug release profiles.

Enzyme-linked immunosorbent assays for quantification of MMAE-conjugated ADCs and total antibodies in cynomolgus monkey sera

Antibody-drug conjugates (ADCs) are commonly heterogeneous and require extensive assessment of exposure-efficacy and exposure-safety relationships in preclinical and clinical studies. In this study, we report the generation of a monoclonal antibody against monomethyl auristatin E (MMAE) and the development, validation, and application of sensitive and high-throughput enzyme-linked immunosorbent assays (ELISA) to measure the concentrations of MMAE-conjugated ADCs and total antibodies (tAb, antibodies in ADC plus unconjugated antibodies) in cynomolgus monkey sera. These assays were successfully applied to in vitro plasma stability and pharmacokinetic (PK) studies of SMADC001, an MMAE-conjugated ADC against trophoblast cell surface antigen 2 (TROP-2). The plasma stability of SMADC001 was better than that of similar ADCs coupled with PEG4-Val-Cit, Lys (m-dPEG24)-Cit, and Val-Cit linkers. The developed ELISA methods for the calibration standards of ADC and tAb revealed a correlation between serum concentrations and the OD450 values, with R2 at 1.000, and the dynamic range was 0.3–35.0 ng/mL and 0.2–22.0 ng/mL, respectively; the intra- and inter-assay accuracy bias% ranged from −12.2% to −5.2%, precision ranged from −12.4% to −1.4%, and the relative standard deviation (RSD) was less than 6.6% and 8.7%, respectively. The total error was less than 20.4%. The development and validation steps of these two assays met the acceptance criteria for all addressed validation parameters, which suggested that these can be applied to quantify MMAE-conjugated ADCs, as well as in PK studies. Furthermore, these assays can be easily adopted for development of other similar immunoassays.

Design and evaluation of thermo-responsive nasal in situ gelling system dispersed with piribedil loaded lecithin-chitosan hybrid nanoparticles for improved brain availability

Piribedil (PBD) is a compound that has shown efficacy in clinical trials to treat motor and non-motor symptoms of Parkinson's disease. However, drug delivery issues like low oral bioavailability, high dosing frequency (3–5 tablets/day), gastrointestinal side-effects reduced the clinical use of PBD. In this work, we have developed lecithin-chitosan hybrid nanoparticles (PBD-LCNs) to improve the direct nose to brain uptake of PBD. PBD-LCNs were optimized using hybrid design approach based on DoE. The mean particle size and drug loading of PBD-LCNs were 147 nm, and 12%, respectively. The PBD-LCNs showed good stability and were found to be nearly spherical in shape. Further, the optimized LCNs were loaded in methylcellulose thermo-responsive in situ gel (PBD-LCN-ISG) to overcome rapid mucociliary clearance upon intranasal administration. Plasma and brain pharmacokinetic studies in rats showed that PBD-LCN-ISG increased the relative bioavailability of PBD in brain (AUCbrain) by about 6.4-folds and reduced the (Cmax)plasma by 3.7-folds when compared to plain intranasal suspension of PBD (PBD-Susp). Further, PBD-Susp showed limited direct nose to brain uptake with DTP values less than 0, while the optimized PBD-LCNs showed DTP value of 56% indicating efficient direct nose to brain uptake. Overall, the development of nanoformulations significantly improved the direct nose to brain uptake of PBD.This article is part of the special Issue on ‘Stress, Addiction and Plasticity'.

Pharmacokinetic Parameters and Tissue Withdrawal Intervals for Sheep Administered Multiple Oral Doses of Meloxicam.

Simple SummaryMeloxicam is an anti-inflammatory drug used to treat pain and inflammation in ruminants including sheep, and pharmacokinetic studies are needed to protect the food supply from drug residues after use in food-producing animals. This study estimated plasma pharmacokinetic parameters and meat withdrawal intervals (WDI) for market sheep after multiple daily oral doses of meloxicam. Single and multiple dose plasma pharmacokinetic studies, a multi-dose tissue depletion study, and a follow-up study to investigate if events prior to slaughter were associated with differences in plasma meloxicam concentrations, all using sample data collected after completion of dosing, were completed. Using regulatory agency methods for calculating withdrawal times, an estimated WDI of at least 10 d following the last dose is recommended for market lambs treated with ten daily oral 1 mg/kg doses of meloxicam tablets suspended in water. The effect of events surrounding slaughter on plasma meloxicam concentrations in lambs is unknown but should be considered if plasma samples are obtained immediately prior to or during the slaughter process and used for pharmacokinetic investigations.Meloxicam is an anti-inflammatory drug used to treat pain and inflammation in ruminants including sheep, and pharmacokinetic studies are needed to protect the food supply from drug residues after use in food-producing animals. This study estimated plasma pharmacokinetic parameters and meat withdrawal intervals (WDI) for market sheep after multiple daily oral doses of meloxicam. Single and multiple dose plasma pharmacokinetic studies, a multi-dose tissue depletion study, and a follow-up study to investigate if events prior to slaughter were associated with differences in plasma meloxicam concentrations, all using sample data collected after completion of dosing, were completed. Using regulatory agency methods for calculating withdrawal times, an estimated WDI of at least 10 d following the last dose is recommended for market lambs treated with 10 daily oral 1 mg/kg doses of meloxicam tablets suspended in water. The effect of events surrounding slaughter on plasma meloxicam concentrations in lambs is unknown but should be considered if plasma samples are obtained immediately prior to or during the slaughter process and used for pharmacokinetic investigations.

Abstract 1073: Preclinical tissue biodistribution and plasma pharmacokinetic studies with oxaliTEX, a novel platinum(IV)-based oxaliplatin prodrug

Abstract Purpose: OxaliTEX is a texaphyrin-platinum(IV) prodrug with the ability to deliver the oxaliplatin payload to cisplatin-resistant tumor cells and restore wild-type p53 activation. As a result, the conjugate overcomes both multifactorial mechanisms of cisplatin resistance and transport-defective mechanism of oxaliplatin resistance. In an effort to prepare for translational studies, we have explored its distribution and pharmacokinetics (PK) in mice. Experimental Procedures: Athymic male and/or female nude mice (3-4/group), with or without subcutaneously implanted (flank) HCT-116 colon xenograft, received oxaliplatin (4 mg/kg) and an equimolar (17 mg/kg) or a similar therapeutic (50 mg/kg) dose of oxaliTEX iv. After 24 hours, mice were exsanguinated under anesthesia and plasma and tissues isolated. A separate group of female mice received oxaliTEX (50 mg/kg) and blood was taken at multiple times over the next 24 hours, plasma isolated and samples denatured to prepare protein-free supernatant (PFS) representing “free” platinum. Samples were analyzed for platinum (Pt) by flameless atomic absorption spectrophotometry. Results: At equimolar doses, gross sex differences in plasma or tissue concentrations were not observed for either drug. However, plasma Pt levels with oxaliTEX (0.6-0.7 ng Pt/ml) were 7-fold greater than with oxaliplatin (0.08-0.1 ng/ml). Similarly, a 3-fold greater concentration was also noted in liver (~1.4 vs. ~0.4 ng/mg) and heart (~0.5 vs. ~0.15 ng/mg) from mice treated with the prodrug. Tissues with ≤2-fold differences between the drugs in Pt levels were testes, kidney, ovary, lung, ileum and spleen, with undetectable levels in brain. In female mice bearing HCT-116 xenografts, the general tissue distribution pattern of each drug at the therapeutic dose was unchanged and demonstrated that increasing the oxaliTEX dose resulted in proportionate increase in tissue Pt levels. Notably, tumor Pt levels were ~5-fold greater with the conjugate (oxaliTEX, 1.1 ng Pt/mg; oxaliplatin, 0.21 ng/mg). PK analysis revealed that Pt in plasma and PFS was detectable for the entire 24 hr period and decayed in a biphasic manner, with respective α-phase half-life of 0.07 and 0.2 hr and β-phase half-life of 27 and 11 hr. The AUC in plasma and PFS was 172 and 3.7 μg.hr/ml, respectively. Conclusions: Results suggest that oxaliTEX is sequestered in the plasma by protein binding, leaving low-level systemic exposure to “free” non-protein bound Pt. Since the tissue levels are greater than oxaliplatin at equimolar and/or therapeutic doses in specific organs, this suggests that the low level exposure to “free” Pt contributes to drug tolerance of normal tissues, whereas the tumor-targeting design feature contributes to greater tumor uptake that enhances antitumor effects. Funding was provided by Cancer Prevention and Research Institute of Texas Citation Format: Guangan He, Gregory Thiabaud, Kathyrin A. Shelton, Luke J. Segura, Jonathan L. Sessler, Rick A. Finch, Zahid H. Siddik, Jonathan F. Arambula. Preclinical tissue biodistribution and plasma pharmacokinetic studies with oxaliTEX, a novel platinum(IV)-based oxaliplatin prodrug [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1073.

Minibeam radiation therapy enhanced tumor delivery of PEGylated liposomal doxorubicin in a triple-negative breast cancer mouse model.

Background:Minibeam radiation therapy is an experimental radiation therapy utilizing an array of parallel submillimeter planar X-ray beams. In preclinical studies, minibeam radiation therapy has been shown to eradicate tumors and cause significantly less damage to normal tissue compared to equivalent radiation doses delivered by conventional broadbeam radiation therapy, where radiation dose is uniformly distributed.Methods:Expanding on prior studies that suggested minibeam radiation therapy increased perfusion in tumors, we compared a single fraction of minibeam radiation therapy (peak dose:valley dose of 28 Gy:2.1 Gy and 100 Gy:7.5 Gy) and broadbeam radiation therapy (7 Gy) in their ability to enhance tumor delivery of PEGylated liposomal doxorubicin and alter the tumor microenvironment in a murine tumor model. Plasma and tumor pharmacokinetic studies of PEGylated liposomal doxorubicin and tumor microenvironment profiling were performed in a genetically engineered mouse model of claudin-low triple-negative breast cancer (T11).Results:Minibeam radiation therapy (28 Gy) and broadbeam radiation therapy (7 Gy) increased PEGylated liposomal doxorubicin tumor delivery by 7.1-fold and 2.7-fold, respectively, compared to PEGylated liposomal doxorubicin alone, without altering the plasma disposition. The enhanced tumor delivery of PEGylated liposomal doxorubicin by minibeam radiation therapy is consistent after repeated dosing, is associated with changes in tumor macrophages but not collagen or angiogenesis, and nontoxic to local tissues. Our study indicated that the minibeam radiation therapy’s ability to enhance the drug delivery decreases from 28 to 100 Gy peak dose.Discussion:Our studies suggest that low-dose minibeam radiation therapy is a safe and effective method to significantly enhance the tumor delivery of nanoparticle agents.

Intracellular vincristine levels in lymphoblasts affect treatment outcome in childhood B‐lymphoblastic leukaemia: Ma‐Spore ALL 2010 study

Vincristine (VCR) is a key drug in the successful multidrug chemotherapy for childhood acute lymphoblastic leukaemia (ALL). However, it remains unclear how VCR pharmacokinetics affects its antileukaemic efficacy. The objective of this study is to explore the VCR pharmacokinetic parameters and intracellular VCR levels in an up-front window of Ma-Spore ALL 2010 (MS2010) study. We randomised 429 children with newly diagnosed ALL to 15-minute vs 3-hour infusion for the first dose of VCR to study if prolonging the first dose of VCR infusion improved response. In a subgroup of 115 B-ALL and 20 T-ALL patients, we performed VCR plasma (n = 135 patients) and intracellular (n = 66 patients) pharmacokinetic studies. The correlations between pharmacokinetic parameters and intracellular VCR levels with early treatment response, final outcome and ABCB1 genotypes were analysed. There was no significant difference between 15-minute and 3-hour infusion schedules in median Day 8 peripheral or bone marrow blast response. Plasma VCR pharmacokinetic parameters did not predict outcome. However, in B-ALL, Day 33 minimal residual disease (MRD) negative patients and patients in continuous complete remission had significantly higher median intracellular VCR24h levels (P = .03 and P = .04, respectively). The median VCR24h intracellular levels were similar among the common genetic subtypes of ALL (P = .4). Patients homozygous for wild-type ABCB1 2677GG had significantly higher median intracellular VCR24h (P = .04) than 2677TT. We showed that in childhood B-ALL, the intracellular VCR24h levels in lymphoblasts affected treatment outcomes. The intracellular VCR24h level was independent of leukaemia subtype but dependent on host ABCB1 G2677T genotype.

Predicting Resolvin D1 Pharmacokinetics in Humans with Physiologically-Based Pharmacokinetic Modeling.

Sjögren’s syndrome (SS) is an autoimmune disease with no effective treatment options. Resolvin D1 (RvD1) belongs to a class of lipid‐based specialized pro‐resolving mediators that showed efficacy in preclinical models of SS. We developed a physiologically‐based pharmacokinetic (PBPK) model of RvD1 in mice and optimized the model using plasma and salivary gland pharmacokinetic (PK) studies performed in NOD/ShiLtJ mice with SS‐like features. The predictive performance of the PBPK model was also evaluated with two external datasets from the literature reporting RvD1 PKs. The PBPK model adequately captured the observed concentrations of RvD1 administered at different doses and in different species. The PKs of RvD1 in virtual humans were predicted using the verified PBPK model at various doses (0.01–10 mg/kg). The first‐in‐human predictions of RvD1 will be useful for the clinical trial design and translation of RvD1 as an effective treatment strategy for SS.

Pharmacokinetics and biotransformation investigation in beagle dog of active compounds from naoxintong capsule

Naoxintong Capsule (NXTC), a standardized herbal medicine, has been widely applied in treating cardiovascular and cerebrovascular diseases with remarkable efficacy. However, the efficacy contributing components of NXTC are unclear, and the in vivo absorption and metabolism processes of NXTC remain largely obscured. In this study, using beagle dog as model species, we have identified and tentatively characterized 25 prototype and 15 catabolites of NXTC in beagle dog plasma by ultra-fast liquid chromatography/quadrupole-time-of-flight tandem mass spectrometry (UFLC-Q-TOF-MS/MS). We have proposed the in vivo bio-transformation pathways of these absorbed constituents. In addition, for six crucial components, we have developed a quantitative method and conducted plasma pharmacokinetic study of these six components by rapid resolution liquid chromatography tandem triple quadrupole mass spectrometry (RRLC-QQQ-MS/MS). In conclude, our study provided comprehensive insights into the understanding of the plasma absorbed components profiling of NXTC as well as their in vivo transformation behaviors, which would be of great value for identifying efficacy contributing critical components as well as mechanism related investigations of NXTC in the future.

Withdrawal Notice: Synergistic Effect of Myricetin and Phenolic Acid Derivatives on the Reversal of Dengue Fever Related Thrombocytopenia and its Pharmacokinetics study in Plasma by using HPLC and UPLC-Q-TOF

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Oral administration of eugenol oleate cures experimental visceral leishmaniasis through cytokines abundance

Visceral leishmaniasis (VL) is an endemic fatal infectious disease in tropical and subtropical nations. The limited treatment options, long treatment regimens, invasive mode of administration of drugs, and lack of effective vaccination are the main reasons for the search of new alternative therapeutics against VL. On this quest, from a series of eugenol derivatives, we had demonstrated eugenol oleate as a lead immunomodulatory anti-VL molecule earlier. In this report, the oral efficacy and mechanism of eugenol oleate in inducing immunomodulatory anti-VL activity has been studied in BALB/c mice model. The plasma pharmacokinetic and acute toxicity studies suggested that the eugenol oleate is safe with an appreciable pharmacokinetic profile. Eugenol oleate (30 mg/kg B.W.) showed 86.5% of hepatic and 84.1% of splenic parasite clearance. The increased Th1 cytokine profile and decreased Th2 cytokine profile observed from ELISA and qRTPCR suggested that the eugenol oleate induced the parasite clearance through the activation of the host immune system. Subsequently, the mechanistic insights behind the anti-leishmanial activity of eugenol oleate were studied in peritoneal macrophages in vitro by inhibitor response study and immunoblotting. The results inferred that eugenol oleate activated the PKC-βII–p38 MAPK and produced IL-12 and IFN-γ which intern activated the iNOS2 to produce NO free radicals that cleared the intracellular parasite.

Thermoreversible Switchlike Electrocatalytic Reduction of Tizanidine Based on a Graphene Oxide Tethered Stimuli-Responsive Smart Surface Supported Pd Catalyst.

In this work, a graphene oxide (GRO)-based temperature-sensitive smart catalytic support material was developed by tethering biodegradable and hydrophilic poly(N-vinylcaprolactam) (PVCL) on a GRO (i.e., GRO-PVCL) surface. GRO-PVCL-supported palladium catalyst (i.e., Pd/GRO-PVCL) was then prepared for tizanidine (TZN) electroreduction. The impact of a temperature-sensitive smart surface on the electrochemical and electrocatalytic properties was examined. Moreover, when the large surface area, excellent electron transfer, and electrochemical catalysis abilities of GRO were combined with the responsive characteristics of PVCL, temperature-triggered reversible electrocatalysis of TZN with enhanced sensitivity has been proved. Results designated that GRO-PVCL exposed the hydrophilic surface at 20 °C, resulting in Pd NPs highly dispersed on the GRO-PVCL surface. Subsequently, the wettability of the Pd catalyst surface arbitrarily adapted to hydrophobicity at 40 °C, which highly enhanced the TZN reduction on the catalyst in electrochemical detection. The synergistic effect amid Pd and GRO-PVCL on Pd/GRO-PVCL improved the electrocatalytic activity of TZN. The detection of TZN with the Pd/GRO-PVCL modified electrode ranged from 0.02 to 276 μM with a low detection limit of 0.0015 μM at 40 °C. The Pd/GRO-PVCL modified electrode also possesses excellent stability, reproducibility, and anti-interference ability. Lastly, the modified electrode attained good recovery results in human urine and human plasma samples for the determination of TZN and also pharmacokinetics study in rat plasma.