Plasma Exposure Research Articles

Prediction of Pharmacokinetic Drug-Drug Interactions Involving Anlotinib as a Victim by Using Physiologically Based Pharmacokinetic Modeling.

Anlotinib was approved as a third line therapy for advanced non-small cell lung cancer in China. However, the impact of concurrent administration of various clinical drugs on the drug-drug interaction (DDI) potential of anlotinib remains undetermined. As such, this study aims to evaluate the DDI of anlotinib as a victim by establishing a physiologically based pharmacokinetic (PBPK) model. The PBPK model of anlotinib as a victim drug was constructed and validated in the Simcyp® incorporating parameters derived from in vitro studies, pre-clinical investigations, and clinical research encompassing patients with cancer. Subsequently, plasma exposure of anlotinib in cancer patients was predicted for single- and multi-dose co-administration with typical perpetrators mentioned in Food and Drug Administration (FDA) industrial guidance. Based on predictions, the CYP3A potent inhibitor ketoconazole demonstrated the most significant DDI with anlotinib, regardless of whether anlotinib is administered as a single dose or multiple doses. Ketoconazole increased the area under the concentration-time curve (AUC) and maximum concentration (Cmax) of single-dose anlotinib to 1.41-fold and 1.08-fold, respectively. In contrast, rifampicin, a potent inducer of CYP3A enzymes, exhibited a relatively higher level of DDI, with AUCR and CmaxR values of 0.44 and 0.79, respectively. Based on the PBPK modeling, there is a low risk of DDI between anlotinib and potent CYP3A/1A2 inhibitors, but caution and enhanced monitoring for adverse reactions are advised. To mitigate the risk of anti-tumor treatment failure, it is recommended to avoid concurrent use of strong CYP3A inducers. In conclusion, our study enhances understanding of anlotinib's interaction with medications, aiding scientists, prescribers, and drug labels in gauging the expected impact of CYP3A/1A2 modulators on anlotinib's pharmacokinetics.

Survey of tungsten gross erosion from main plasma facing components in WEST during a L-mode high fluence campaign

An initial high fluence campaign was performed in WEST, in 2023, on the newly installed actively cooled tungsten divertor composed of ITER-grade monoblocks. The campaign consisted in the repetition of a 60 s long Deuterium L-mode pulse in attached divertor conditions, cumulating over 10000s of plasma exposure. A maximum deuterium fluence of approximately 5⋅1026m−2 was reached in the outer strike point region, representative of a few high performance ITER pulses. Gross tungsten erosion inferred from visible spectroscopy shows that the most eroded plasma facing component is the inner divertor target with rates ten times larger than on the outer divertor target. The outer midplane tungsten bumpers, located a few centimeters from the plasma, show gross erosion rates two times lower than at the outer divertor. We conclude that the outer midplane bumpers have a negligible contribution to the long range tungsten migration and deposition onto the lower divertor. The cumulated gross erosion rate on the inner divertor translates in an effective gross erosion thickness of about 20μm, while it is about 2μm for the outer divertor. Strikingly, these orderings coincide with the thickness of deposits found locally on the divertor : the exposed surfaces of high field side monoblocks are covered with several tens of μm tungsten deposits, while on the lower field side, few μm thin tungsten deposits are only found on the magnetically shadowed parts of monoblocks. The strong impact of those deposits on WEST operation, namely perturbation of surface temperature measurement with infra-red thermography, and the emission of flakes causing radiative perturbation of the confined plasma, calls for anticipating similar issues in ITER. In particular, the start of research operation shall consider the definition of a divertor erosion budget in order to anticipate the formation of deleterious deposits.

Disposition of orally administered atuliflapon, a novel 5-lipoxygenase-activating protein inhibitor in healthy participants.

In this study, the mass balance, pharmacokinetics (PK) and metabolism of atuliflapon, a novel 5-lipoxygenase-activating protein inhibitor, were investigated in healthy male subjects. A single oral dose of 200 mg [14C]atuliflapon suspension was administered to six healthy male subjects. Mass balance, PK and metabolite profiles of atuliflapon were analyzed using radioactivity monitoring and liquid chromatography with mass spectrometry analysis. The safety of atuliflapon was assessed during the study. Atuliflapon was rapidly absorbed with a median tmax of 1.5 h, followed by a biphasic decline in plasma exposure rendering a terminal half-life of ~20 h. Unchanged atuliflapon was the predominant radioactive component in plasma, accounting for 40.1% of the total drug-related exposure (DRE), while a direct N-glucuronide was the only metabolite exceeding 10% of DRE, accounting for 20.9%. Renal excretion of intact atuliflapon accounted for <1% of the administered dose. In total 85.2% of administered radioactivity was recovered over 312 h with 79.3% and 5.9% in feces and urine, respectively. Parent atuliflapon contributed to approximately 40% of the recovered dose in excreta, while metabolites resulting from phase 1 oxidative pathways accounted for more than 30% of the excreted dose. Overall, a single oral dose of 200 mg [14C]atuliflapon suspension was well tolerated in healthy male subjects. The human metabolism and disposition data obtained will support future development and submissions of atuliflapon as a potential candidate drug for the treatment of cardiovascular, cardiorenal, and respiratory indications.

A randomised crossover design study comparing the pharmacokinetics and pharmacodynamics of two single Doses of ORal Aspirin (75 mg v 150mg) in pregnant women at risk of pre-eclampsia (DORA): implications on assessing aspirin response and patient adherence to therapy.

BackgroundPregnancy is associated with physiological changes that can alter the pharmacokinetic and pharmacodynamic profile of many drugs. Low-dose aspirin is used for pre-eclampsia (PE) prevention; however aspirin's pharmacokinetics and pharmacodynamics are poorly studied in pregnant women. ObjectiveThe aim of this study was to compare the pharmacodynamics of two common doses of aspirin (75 and 150 mg) used for PE prevention in high-risk women by examining their effect on thromboxane B2 (TbxB2) inhibition. A secondary objective sought to assess if salicylic acid could be used as means to evaluate adherence to aspirin. Study DesignFourteen pregnant women from a large maternity unit in England, eligible for prophylactic aspirin according to NICE guidance, were recruited into 2 x 2 randomised crossover trial. Blood samples were collected at baseline, 1, 2, 3, 4, 15, 16, 17, 18 and 19-hours post ingestion of either 75 or 150 mg of aspirin with a 7-day washout period. Plasma concentrations of salicylic acid (SA), the primary metabolite of aspirin, were determined using high performance liquid chromatography. Pharmacodynamic response to aspirin was assessed by measuring serum thromboxane B2 (TbxB2) concentrations by an enzyme-linked immunosorbent assay. Analyte data were compared using nonparametric test statistics for paired values (Wilcoxon Signed Rank Test) and areas under serum SA concentration versus time curve (AUC). Pharmacokinetic modelling was used to bridge the data arising from the overnight sampling break.The trial was registered with the ISRCTN (reg number ISRCTN14693054). ResultsA single dose of 150 mg of aspirin produced higher plasma exposure of SA in comparison to 75 mg (median SA AUC0-19 16.7 μg*h/ml (IQR 15.2-19.3) vs 6.8 μg*h/ml (IQR 6.1- 8.3), p<0.001). Pharmacokinetic models suggest that plasma SA concentrations could be detected above the maximum concentration recorded at baseline for the first 11 hours after 75 mg and for 12 hours after 150 mg aspirin dosing, providing a time frame to confirm recent aspirin ingestion. The 150 mg aspirin dose produced a greater normalised reduction in serum TbxB2 (median normalised reduction 95.7% (IQR 92.6%- 97.3%) than the 75 mg dose (median normalised reduction 84.6% (IQR 77.3-92.3%), p<0.007. ConclusionCompared to the 75 mg dose, 150 mg of aspirin more effectively inhibits TbxB2, providing rationale for further investigation of effectiveness of higher doses for pre-eclampsia prevention. Despite limitations, measuring serum SA concentration could still be used in future models to test adherence if done within 11-12 hours after ingestion.

Exposure of cumulative atherogenic index of plasma and the development of prediabetes in middle-aged and elderly individuals: evidence from the CHARLS cohort study

BackgroundThe impact of dynamic changes in the degree of atherosclerosis on the development of prediabetes remains unclear. This study aims to investigate the association between cumulative atherogenic index of plasma (CumAIP) exposure during follow-up and the development of prediabetes in middle-aged and elderly individuals.MethodsA total of 2,939 prediabetic participants from the first wave of the China Health and Retirement Longitudinal Study (CHARLS) were included. The outcomes for these patients, including progression to diabetes and regression to normal fasting glucose (NFG), were determined using data from the third wave. CumAIP was calculated as the ratio of the average AIP values measured during the first and third waves to the total exposure duration. The association between CumAIP and the development of prediabetes was analyzed using multivariable Cox regression and restricted cubic spline (RCS) regression.ResultsDuring a median follow-up period of 3 years, 15.21% of prediabetic patients progressed to diabetes, and 22.12% regressed to NFG. Among the groups categorized by CumAIP quartiles, the proportion of prediabetes progressing to diabetes gradually increased (Q1: 10.61%, Q2: 13.62%, Q3: 15.65%, Q4: 20.95%), while the proportion regressing to NFG gradually decreased (Q1: 23.54%, Q2: 23.71%, Q3: 22.18%, Q4: 19.05%). Multivariable-adjusted Cox regression showed a significant positive linear correlation between high CumAIP exposure and prediabetes progression, and a significant negative linear correlation with prediabetes regression. Furthermore, in a stratified analysis, it was found that compared to married individuals, those who were unmarried (including separated, divorced, widowed, or never married) had a relatively higher risk of CumAIP-related diabetes.ConclusionCumAIP is closely associated with the development of prediabetes. High CumAIP exposure not only increases the risk of prediabetes progression but also hinders its regression within a certain range. These findings suggest that monitoring and maintaining appropriate AIP levels may help prevent the deterioration of blood glucose levels.

Extrapolation of Upadacitinib Efficacy in Juvenile Idiopathic Arthritis Leveraging Pharmacokinetics, Exposure-Response Models, and Real-World Patient Data.

Juvenile idiopathic arthritis (JIA) is the most prevalent pediatric rheumatic disease. While disease-modifying antirheumatic drugs (DMARDs), especially biologics, have greatly transformed the management of JIA, there remain some unmet medical needs that require new treatment options. The objective of this work was to describe and apply a modeling and simulation approach to extrapolate upadacitinib efficacy from the adult diseases, rheumatoid arthritis (RA) and psoriatic arthritis (PsA), to their respective pediatric diseases, polyarticular course JIA (pcJIA), and juvenile PsA (JPsA). A population pharmacokinetic model characterized upadacitinib pharmacokinetics in pediatric patients using data from two phase I studies in pediatric patients with pcJIA (N = 51) or atopic dermatitis (N = 33). Efficacy simulations were conducted using previously developed exposure-response models in adults with RA and PsA. Real-world pcJIA and JPsA patient databases were leveraged to construct representative patient profiles for the targeted population. Following administration of the proposed weight-based dosing regimen, the model-predicted median upadacitinib plasma exposures in pediatric patients were within 20% of those in adult RA and PsA patients receiving the approved adult regimen. Simulations demonstrate that upadacitinib efficacy in pcJIA and JPsA is predicted to be non-inferior to that in adults with RA or PsA, respectively. The results of this work enabled recent approvals of upadacitinib for the treatment of polyarticular JIA and JPsA in the United States. Upadacitinib safety in pediatrics is being further evaluated in ongoing clinical trials.

The processing mechanism of vinegar-processed Curcumae Rhizome enhances anti hepatic fibrotic effects through regulation of PI3K/Akt/mTOR signaling pathway

BackgroundHepatic fibrosis, a chronic pathological condition resulting from various forms of persistent liver injury, in the later stage, it can evolve into cirrhosis and even liver cancer. Curcumae Rhizoma (CR), traditionally recognized for its properties in line qi break blood, eliminate accumulation and relieve pain. According to traditional Chinese medicine (TCM) principles, vinegar-processing enhances CR's ability to enter the liver meridian and act on the blood level, potentially augmenting its therapeutic effects on hepatic diseases. Therefore, vinegar-processed Curcumae Rhizoma (VCR) is frequently employed in treating liver fibrosis and related hepatic conditions. However, the underlying mechanisms of vinegar processing in enhancing its therapeutic efficacy remain unclear. MethodsThe anti-liver fibrosis effects of CR and VCR were verified at individual and cellular levels. Subsequently, HPLC-Q-TOFMS and pharmacokinetic analysis were utilized to elucidate the potential bioactive substances underlying the enhanced anti-fibrotic efficacy of VCR. Building upon these findings, network pharmacology and metabolomics were integrated to screen for key effect components and regulatory pathways. Finally, the mechanisms of action were further analyzed and validated at the tissue and cellular levels through Western blotting (WB) and molecular docking studies. ResultsBoth CR and VCR exhibited therapeutic effects against hepatic fibrosis, with VCR demonstrating enhanced efficacy after vinegar processing. 6 sesquiterpenes including furanodiene and curdione, showed significant alterations in plasma exposure and hepatic distribution post-processing. VCR significantly improved pathological liver conditions, lipid accumulation, and fibrosis severity. Additionally, VCR markedly reduced the expression of α-SMA in the liver and attenuated the elevations in liver function markers such as ALT and AST. Combined network pharmacology, metabolomics, and hepatic tissue WB analysis revealed that the reduced phosphorylation of the PI3K/Akt/mTOR pathway is a critical mechanism in VCR's anti-fibrotic effects. Experiments on LX-2 cells demonstrated that four sesquiterpenes, including furanodiene and curdione, effectively inhibited the proliferation of activated hepatic stellate cells (HSCs). Furanodiene, in particular, promoted apoptosis in activated HSCs by reducing phosphorylation levels of the PI3K/Akt/mTOR pathway proteins, increasing BAX expression, and activating downstream caspase-3 to achieve the effect of anti-liver fibrosis. ConclusionVinegar-processing significantly increases the plasma exposure and hepatic distribution of components such as furanodiene in VCR, enhancing anti-fibrotic efficacy by downregulating the phosphorylation levels of the PI3K/Akt/mTOR pathway and promoting HSC apoptosis. This study provides a comprehensive explanation of the vinegar-processing mechanism and its role in enhancing the anti-fibrotic effects of VCR, offering insights for its clinical application in liver fibrosis treatment and reference for the mechanistic study of other vinegar-processed herbal medicines.

Metabolite Measurement in Index Substrate Drug Interaction Studies: A Review of the Literature and Recent New Drug Application Reviews.

Index substrates are used to understand the processes involved in pharmacokinetic (PK) drug-drug interactions (DDIs). The aim of this analysis is to review metabolite measurement in clinical DDI studies, focusing on index substrates for cytochrome P450 (CYP) enzymes, including CYP1A2 (caffeine), CYP2B6 (bupropion), CYP2C8 (repaglinide), CYP2C9 ((S)-warfarin, flurbiprofen), CYP2C19 (omeprazole), CYP2D6 (desipramine, dextromethorphan, nebivolol), and CYP3A (midazolam, triazolam). All data used in this evaluation were obtained from the Certara Drug Interaction Database. Clinical index substrate DDI studies with PK data for at least one metabolite, available from literature and recent new drug application reviews, were reviewed. Further, for positive DDI studies, a correlation analysis was performed between changes in plasma exposure of index substrates and their marker metabolites. A total of 3261 individual index DDI studies were available, with 45% measuring at least one metabolite. The occurrence of metabolite measurement in clinical DDI studies varied widely between index substrates and enzymes. For substrates such as caffeine, bupropion, omeprazole, and dextromethorphan, the use of the metabolite/parent area under the curve ratio can provide greater sensitivity to DDI or reduce intrasubject variability. In some cases (e.g., omeprazole, repaglinide), the inclusion of metabolite measurement can provide mechanistic insights to understand complex interactions.

Deuterium plasma induced preferential erosion in ultra-high temperature ceramics TiB2 and ZrB2*

Abstract Steady-state deuterium plasma exposures were performed on ultra-high temperature ceramics titanium diboride (TiB2) and zirconium diboride (ZrB2) using the PISCES-RF linear plasma device (LPD) as early screening for first wall, plasma-facing applications. Deuterium plasma exposures were performed using 40 eV ion energies at 240, 525, and 800 °C sample temperatures and 90 eV ion energies at 240 °C sample temperatures to analyze TiB2 and ZrB2 surface morphology and chemistry evolution behavior. Post-plasma exposure chemistry characterization of the near surface ( &lt; 50 nm) region of the samples all show transition metal enrichment, indicating boron preferential erosion. Transition metal to boron fractions vary with plasma exposure temperature under the 40 eV ion energy; metal enrichment is maximized at 800 °C and then minimized at 525 °C. SEM micrographs of all plasma exposed sample surfaces show no significant or noticeable plasma induced damage from cracking or blistering.

Brain Exposure to the Macrocyclic ALK Inhibitor Zotizalkib is Restricted by ABCB1, and Its Plasma Disposition is Affected by Mouse Carboxylesterase 1c.

Zotizalkib (TPX-0131), a fourth-generation macrocyclic anaplastic lymphoma kinase (ALK) inhibitor, is designed to overcome resistance due to secondary ALK mutations in non-small cell lung cancer (NSCLC). We here evaluated the pharmacokinetic roles of the ABCB1 (P-gp/MDR1) and ABCG2 (BCRP) efflux transporters, OATP1 influx transporters and the metabolizing enzymes CES1 and CYP3A in plasma and tissue disposition of zotizalkib after oral administration in relevant mouse models. Zotizalkib was efficiently transported by hABCB1 in vitro. In vivo, a significant ∼9-fold higher brain-to-plasma ratio was observed in Abcb1a/b-/- and Abcb1a/b;Abcg2-/- compared to wild-type mice. No change in brain disposition was observed in Abcg2-/- mice, suggesting that mAbcb1a/b markedly restricts the brain accumulation of zotizalkib. ABCB1-mediated efflux of zotizalkib was completely inhibited by elacridar, a dual ABCB1/ABCG2 inhibitor, increasing brain exposure without any signs of acute CNS-related toxicities. In Oatp1a/b-/- mice, no marked changes in plasma exposure or tissue-to-plasma ratios were observed, indicating that zotizalkib is not a substantial in vivo substrate for mOatp1a/b. Zotizalkib may further be metabolized by CYP3A4 but only noticeably at low plasma concentrations. In Ces1-/- mice, a 2.5-fold lower plasma exposure was seen compared to wild-type, without alterations in tissue distribution. This suggests increased plasma retention of zotizalkib by binding to the abundant mouse plasma Ces1c. Notably, the hepatic expression of human CES1 did not affect zotizalkib plasma exposure or tissue distribution. The obtained pharmacokinetic insights may be useful for the further development and optimization of therapeutic efficacy and safety of zotizalkib and related compact macrocyclic ALK inhibitors.

Pharmacokinetics of anti-TB drugs in children and adolescents with drug-resistant TB: a multicentre observational study from India

Abstract Background Drug-resistant tuberculosis (DR-TB) is one of the challenging forms of TB to treat, not only in adults but also in children and adolescents. Further, there is a void in the treatment strategy exclusively for children due to various reasons, including paucity of pharmacokinetic (PK) data on anti-TB drugs across the globe. In this context, the present study aimed at assessing the PK of some of the anti-TB drugs used in DR-TB treatment regimens. Method A multicentre observational study was conducted among DR-TB children and adolescents (n = 200) aged 1–18 years (median: 12 years; IQR: 9–14) treated under programmatic settings in India. Steady-state PK (intensive: n = 89; and sparse: n = 111) evaluation of moxifloxacin, levofloxacin, cycloserine, ethionamide, rifampicin, isoniazid and pyrazinamide was carried out by measuring plasma levels using HPLC methods. Results In the study population, the frequency of achieving peak plasma concentrations ranged between 13% (for rifampicin) to 82% (for pyrazinamide), whereas the frequency of suboptimal peak concentration for pyrazinamide, cycloserine, moxifloxacin, levofloxacin and rifampicin was 15%, 19%, 29%, 41% and 74%, respectively. Further, the frequency of supratherapeutic levels among patients varied between 3% for pyrazinamide and 60% for isoniazid. In the below-12 years age category, the median plasma maximum concentration and 12 h exposure of moxifloxacin were significantly lower than that of the above-12 years category despite similar weight-adjusted dosing. Conclusions Age significantly impacted the plasma concentration and exposure of moxifloxacin. The observed frequencies of suboptimal and supratherapeutic concentrations underscore the necessity for dose optimization and therapeutic drug monitoring in children and adolescents undergoing DR-TB treatment.

Oxygen Plasma‐Induced Modification of Structural and Electrical Properties of Pr0.5Sr0.5MnO3 Manganites

Herein, the impact of exposing the perovskite compound Pr0.5Sr0.5MnO3 to oxygen plasma is explored by comparing the structural and transport properties of the exposed samples to those of the unexposed ones. The Pr is oxidized to PrO2 in the investigated samples due to plasma exposure. The alterations in the transport properties can be linked to the changes in MnOMn bond angle and MnO bond length due to plasma exposure, as indicated by X‐ray diffraction analysis. Additionally, exposure to oxygen plasma increases the conductivity by incorporating oxygen into the exposed samples, making them oxygen‐rich. Detailed analysis of the resistivity and thermoelectric power data indicates that small polarons are responsible for conduction at high temperatures, while at low temperatures, variable range polarons take over. The negative value of the thermopower at all temperatures proclaims that the electrons behave as the dominant charge carriers.

Fabrication, Microstructure and Plasma Resistance Behavior of Y-Al-Si-O (YAS) Glass-Ceramics Coated on Alumina Ceramics.

This study investigates the fabrication, microstructural characteristics and plasma resistance of Y-Al-Si-O (YAS) glass-ceramics coated on alumina ceramics. YAS frits were initially prepared using a melt-quenching method, then homogenously milled and coated onto alumina ceramics. The melt-coating process was conducted at 1650 °C for 1 h. The composition and microstructure of the glass frits and coatings were thoroughly characterized using X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. These analyses revealed a dense microstructure with a polycrystalline structure predominantly composed of Y3Al5O12 (YAG) phase and a minor phase of Y2Si2O7. The YAS coatings on alumina revealed a dense layer with strong adhesion to the substrate. Subsequently, the coatings underwent C4F6/Ar/O2 plasma treatment for 1 h. Plasma exposure tests demonstrated that the YAS-coated alumina exhibited significantly better etching resistance compared to uncoated alumina, with minimal surface damage observed on the YAS coating, confirming its protective properties against plasma. The superior plasma resistance of YAS coatings is attributed to the predominance of its YAG phase. This research offers a more stable and cost-efficient solution for protecting ceramics in demanding plasma environments.

Evaluation of the Potential for Cytochrome P450 and Transporter-Mediated Drug-Drug Interactions for Firsocostat, a Liver-Targeted Inhibitor of Acetyl-CoA Carboxylase.

Firsocostat is an oral, liver-targeted inhibitor of acetyl-CoA carboxylase in clinical development for the treatment of metabolic dysfunction-associated steatohepatitis. This work evaluated the potential drug-drug interactions (DDIs) of firsocostat as a victim and as a perpetrator, to inform concomitant medication use. In this phase I study, healthy participants (n=13-30 in each of four cohorts) received firsocostat alone or in combination with either victims or perpetrators of cytochrome P450 (CYP) enzymes and drug transporters to evaluate firsocostat as both a victim and perpetrator of DDIs, respectively. Overall, 80 participants completed the study. As a victim of DDI, firsocostat plasma exposure (area under the plasma concentration-time curve [AUC] from 0 to infinity [AUC∝]) was 19-fold, 22-fold, 63%, and 38% higher when administered with single-dose rifampin 600 mg (organic anion transporting polypeptide [OATP] 1B1/B3 inhibitor), single-dose cyclosporine A 600 mg (OATP/P-glycoprotein/CYP3A inhibitor), multiple-dose probenecid 500 mg twice daily (evaluated as a uridine diphosphate glucuronosyltransferase [UGT] inhibitor), and multiple-dose voriconazole 200 mg twice daily (CYP3A inhibitor), respectively, compared with the administration of firsocostat alone. As a perpetrator of DDI, multiple-dose administration of firsocostat did not affect the exposure of midazolam 2 mg (CYP3A substrate) or drospirenone/ethinylestradiol 3 mg/0.02 mg (combined oral contraceptive). Study treatments were well-tolerated and all adverse events were mild. Firsocostat can be administered with CYP3A and UGT inhibitors without dose adjustment. However, firsocostat should not be coadministered with strong OATP1B/3 inhibitors, such as rifampin and cyclosporine A. Firsocostat can be administered with CYP3A substrates or combined oral contraceptives without dose modification.

Lateral stress induced blistering of tungsten exposed to deuterium plasma

Surface blistering on tungsten under deuterium plasma exposure has been well known and investigated intensively in the last decade. However, the mechanism of the blistering is still unclear. There have been mainly two different models proposed: the gas driven model and lateral stress model. In this work, we designed an experiment to address this issue. Tungsten disc samples were prepared using twin-jet electro-polishing. The specimens were under deuterium plasma exposure to study the thickness effect on the surface blistering. The results showed that blistering was rarely observed on the surface around the inner edge of the central perforation with thickness of ∼100–500 nm. The blisters started to appear on the surface when the thickness was about 10 μm. Both the number and size of the blisters increased further on the outer surface with further increase in thickness. This trend was not obvious as the thickness increased up to above 180 μm. The diffusion depth of D in this work was calculated to be 8.5 μm. These results affirmed the lateral stress model as the surface blistering mechanism.

Inhibitory effects of calcium channel blockers nisoldipine and nimodipine on ivacaftor metabolism and their underlying mechanism.

Ivacaftor is the first potentiator of the cystic fibrosis transmembrane conductance regulator (CFTR) protein approved for use alone in the treatment of cystic fibrosis (CF). Ivacaftor is primarily metabolized by CYP3A4 and therefore may interact with drugs that are CYP3A4 substrates, resulting in changes in plasma exposure to ivacaftor. The study determined the levels of ivacaftor and its active metabolite M1 by ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). We screened 79 drugs and 19 severely inhibited ivacaftor metabolism, particularly two cardiovascular drugs (nisoldipine and nimodipine). In rat liver microsomes (RLM) and human liver microsomes (HLM), the half-maximal inhibitory concentrations (IC50) of nisoldipine on ivacaftor metabolism were 6.55μM and 9.10μM, respectively, and the inhibitory mechanism of nisoldipine on ivacaftor metabolism was mixed inhibition; the IC50 of nimodipine on ivacaftor metabolism in RLM and HLM were 4.57μM and 7.15μM, respectively, and the inhibitory mechanism of nimodipine on ivacaftor was competitive inhibition. In pharmacokinetic experiments in rats, it was observed that both nisoldipine and nimodipine significantly altered the pharmacokinetic parameters of ivacaftor, such as AUC(0-t) and CLz/F. However, this difference may not be clinically relevant. In conclusion, this paper presented the results of studies investigating the interaction between these drugs and ivacaftor in vitro and in vivo. The objective is to provide a rationale for the safety of ivacaftor in combination with other drugs.

Precision defect integrated graphene as reliable support membrane for high-resolution cryo-transmission electron microscopy

Graphene is an excellent support film for high-resolution transmission electron microscopy (TEM) but its use with biological samples, notably in cryo-TEM, is hindered by its inherent hydrophobicity. Whereas surface treatments have been proposed to render graphene hydrophilic, they are often difficult to reproduce due to a lack of information on the structural changes that modify the wetting properties of graphene. This study aims to correlate the atomic structure of graphene with its wetting properties to allow a reproducible protocol to advance its application in cryo-TEM. We follow the change in the atomic structure of graphene as a function of low-energy hydrogen plasma treatment duration on monolayer graphene transferred onto TEM grids. With finely controlled plasma exposure, partial hydrogenation, monoatomic vacancies, and pores of a few nanometers are realized in the graphene. The introduction of defects (vacancies and pores) enables the formation of continuous layers of vitreous ice on TEM grids. Grids with defect-integrated graphene are reproduced and used in the vitrification of the mouse serotonin 5-HT3 receptor, a membrane protein. Single particle analysis of the membrane protein on graphene compared to conventional holey carbon film give insight into the strengths and discretions in using graphene membrane for protein structural studies.

Application of Physiologically Based Pharmacokinetic Model to Delineate the Impact of Aging and Renal Impairment on Ceftazidime Clearance.

The impact of physiological changes during aging on drug disposition has not always been thoroughly assessed in clinical studies. This has left an open question such as how and to what extent patho- and physiological changes in renal function can affect pharmacokinetics in the geriatric population. The objective of this work was to use a physiologically based pharmacokinetic (PBPK) model to quantify the impact of aging and renal impairment (RI) separately and together on ceftazidime pharmacokinetics (PK). The predicted plasma concentrations and PK parameters from the PBPK model were compared to the observed data in individuals of different ages with or without RI (16 independent studies were investigated in this analysis). Apart from clearance in one study, the predicted ceftazidime PK parameters of young adults, elderly, and in individuals with different levels of renal function were within 2-fold of the observed data, and the observed concentrations fell within the 5th-95th prediction interval from the PBPK model simulations. The PBPK model predicted a 1.2-, 1.5-, and 1.8-fold increase in the plasma exposure (AUC) ratio in individuals aged 40, 60, and 70 years old, respectively, with normal renal function for their age compared to 20-year-old individuals with normal renal function. The impact of RI on ceftazidime was predicted to be less marked in older individuals (a 1.04-, 1.43-, and 2.55-fold change in mild, moderate, or severe RI compared to a healthy age-matched control) than in younger individuals (where a 1.47-, 2.03-, and 3.50-fold increase was predicted in mild, moderate, or severe RI compared to a healthy age-matched control). Utilization of the applied population-based PBPK approach allows delineation of the effects of age from renal disease and can better inform future study design and dosing recommendations in clinical study of elderly patients depending on their age and renal function.

Formation of YOF on Y2O3 through surface modification with NH4F and its plasma-resistance behavior

Yttrium oxyfluoride (YOF) is known for exhibiting superior plasma-resistance properties compared to Y2O3, particularly in a fluorocarbon plasma environment. The formation of the YOF layer directly on the surface of Y2O3 via surface modification may be considered as a viable and cost-effective method. In this study, we employed ammonium fluoride (NH4F) salt for the surface modification of Y2O3. By using a 40 wt% NH4F aqueous salt solution, the YOF layer with a thickness of about 8.6 μm was efficaciously formed in-situ on the surface of Y2O3 based on the fluorination mechanism. The composition and microstructure of the modified Y2O3 surface was thoroughly characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD analysis revealed the formation of distinct intermediate ammonium yttrium fluoride phases depending upon the heat treatment temperature (150 − 500 °C) through the fluorination of Y2O3 with NH4F. A stable YOF phase was formed ultimately at 300 °C. Plasma etching tests were performed using a mixture of CF4/Ar/O2 gases for 1 h. The microstructures of specimens are observed by SEM before and after plasma treatments. Plasma exposure tests demonstrated that specimens heat-treated at 500 °C for 2 h exhibit excellent plasma-resistance behavior with minimal surface damage, which is attributed to the presence of stable and dense YOF phase.

Mesoporous silica-based amorphous solid dispersions to enhance the oral bioavailability of Neratinib maleate

Neratinib maleate (NM) used in the treatment of breast cancer, has a low and variable oral bioavailability due to its pH-dependent solubility and gut-wall metabolism-restricted permeability. Mesoporous silica based solid dispersion of NM (SD-NM-MSi) was designed to improve its solubility and dissolution rate. SYLOID XDP 3050 was selected as a mesoporous silica carrier based on its higher drug loading (15.7 %) and good flow properties. The extensive surface area of the Mesoporous silica offered a suitable site for drug adsorption. Thermal and diffractometry analysis indicated that NM was adsorbed in an amorphous form. In vitro dissolution studies revealed that the optimized SD-NM-MSi showed a higher rate and extent of drug dissolution compared to plain NM in pH 3.0, pH 4.5, and 6.8, respectively. Similarly, an oral pharmacokinetic study (10 mg/kg) resulted in significantly higher plasma exposure for SD-NM-MSi compared to plain NM, with a 73 % (P < 0.01) increase in the relative oral bioavailability of NM.