Pharmacokinetic profiling of ZCL-278, a cdc42 inhibitor, and its effectiveness against chronic kidney disease.

ZCL-278 is a selective small molecule specifically inhibiting the Cdc42-intersectin interaction, yet its in-vivo pharmacokinetic and pharmacodynamic properties against renal diseases had not been determined. Thus, our study explored the absorption, distribution and excretion of ZCL-278 as well as its pharmacological efficacy against chronic kidney disease (CKD). With the optimized detection method, absolute oral bioavailability of ZCL-278 was determined as 10.99 % in male and 17.34 % in female rats. ZCL-278 was rapidly and abundantly distributed in various tissues, especially the kidney and heart, while few excreted through urine and feces. In the adenine-induced CKD mice, the increased plasma creatinine and urea, the decreased body weight as well as the renal pathological alterations, including vacuolization of renal tubular epithelial cells, granular degeneration, cell flattening, luminal dilation, and cylindruria, were significantly ameliorated after ZCL-278 administration. Moreover, ZCL-278 could also reverse the increased intensities of renal inflammation and fibrosis in the CKD mice. These results clarified the pharmacokinetics of ZCL-278 in rats and preliminarily indicated that ZCL-278 has favorable pharmacodynamic properties for CKD primed for lead development and optimization, warranting further drug development.

Pharmacokinetic study of Strongylocentrotus nudus egg polysaccharide in rats and beagles using a 3H-labeling method.

Strongylocentrotus nudus egg polysaccharide (SEP) extracted from sea urchins has potential anticancer activity. However, little is known about its pharmacokinetic properties. To investigate the pharmacokinetics of SEP, it was radiolabeled with tritium. Furthermore, a sensitive, selective, and rapid liquid scintillation counter (LSC) method for quantifying 3H-SEP in biological matrix was validated. The lower quantification limit of the method was 4 Bq. The relative standard deviations (RSDs) of the intra- and inter-day precision were <3.0% and <3.9%, respectively. 3H-SEP was successfully applied to investigate the pharmacokinetics of SEP after intravenous administration of 20, 40, and 80 mg/kg (40 µCi/kg) in rats and 5, 10, and 20 mg/kg (6 µCi/kg) in beagles. The AUC(0-t) of SEP at three different doses was 487.81 ± 39.99 mg/L*h, 1,003.10 ± 95.94 mg/L*h, and 2,188.84 ± 137.73 mg/L*h in rats and 144.12 ± 3.78 mg/L*h, 322.62 ± 28.03 mg/L*h, and 754.17 ± 37.79 mg/L*h in beagles. The terminal elimination half-life (t1/2) of SEP was longer in beagles (204.29 ± 139.34 h) than in rats (35.48 ± 6.04 h). The concentration of SEP in plasma declined rapidly in both rats and beagles. All the study results provide detailed pharmacokinetic profiles of SEP in two kinds of animals, which will be helpful for further development.

Effects of Grinding Parameters on the Processing Temperature, Crack Propagation and Residual Stress in Silicon Nitride Ceramics.

The surface/subsurface damage of engineering ceramics after machining has a great influence on the service performance of parts. In order to obtain a high grinding surface quality of engineering ceramics, and take silicon nitride ceramic as a research object, a series of grinding experiments were carried out. The effects of grinding parameters on longitudinal crack propagation depth and the surface residual stress of silicon nitride ceramics were analyzed by grinding experiments, and the residual stress at the location of crack propagation was obtained. The variation in the grinding temperature under different grinding parameters was explored. The influences of the grinding temperature on crack propagation depth and surface residual stress were clarified, the distribution of residual stress along the depth direction was discussed, and the relationship between the residual stress and crack propagation was revealed. The results show that the residual compressive stress on the surface of silicon nitride ceramics decreases with the increase in the depth of crack propagation and the degree of surface brittle spalling. The residual stress at the location of the crack propagation was residual tensile stress. The crack propagation depth increased with the increase in the residual tensile stress. The research provides a reference for the realization of high-quality surfaces in the grinding of silicon nitride ceramics.

Isomeric Oligo(Phenylenevinylene)-Based Covalent Organic Frameworks with Different Orientation of Imine Bonds and Distinct Photocatalytic Activities.

Imine-linked covalent organic frameworks (COFs) have been extensively studied in photocatalysis because of their easy synthesis and excellent crystallinity. The effect of imine-bond orientation on the photocatalytic properties of COFs, however, is still rarely studied. Herein, we report two novel COFs with different orientations of imine bonds using oligo(phenylenevinylene) moieties. The COFs showed similar structures but great differences in their photoelectric properties. COF-932 demonstrated a superior hydrogen evolution performance compared to COF-923 when triethanolamine was used as the sacrificial agent. Interestingly, the use of ascorbic acid led to the protonation of the COFs, further altering the direction of electron transfer. The photocatalytic performances were increased to 23.4 and 0.73 mmol g-1 h-1 for protonated COF-923 and COF-932, respectively. This study provides a clear strategy for the design of imine-linked COF-based photocatalysts and advances the development of COFs.

Evaluation of a Clinically Relevant Drug-Drug Interaction Between Rosuvastatin and Clopidogrel and the Risk of Hepatotoxicity.

Purpose: The combination therapy of rosuvastatin (RSV) and the platelet inhibitor clopidogrel (CP) is widely accepted in the management of cardiovascular diseases. The objective of the present study was to identify the mechanism of RSV-CP DDI and evaluate the risk of hepatotoxicity associated with the concomitant use of CP. Methods: We first studied the effect of CP and its major circulating metabolite, carboxylic acid metabolite (CPC), on RSV transport by overexpressing cells and membrane vesicles. Second, we investigated whether a rat model could replicate this DDI and then be used to conduct mechanistic studies and assess the risk of hepatotoxicity. Then, cytotoxicity assay in hepatocytes, biochemical examination, and histopathology were performed to measure the magnitude of liver injury in the presence and absence of DDI. Results: CP inhibited OATP1B1-mediated transport of RSV with an IC50 value of 27.39 µM. CP and CPC inhibited BCRP-mediated RSV transport with IC50 values of <0.001 and 5.96 µM, respectively. The CP cocktail (0.001 µM CP plus 2 µM CPC) significantly inhibited BCRP-mediated transport of RSV by 26.28%. Multiple p.o. doses of CP significantly increased intravenous RSV plasma AUC0-infinity by 76.29% and decreased intravenous RSV CL by 42.62%. Similarly, multiple p.o. doses of CP significantly increased p.o. RSV plasma AUC0-infinity by 87.48% and decreased p.o. RSV CL by 43.27%. CP had no effect on cell viability, while RSV exhibited dose-dependent cytotoxicity after 96 h incubation. Co-incubation of 100 µM CP and RSV for 96 h significantly increased intracellular concentrations and cell-to-medium concentration ratios of RSV and reduced hepatocyte viability. Histological evaluation of liver specimens showed patterns of drug-induced liver injury. Cholestasis was found in rats in the presence of DDI. Conclusion: CP is not a clinically relevant inhibitor for OATP1B1 and OATP1B3. The primary mechanism of RSV-CP DDI can be attributed to the inhibition of intestinal BCRP by CP combined with the inhibition of hepatic BCRP by CPC. The latter is likely to be more clinically relevant and be a contributing factor for increased hepatotoxicity in the presence of DDI.

Interactions between Oroxylin A with the solute carrier transporters and ATP-binding cassette transporters: Drug transporters profile for this flavonoid.

Oroxylin A is a flavonoid monomer extracted from Scutellaria baicalensis Georgi with neuroprotective, anti-tumor activity and many other biological functions. However, the interaction between Oroxylin A and the drug transporters has not been clearly reported. The purpose of this study is to investigate the interaction between Oroxylin A and the solute carrier transporters (OATP1B1, OATP1B3, OAT1, OAT3, OCT2, MATE1, and MATE2K), and ATP-binding cassette transporters (BCRP, MDR1). The HEK293 cell lines (HEK293-OATP1B1, HEK293-OATP1B3, HEK293-OAT1, HEK293-OAT3, HEK293-OCT2, HEK293-MATE1, and HEK293-MATE2K) that stably expressing previous listed human-derived transporters were employed to evaluate the solute carrier transporters. Vesicles expressing human BCRP and MDR1 transporters was employed to research ATP-binding cassette transporters. Our work suggested that Oroxylin A was a substrate of OATP1B1, OATP1B3, but not a substrate of the other transporters in the concentration range of our study. Oroxylin A shows concentration-dependent inhibition of OATP1B1, OAT1, OAT3 and BCRP transportation with the half-inhibitory concentration (IC50) of 7.03, 0.961, 0.112 µM, and 0.477 µM, respectively. No inhibitory effects on the transport activities of other transporters were observed for Oroxylin A. Drug transporters profile of Oroxylin A was first confirmed by our work, which provides important information for its pharmacokinetics, pharmacodynamics, and drug-drug interactions studies.

Development of a sensitive UPLC-MS/MS assay for domperidone and pharmacokinetics of domperidone tablet formulations in fasting and fed Chinese healthy subjects
.

OBJECTIVE: The objective of this study was to evaluate and compare the pharmacokinetics of domperidone tablets in Chinese healthy subjects both under fasting and fed conditions. MATERIALS AND METHODS: A total of 36 subjects were recruited to the monocentric pharmacokinetic study. All subjects were randomly divided into two groups. One group was given a single 10-mg oral dose of domperidone tablet after ~ 10 hours of fasting, and the other group was given the same oral dose of domperidone tablet 30 minutes after a high-fat meal. 18 blood samples were collected over 24 hours for every subject. Plasma concentrations of domperidone were analyzed by a rapid and sensitive UPLC-MS/MS assay, and the pharmacokinetic parameters were determined by the standard non-compartmental method. RESULTS: A significant difference was observed in the pharmacokinetics of domperidone between fasting and fed subjects. The AUC0-24h (area under curve of plasma concentration until the last concentration observed) was 75.71 h×µg/L in the fed subjects, which was much higher than AUC0-24h (56.76 h×µg/L) in the fasting subjects. For the fasting test, the T1/2 (elimination half-life) was 7.15 hours, Cmax (the maximum plasma concentration) was 16.97 µg/L, and tmax; was 0.79 hours. For the fed test, the T1/2 was 8.72 hours, Cmax was 15.11 µg/L, and tmax was 1.66 hours. T1/2 and tmax were both prolonged under fed condition when comparing fed condition to fasting condition. CONCLUSION: In this study, the absorption and elimination of domperidone was slowed down by a high-fat meal, with the mean tmax being 52% longer and T1/2 18% longer in fed subjects than in fasting subjects. In addition, a high-fat meal increased the exposure of domperidone, with the mean AUC being 25% more in fed subjects than in fasting subjects, which provided an important reference for the clinical application of domperidone in the Chinese population.

Effects of the ABCB1 and ABCG2 polymorphisms on the pharmacokinetics of afatinib in healthy Chinese volunteers.

1. Afatinib is an oral, selective tyrosine kinase inhibitor (TKI) primarily transported by P-glycoprotein (MDR1, gene code ABCB1) and breast cancer resistance protein (BCRP, gene code ABCG2). In the present study, the effects of ABCB1 and ABCG2 genetic polymorphisms on the pharmacokinetics of afatinib in healthy Chinese were investigated.2. Blood samples from 24 healthy participants who received afatinib were used for genotyping ABCB1 (1236C>T, 2677G > T/A, 3435C>T) and ABCG2 (34G>A, 421C>A) polymorphisms. Subsequently, the association between afatinib plasma concentrations and target single-nucleotide polymorphisms (SNPs) was analyzed.3. Among the five polymorphisms, plasma concentrations of afatinib in healthy subjects with ABCB1 1236CC-3435CC were remarkably higher than in other genotype subjects. No significant differences of afatinib exposure were found between the ABCG2 wild-type and heterozygous groups.4. The ABCB1 genetic polymorphism influenced the plasma exposure of afatinib, and gene testing before drug administration may be useful for clinically individualized use of afatinib. Our data suggest the usefulness of afatinib pharmacogenetics in treatment optimization.

A validated UPLC-MS/MS method for determination of tebipenem in human plasma and its application to a pharmacokinetic study in healthy volunteers.

A rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for determining tebipenem (TBPM) in human plasma. Plasma samples were prepared following a single-step protein precipitation method using acetonitrile and 3-morpholinopropanesulfonic acid (MOPS, pH 7.0, 50 mM) which equal volume of plasma samples were added for stabilizing the analyte. Separation was achieved using an ACQUITY UPLC BEH C18 (1.7 µm, 2.1 × 50 mm) column. A repeated gradient program was employed for reducing the carryover effect, and the total chromatographic run time was 3.0 min. Method validation results showed TBPM was linear in its analytical range i.e. between 0.1-20 µg/mL (r2>0.99), and the lower limit of quantification (LLOQ) was 0.1 µg/mL. The intra-run and inter-run precision (coefficient of variation, CV) was within 3.81%, and the accuracy (relative error, RE) was within ± 8.56%. The carryover was restricted below 8.1%. Matrix effects were minimal, and recovery of TBPM was 90.19-95.74%. The stability of TBPM in plasma sample stored at room temperature (25 °C) for 4 h, at -20 °C for 3 days, at -80 °C for 30 days, five freeze-thaw cycles at -80 °C and processed samples at auto sampler vials (8 °C) for 24 h were within 91.11-106.33%. Finally, the validated method was successfully applied to a pharmacokinetic study of TBPM in healthy volunteers after oral administration of tebipenem pivoxil (TBPM-PI).

Systemic Evaluation on the Pharmacokinetics of Platinum-Based Anticancer Drugs From Animal to Cell Level: Based on Total Platinum and Intact Drugs.

Cisplatin, carboplatin, and oxaliplatin are the common platinum-based anticancer drugs widely used in the chemotherapeutic treatment of solid tumors in clinic. However, the comprehensive pharmacokinetics of platinum-based anticancer drugs has not been fully understood yet. This leads to many limitations for the further studies on their pharmacology and toxicology. In this study, we conduct a systemic evaluation on the pharmacokinetics of three platinum analogues at animal and cell levels, with quantification of both total platinum and intact drugs. A detailed animal study to address and compare the different pharmacokinetic behaviors of three platinum analogues has been conducted in three biological matrices: blood, plasma, and ultrafiltrate plasma. Carboplatin showed an obviously different pharmacokinetic characteristic from cisplatin and oxaliplatin. On the one hand, carboplatin has the highest proportion of Pt distribution in ultrafiltrate plasma. On the other hand, carboplatin has the highest intact drug exposure and longest intact drug elimination time in blood, plasma, and ultrafiltrate plasma, which may explain its high hematotoxicity. Additionally, the cellular and subcellular pharmacokinetics of oxaliplatin in two colon cancer HCT-116/LOVO cell lines has been elucidated for the first time. The biotransformation of intact oxaliplatin in cells was rapid with a fast elimination, however, the generated platinum-containing metabolites still exist within cells. The distribution of total platinum in the cytosol is higher than in the mitochondria, followed by the nucleus. Enrichment of platinum in mitochondria may affect the respiratory chain or energy metabolism, and further lead to cell apoptosis, which may indicate mitochondria as another potential target for efficacy and toxicity of oxaliplatin.

Quantification of triacontanol and its PEGylated prodrug in rat plasma by GC-MS/MS: Application to a pre-clinical pharmacokinetic study.

PEGylation techniques have been increasingly employed in drug delivery system and chemical modification of compounds with low aqueous solubility. Triacontanol (TA) is a natural product with several pharmacological activities, but its low aqueous solubility significantly limited its application. PEGylated triacontanol (PEG-TA) was designed as the prodrug to improve the aqueous solubility and pharmacokinetic properties of TA. On the basis of salting-out assisted liquid-liquid extraction (SALLE) and saponification sample preparation procedure, a reliable gas chromatography tandem mass spectrometric (GC-MS/MS) method was developed and validated for the quantification of PEG-TA and its metabolite TA in rat plasma after separation and transformation. Acetonitrile-methanol (9:1, v/v) and ammonium acetate (10 M) were utilized to separate PEG-TA and TA (including conjugated TA with fatty acid). Saponification facilitated the complete conversion of PEG-TA into TA, so PEG-TA could be indirectly quantified. The results revealed that the GC-MS/MS method had excellent selectivity, accuracy and linearity. Calibration curves were linear (R2>0.99) within the range of 20.0-1000.0 ng/mL for TA and 100.0-10,000.0 ng/mL for PEG-TA. The intra- and inter-day precision of quality control samples were within 15%, and their accuracy values varied from 93.54% to 113.38%. This analytical method has been successfully applied to pharmacokinetic study of PEG-TA. This study can facilitate the further exploration and quantification of PEGylated prodrugs.

Hydrophilic interaction liquid chromatography-tandem mass spectrometry method for the determination of intact oxaliplatin in cells: validated and applied in colon cancer HCT-116 cell line.

Oxaliplatin is a platinum compound that is frequently prescribed for the chemotherapeutic treatment of colorectal cancer. In tumor cells, cellular uptake is the first step of oxaliplatin action. Cellular accumulation of oxaliplatin is considered to play an important role in anti-cancer efficacy. However, limited information about cellular accumulation of intact oxaliplatin is available. In this study, a sensitive hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) approach for the quantification of oxaliplatin in cells was developed and validated. The method allowed for a rapid and simple determination of intact oxaliplatin in cell lysate. The retention time of oxaliplatin was 3.04 min, which was achieved by applying a chromatographic gradient elution of 5 min. The lower limit of quantification (LLOQ) was 2 ng/mL and the analytical range of oxaliplatin was linear between 2-200 ng/mL. The intra-day precision and inter-day precision (RSD (relative standard deviation)) ranged from 0.52 to 7.89%, and the accuracy (RE (relative error)) was within ±â€¯4.5%. Matrix effects and recovery were acceptable. The method was successfully used for the determination of intact oxaliplatin uptake by HCT-116 colon cancer cells. Thus, our findings may prospectively support a celluar pharmacokinetic study and low concentration measurement of intact oxaliplatin in the clinic.

A simple LC-MS/MS method facilitated by salting-out assisted liquid-liquid extraction to simultaneously determine trans-resveratrol and its glucuronide and sulfate conjugates in rat plasma and its application to pharmacokinetic assay.

A simple LC-MS/MS method facilitated by salting-out assisted liquid-liquid extraction (SALLE) was applied to simultaneously investigate the pharmacokinetics of trans-resveratrol (Res) and its major glucuronide and sulfate conjugates in rat plasma. Acetonitrile-methanol (80:20, v/v) and ammonium acetate (10 mol L-1 ) were used as extractant and salting-out reagent to locate the target analytes in the supernatant after the aqueous and organic phase stratification, then the analytes were determined via gradient elution by LC-MS/MS in negative mode in a single run. The analytical method was validated with good selectivity, acceptable accuracy (>85%) and low variation of precision (<15%). SALLE showed better extraction efficiency of target glucuronide and sulfate conjugates (>80%). The method was successfully applied to determine Res and its four conjugated metabolites in rat after Res administration (intragastric, 50 mg kg-1 ; intravenous, 10 mg kg-1 ). The systemic exposures to Res conjugates were much higher than those to Res (AUC0-t , i.v., 7.43 µm h; p.o., 8.31 µm h); Res-3-O-ß-d-glucuronide was the major metabolite (AUC0-t , i.v., 66.1 µm h; p.o., 333.4 µm h). The bioavailability of Res was estimated to be ~22.4%. The reproducible SALLE method simplified the sample preparation, drastically improved the accuracy of the concomitant assay and gave full consideration of extraction recovery to each target analyte in bio-samples.

An outbreak of type π vaccine-derived poliovirus in Sichuan province, China: emergence and circulation in an under-immunized population.

BACKGROUND: During August 2011-February 2012, an outbreak of type Π circulating vaccine-derived poliovirus (cVDPVs) occurred in Sichuan Province, China. METHODS: A field investigation of the outbreak was conducted to characterize outbreak isolates and to guide emergency response. Sequence analysis of poliovirus capsid protein VP1 was performed to determine the viral propagation, and a coverage survey was carried out for risk assessment. RESULTS: One clinical compatible polio case and three VDPV cases were determined in Ngawa County, Ngawa Tibetan and Qiang Autonomous Prefecture, Sichuan Province. Case patients were unimmunized children, 0.8-1 years old. Genetic sequencing showed that the isolates diverged from the VP1 region of the type Π Sabin strain by 5-12 nucleotides (nt) and shared the same 5 nt VP1 substitutions, which indicate single lineage of cVDPVs. Of the 7 acute flaccid paralysis cases (all>6 months) reported in Ngawa Prefecture in 2011, 4 (57.1%) cases (including 2 polio cases) did not receive oral attenuated poliovirus vaccine. Supplementary immunization activities (SIAs) were conducted in February-May, 2012, and the strain has not been isolated since. CONCLUSION: High coverage of routine immunization should be maintained among children until WPV transmission is globally eradicated. Risk assessments should be conducted regularly to pinpoint high risk areas or subpopulations, with SIAs developed if necessary.

[A seroepidemiologic analysis of hepatitis B in Sichuan province].

OBJECTIVE: To understand the changes of hepatitis B infection rates, before and after the hepatitis B vaccine was included into EPI, and to evaluate the effect of immunization which would lead to the development of a more appropriate hepatitis B control strategy. METHODS: Seroepidemiologic method, with multi-section random sampling method were chosen. 14 sites from 8 counties were involved. 2-4 ml of the vein blood was drawn from all the individuals engaged in the study including 3806 samples. HBsAg, anti-HBs, anti-HBc of the samples were tested with ELISA. RESULTS: Standardized positive rates of HBsAg and HBsAb were found as 7.05% and 29.77% respectively with the overall infection rate of HBV as 40.30%. The hepatitis B vaccine coverage of the children under 15 years was 70.73% and the positive rates for both HBsAg and anti-HBs were 2.62% and 56.68%, respectively. The coverage of hepatitis B vaccine among children under 3 years was 83.44% and the positive rates of both HBsAg and anti-HBs were 1.47% and 67.69% respectively, hepatitis B vaccine coverage of children under 3 years was 85.77%, with positive rates of HBsAg and anti-HBs as 1.78% and 75.44% respectively. CONCLUSION: Results from our study revealed that since the introduction of hepatitis B vaccination, the prevalence rates of HBsAg and HBV infection had an obvious decline, especially in children aged under 15 years of old, suggesting that some changes had occurred in the epidemic characteristics of hepatitis B in Sichuan.