Structure-Based Analysis of Cefaclor Pharmacokinetic Diversity According to Human Peptide Transporter-1 Genetic Polymorphism.

Cefaclor is a substrate of human-peptide-transporter-1 (PEPT1), and the impact of inter-individual pharmacokinetic variation due to genetic polymorphisms of solute-carrier-family-15-member-1 (SLC15A1) has been a topic of great debate. The main objective of this study was to analyze and interpret cefaclor pharmacokinetic variations according to genetic polymorphisms in SLC15A1 exons 5 and 16. The previous cefaclor bioequivalence results were integrated with additional SLC15A1 exons 5 and 16 genotyping results. An analysis of the structure-based functional impact of SLC15A1 exons 5 and 16 genetic polymorphisms was recently performed using a PEPT1 molecular modeling approach. In cefaclor pharmacokinetic analysis results according to SLC15A1 exons 5 and 16 genetic polymorphisms, no significant differences were identified between genotype groups. Furthermore, in the population pharmacokinetic modeling, genetic polymorphisms in SLC15A1 exons 5 and 16 were not established as effective covariates. PEPT1 molecular modeling results also confirmed that SLC15A1 exons 5 and 16 genetic polymorphisms did not have a significant effect on substrate interaction with cefaclor and did not have a major effect in terms of structural stability. This was determined by comprehensively considering the insignificant change in energy values related to cefaclor docking due to point mutations in SLC15A1 exons 5 and 16, the structural change in conformations confirmed to be less than 0.05 Å, and the relative stabilization of molecular dynamic simulation energy values. As a result, molecular structure-based analysis recently suggested that SLC15A1 exons 5 and 16 genetic polymorphisms of PEPT1 were limited to being the main focus in interpreting the pharmacokinetic diversity of cefaclor.

Human risk assessment of 4-n-nonylphenol (4-n-NP) using physiologically based pharmacokinetic (PBPK) modeling: analysis of gender exposure differences and application to exposure analysis related to large exposure variability in population.

As a toxic substance, 4-n-nonylphenol (4-n-NP) or 4-nonylphenol (4-NP) is widely present in the environment. 4-n-NP is a single substance with a linear-alkyl side chain, but 4-NP usually refers to a random mixture containing various branched types. Unfortunately, human risk assessment and/or exposure level analysis for 4-n-NP (or 4-NP) were almost nonexistent, and related research was urgently needed. This study aimed to analyze the various exposures of 4-n-NP (or 4-NP) through development of a physiologically based-pharmacokinetic (PBPK) model considering gender difference in pharmacokinetics of 4-n-NP and its application to human risk assessment studies. A PBPK model was newly developed considering gender differences in 4-n-NP pharmacokinetics and applied to a human risk assessment for each gender. Exposure analysis was performed using a PBPK model that considered gender differences in 4-n-NP (or 4-NP) exposure and high variabilities in several countries. Furthermore, an extended application was attempted as a human risk assessment for random mixture 4-NP, which is difficult to accurately evaluate in reality. External-exposure and margin-of-safety estimated with the same internal exposure amount differed between genders, meaning the need for a differentiated risk assessment considering gender. Exposure analysis based on biomonitoring data confirmed large variability in exposure to 4-n-NP (or 4-NP) by country, group, and period. External-exposures estimated using PBPK model varied widely, ranging from 0.039 to 63.875 mg/kg/day (for 4-n-NP or 4-NP). By country, 4-n-NP (or 4-NP) exposure was higher in females than in males and the margin-of-safety tended to be low. Overall, exposure to 4-n-NP (or 4-NP) in populations was largely not safe, suggesting need for ongoing management and monitoring. Considering low in vivo accumulation confirmed by PBPK model, risk reduction of 4-n-NP is possible by reducing its use.

Air-Coupled Ultrasound Sealing Integrity Inspection Using Leaky Lamb Waves in a Simplified Model of a Lithium-Ion Pouch Battery: Feasibility Study.

Inspecting the sealing integrity of lead tabs is an important means of ensuring the reliability and safety of pouch-type lithium-ion (Li-ion) batteries with a thin multi-layered aluminum (Al) laminated film. This paper presents a new air-coupled ultrasonic non-destructive testing (NDT) inspection method based on leaky Lamb wave transmission; and reception for evaluating the sealing integrity between the lead tab and the Al pouch film. The proposed method uses the critical incidence angle between the air and the layer with the fastest Lamb wave velocity to maximize the signal-to-noise ratio in the through-transmission mode. To determine the critical incidence angle, phantom experiments with two test pieces (i.e., an Al tab and an Al tab sealed with an Al pouch film) are conducted. In addition, 2D scans are performed at various incidence angles for an inhouse pouch-type Li-ion battery with a 1-mm-wide foreign material inserted as a defect. At the critical incidence angle (i.e., 22°), the proposed air-coupled ultrasonic NDT method in through-transmission mode successfully identifies the shape and location of the defect through c-scan image reconstruction. These preliminary results indicate that the proposed air-coupled ultrasonic NDT method with leaky Lamb waves can be used to inspect the sealing integrity of Li-ion pouch batteries in dry test conditions.

Human risk assessment of di-isobutyl phthalate through the application of a developed physiologically based pharmacokinetic model of di-isobutyl phthalate and its major metabolite mono-isobutyl phthalate.

Di-isobutyl phthalate (DiBP) is a substance used in the production of objects frequently used in human life. Mono-isobutyl phthalate (MiBP), a major in vivo metabolite of DiBP, is a biomarker for DiBP exposure assessment. Therefore, risk assessment studies on DiBP and MiBP, which have not yet been reported in detail, are needed. The aim of this study was to develop and evaluate a physiologically based pharmacokinetic (PBPK) model for DiBP and MiBP in rats and extend this to human risk assessment based on human exposure. Pharmacokinetic studies were performed in male rats following the administration of 5-100 mg/kg DiBP, and these results were used for the development and validation of the PBPK model. In addition, the previous pharmacokinetic results in female rats following DiBP administration and the pharmacokinetic results in both males and females according to multiple exposures to DiBP were used to develop and validate the PBPK model. The metabolism of DiBP to MiBP in the body was very significant and rapid, and the biodistribution of MiBP was broad and major. Furthermore, the amount of MiBP in the body showed a correlation with DiBP exposure, and from this, a PBPK model was developed to evaluate the external exposure of DiBP from the internal exposure of MiBP. The predicted rat plasma, urine, fecal, and tissue concentrations using the developed PBPK model fitted well with the observed values. The established PBPK model for rats was extrapolated to a human PBPK model of DiBP and MiBP based on human physiological parameters and allometric scaling. The reference dose of 0.512 mg/kg/day of DiBP and external doses of 6.14-280.90 µg/kg/day DiBP for human risk assessment were estimated using Korean biomonitoring values. Valuable insight and approaches to assessing human health risks associated with DiBP exposure were provided by this study.

Toxicokinetics of di-isodecyl phthalate and its major metabolites in rats through the application of a developed and validated UHPLC-ESI-MS/MS method.

Di-isodecyl phthalate (DiDP) is a high-molecular-weight phthalate that is mainly used as a plasticizer for plastics. Therefore, exposure to DiDP in the environment has become common with the increasing use of plastics around the world. Environmental regulations and scientific risk management for DiDP, which can be associated with endocrine disruption and various metabolic diseases, are urgently needed. The purpose of this study was to provide useful reference material for future human DiDP risk assessments by conducting toxicokinetic studies on DiDP. Rats were given 100 mg/kg of DiDP orally or intravenously, and plasma, urine, feces, and various tissues were sampled at preset times. DiDP and its major metabolites mono-isodecyl-phthalate (MiDP), mono-hydroxy-isodecyl-phthalate (MHiDP), mono-carboxy-isononyl-phthalate (MCiNP), and mono-oxo-isodecyl-phthalate (MOiDP) were simultaneously quantified from collected biological samples through the application of a newly developed and verified ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometer (UHPLC-ESI-MS/MS) method. Based on the quantitative results for each analyte, toxicokinetic analyses were performed. DiDP was rapidly and extensively metabolized to MiDP, MHiDP, MCiNP, and MOiDP. The major metabolite excreted in the urine was MCiNP, suggesting that it could be a useful biomarker. The conjugated forms of DiDP and its metabolites have been significantly quantified in the plasma, urine, and feces. DiDP and its major metabolites were also distributed in various tissues in significant quantities. The toxicokinetic properties of DiDP, which have not been clearly reported previously, were identified through this study. This report will serve as a useful reference for future DiDP environmental regulation and scientific human risk assessment studies.

Simultaneous determination of asarinin, ß-eudesmol, and wogonin in rats using ultraperformance liquid chromatography-tandem mass spectrometry and its application to pharmacokinetic studies following administration of standards and Gumiganghwal-tang.

Asarinin, ß-eudesmol, and wogonin have common antiangiogenic activities and have the potential for use in chemotherapy. Besides, they are multivalent substances that are combined in various herbal medicines. The purpose of this study was to develop a method for simultaneous analysis of asarinin, ß-eudesmol, and wogonin, which are representative pharmacological components of Asarum heterotropoides, Atractylodes lancea, and Scutellaria baicalensis, respectively, in rat biosamples using ultraperformance liquid chromatography-tandem mass spectrometry. The three components were separated using 5 mm aqueous ammonium acetate containing 0.1% formic acid and acetonitrile as a mobile phase, equipped with a KINETEX core-shell C18 column. The analysis was quantitated on a triple-quadrupole mass-spectrometer employing electrospray ionization, and operated in the multiple reaction monitoring mode. The chromatograms showed high resolution, sensitivity, and selectivity with no interference with plasma, urine, and feces constituents. The developed analytical method satisfied international guidance criteria and could be successfully applied to the pharmacokinetic (PK) studies evaluating oral bioavailability of asarinin, ß-eudesmol, and wogonin after oral and intravenous administration and their urinary and fecal excretion ratios after oral administration to rats. Furthermore, the analysis was extended to PK studies following oral administration of Gumiganghwal-tang. This study was the first simultaneous analysis of the aforesaid three constituents in rat plasma, urine, and feces that also determined their PK parameters.

Transrectal Ultrasound and Photoacoustic Imaging Probe for Diagnosis of Prostate Cancer.

A combined transrectal ultrasound and photoacoustic (TRUS-PA) imaging probe was developed for the clear visualization of morphological changes and microvasculature distribution in the prostate, as this is required for accurate diagnosis and biopsy. The probe consisted of a miniaturized 128-element 7 MHz convex array transducer with 134.5° field-of-view (FOV), a bifurcated optical fiber bundle, and two optical lenses. The design goal was to make the size of the TRUS-PA probe similar to that of general TRUS probes (i.e., about 20 mm), for the convenience of the patients. New flexible printed circuit board (FPCB), acoustic structure, and optical lens were developed to meet the requirement of the probe size, as well as to realize a high-performance TRUS-PA probe. In visual assessment, the PA signals obtained with the optical lens were 2.98 times higher than those without the lens. Moreover, the in vivo experiment with the xenograft BALB/c (Albino, Immunodeficient Inbred Strain) mouse model showed that TRUS-PA probe was able to acquire the entire PA image of the mouse tight behind the porcine intestine about 25 mm depth. From the ex vivo and in vivo experimental results, it can be concluded that the developed TRUS-PA probe is capable of improving PA image quality, even though the TRUS-PA probe has a cross-section size and an FOV comparable to those of general TRUS probes.

Mechanical and Pharmacological Revascularization Strategies for Prevention of Microvascular Dysfunction in ST-Segment Elevation Myocardial Infarction: Analysis from Index of Microcirculatory Resistance Registry Data.

OBJECTIVES: We aimed to identify mechanical and pharmacological revascularization strategies correlated with the index of microcirculatory resistance (IMR) in ST-elevation myocardial infarction (STEMI) patients. BACKGROUND: Microvascular dysfunction (MVD) after STEMI is correlated with infarct size and poor long-term prognosis, and the IMR is a useful analytical method for the quantitative assessment of MVD. However, therapeutic strategies that can reliably reduce MVD remain uncertain. METHODS: Patients with STEMI who underwent primary percutaneous coronary intervention (PCI) were enrolled. The IMR was measured with a pressure sensor/thermistor-tipped guidewire immediately after primary PCI. High IMR was defined as values ≥66th percentile of IMR in enrolled patients (IMR > 30.9 IU). RESULTS: A total of 160 STEMI patients were analyzed (high IMR = 54 patients). Clinical factors for Killip class (P=0.006), delayed hospitalization from symptom onset (P=0.004), peak troponin-I level (P=0.042), and multivessel disease (P=0.003) were associated with high IMR. Achieving final thrombolysis in myocardial infarction myocardial perfusion grade 3 tended to be associated with low IMR (P=0.119), whereas the presence of distal embolization was significantly associated with high IMR (P=0.034). In terms of therapeutic strategies that involved adjusting clinical and angiographic factors associated with IMR, preloading of third-generation P2Y12 inhibitors correlated with reducing IMR value (ß = -10.30, P < 0.001). Mechanical therapeutic strategies including stent diameter/length, preballoon dilatation, direct stenting, and thrombectomy were not associated with low IMR value (all P > 0.05), and postballoon dilatation was associated with high IMR (ß = 8.30, P=0.020). CONCLUSIONS: In our study, mechanical strategies were suboptimal in achieving myocardial salvage. Preloading of third-generation P2Y12 inhibitors revealed decreased IMR value, indicative of MVD prevention.

Splenic infarction and infectious diseases in Korea.

BACKGROUND: The spleen contains immune cells and exhibits a pattern of infarction different from other organs; as such, splenic infarction (SI) may provide important clues to infection. However, the nature of the relationship between SI and infectious disease(s) is not well understood. Accordingly, this retrospective study investigated the relationship between SI and infection. METHODS: Hospital records of patients with SI, who visited Inha University Hospital (Incheon, Republic of Korea) between January 2008 and December 2018, were reviewed. Patient data regarding clinical presentation, causative pathogens, risk factors, and radiological findings were collected and analyzed. RESULTS: Of 353 patients with SI, 101 with infectious conditions were enrolled in this study, and their data were analyzed to identify associations between SI and infection. Ten patients were diagnosed with infective endocarditis (IE), and 26 exhibited bacteremia without IE. Twenty-seven patients experienced systemic infection due to miscellaneous causes (negative result on conventional automated blood culture), including the following intracellular organisms: parasites (malaria [n = 12], babesiosis [n = 1]); bacteria (scrub typhus [n = 5]); viruses (Epstein-Barr [n = 1], cytomegalovirus [n = 1]); and unidentified pathogen[s] (n = 7). Splenomegaly was more common among patients with miscellaneous systemic infection; infarction involving other organs was rare. Thirty-eight patients had localized infections (e.g., respiratory, intra-abdominal, or skin and soft tissue infection), and most (35 of 38) had other risk factors for SI. CONCLUSIONS: In this study, various infectious conditions were found to be associated with SI, and intracellular organisms were the most common causative pathogens. Further studies are needed to examine other possible etiologies and the underlying pathophysiological mechanisms.

Impact of gender on heart failure presentation in non-obstructive hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a genetic cardiac disease that represents a broad spectrum of morphologic features and clinical presentations. However, little is known about the impact of gender differences in heart failure (HF) development in non-obstructive HCM. We assessed clinical and echocardiographic parameters according to gender in patients with non-obstructive HCM and evaluated the impact of gender on HF presentation and cardiovascular (CV) outcomes in this population. We investigated 202 consecutive patients with non-obstructive HCM. Clinical parameters and conventional echocardiographic measurements including tissue Doppler measurements were evaluated and compared according to gender. Additionally, left ventricular (LV) deformation was assessed with global longitudinal strain (GLS) utilizing 2D speckle tracking software. Of the 202 patients (age = 63 ± 14 years, male: female = 141: 61), 51 patients (24.8%) presented with HF and female patients had HF more frequently (52.5% vs. 12.8%, P < 0.001). Females were older, had a higher prevalence of atrial fibrillation, had increased left atrial volume (LAV), and a higher ratio of early diastolic mitral inflow to early annular velocity (E/e') than males (70 ± 12 years vs. 59 ± 14 years, P < 0.001 for age; 51.4 ± 19.3 mL/m2 vs. 40.0 [Formula: see text] 13.4 mL/m2, P < 0.001 for indexed LAV; 17.2 [Formula: see text] 6.0 vs. 13.0 [Formula: see text] 4.3, P < 0.001 for E/e'). While LV maximal thickness and LV ejection fraction were comparable between men and women, GLS was decreased significantly in female patients (- 13.5 [Formula: see text] 3.4% vs. - 15.6 [Formula: see text] 4.0%, P = 0.001 for GLS). Even after adjusting for clinical factors, female was independently associated with HF presentation (Odd ratio 5.19, 95% CI 2.24-12.03, P < 0.001). During a median follow-up duration 34.0 months, 20 patients (9.9%) had HF hospitalization or CV death. In a multivariable analysis, female gender was associated with higher risk of the composite of HF hospitalization or CV death and HF hospitalization alone than male (Adjusted hazard ratio [HR] = 3.31, 95% CI 1.17-9.35, P = 0.024 for primary composite outcome of HF hospitalization or CV death; adjusted HR = 4.78, 95% CI 1.53-14.96, P = 0.007 for HF hospitalization). In patients with non-obstructive HCM, female patients presented with HF more frequently and showed a higher risk of CV events than male patients. LA volume, E/e' and LV mechanics were different between the genders, suggesting that these might contribute to greater susceptibility to HF in women with HCM.

Simultaneous determination of three iridoid glycosides of Rehmannia glutinosa in rat biological samples using a validated hydrophilic interaction-UHPLC-MS/MS method in pharmacokinetic and in vitro studies.

The purpose of this study was to develop a method for simultaneous analysis of aucubin, catalpol, and geniposide, which are representative iridoid glycoside constituents of Rehmannia glutinosa, in rat plasma, urine, and feces using hydrophilic interaction ultra high-performance liquid chromatography with tandem mass spectrometry. The three components were separated using 10 mmol/L aqueous ammonium formate containing 0.01% (v/v) formic acid and acetonitrile as a mobile phase by gradient elution at a flow rate of 0.2 mL/min, equipped with a Kinetex® HILIC column (50 × 2.1 mm, 2.6 µm). Quantitation of this analysis was performed on a triple quadrupole mass spectrometer employing electrospray ionization and operated in multiple reaction monitoring mode. The chromatograms showed high resolution, sensitivity, and selectivity with no interference with plasma constituents. In all three iridoid glycosides, both the intra- and interbatch precisions (coefficient of variation %) were less than 4.81%. The accuracy was 96.56-103.55% for aucubin, 95.23-106.21% for catalpol, and 94.50-104.16% for geniposide. The developed analytical method satisfied the criteria of international guidance and was successfully applied to pharmacokinetic studies including oral bioavailability of aucubin, catalpol, and geniposide, and their urinary and fecal excretion ratios after oral or intravenous administration to rats. The new method was also applied to measure plasma protein binding ratios in vitro.

Risk assessment for humans using physiologically based pharmacokinetic model of diethyl phthalate and its major metabolite, monoethyl phthalate.

Diethyl phthalate (DEP) belongs to phthalates with short alkyl chains. It is a substance frequently used to make various products. Thus, humans are widely exposed to DEP from the surrounding environment such as food, soil, air, and water. As previously reported in many studies, DEP is an endocrine disruptor with reproductive toxicity. Monoethyl phthalate (MEP), a major metabolite of DEP in vivo, is a biomarker for DEP exposure assessment. It is also an endocrine disruptor with reproductive toxicity, similar to DEP. However, toxicokinetic studies on both MEP and DEP have not been reported in detail yet. Therefore, the objective of this study was to evaluate and develop physiologically based pharmacokinetic (PBPK) model for both DEP and MEP in rats and extend this to human risk assessment based on human exposure. This study was conducted in vivo after intravenous or oral administration of DEP into female (2 mg/kg dose) and male (0.1-10 mg/kg dose) rats. Biological samples consisted of urine, plasma, and 11 different tissues. These samples were analyzed using UPLC-ESI-MS/MS method. For DEP, the tissue to plasma partition coefficient was the highest in the kidney, followed by that in the liver. For MEP, the tissue to plasma partition coefficient was the highest in the liver. It was less than unity in all other tissues. Plasma, urine, and fecal samples were also obtained after IV administration of MEP (10 mg/kg dose) to male rats. All results were reflected in a model developed in this study, including in vivo conversion from DEP to MEP. Predicted concentrations of DEP and MEP in rat urine, plasma, and tissue samples using the developed PBPK model fitted well with observed values. We then extrapolated the PBPK model in rats to a human PBPK model of DEP and MEP based on human physiological parameters. Reference dose of 0.63 mg/kg/day (or 0.18 mg/kg/day) for DEP and external doses of 0.246 µg/kg/day (pregnant), 0.193 µg/kg/day (fetus), 1.005-1.253 µg/kg/day (adults), 0.356-0.376 µg/kg/day (adolescents), and 0.595-0.603 µg/kg/day (children) for DEP for human risk assessment were estimated using Korean biomonitoring values. Our study provides valuable insight into human health risk assessment regarding DEP exposure.

Simultaneous measurement of epinastine and its metabolite, 9,13b-dehydroepinastine, in human plasma by a newly developed ultra-performance liquid chromatography-tandem mass spectrometry and its application to pharmacokinetic studies.

Epinastine is an antiallergic drug with high selectivity for histamine receptors. It has been reported that 9,13b-dehydroepinastine is present as a metabolite in vivo in humans, but there was little information about their pharmacokinetics (PKs) in humans. Although several analytical methods have been reported for epinastine analysis in different matrices, none are available for its metabolite. Therefore, the purpose of this study was to develop an analytical method to simultaneously measure epinastine and its metabolite, 9,13b-dehydroepinastine, in human plasma samples using an ultra-performance liquid chromatography-tandem mass spectrometer. Analytes were separated on a C18 column. Quantification of this analysis was performed on a triple-quadrupole mass spectrometer. Chromatograms showed high sensitivity, selectivity, and resolution with no interference with plasma constituents. Calibration curves for both epinastine and 9,13b-dehydroepinastine in human plasma were 0.1-50 ng/ml and displayed excellent linearity with correlation coefficients (r2 ) >0.99. The developed analytical method satisfied the criteria of international guidance and was validated. The method could be successfully applied to pharmacokinetic studies of epinastine and, for the first time, the metabolite kinetics of epinastine to 9,13b-dehydroepinastine in humans after oral administration of 20 mg epinastine hydrochloride tablets. Our study is expected to be useful in future studies such as dosage settings and clinical pharmacotherapy.

Ivabradine-Induced Torsade de Pointes in Patients with Heart Failure Reduced Ejection Fraction.

Ivabradine is a selective inhibitor of the sinoatrial node "funny" current, prolonging the slow diastolic depolarization. As it has the ability to block the heart rate selectively, it is more effective at a faster heart rate. It is recommended for the treatment of heart failure reduced ejection fraction in the presence of beta-blocker therapy for the further reduction of the heart rate. However, previous reports have shown the association of Torsade de pointes (TdP) with concurrent use of ivabradine and drugs resulting in QT prolongation or blockage of the metabolic breakdown of ivabradine. In this article, we report two cases of patients with heart failure reduced ejection fraction who developed TdP after ivabradine use. Our report highlights the need to exercise caution with the administration of ivabradine in the presence of a reduced repolarization reserve, such as QT prolongation or metabolic insufficiency.

Pharmacokinetic Comparison of Epinastine Using Developed Human Plasma Assays.

The purpose of the study was to develop two new methods, HPLC-UV and UPLC-MS/MS, for quantifying epinastine in human plasma and to compare pharmacokinetic (PK) parameters obtained using them. Even in the same sample, there may be a difference in the quantitative value of drug depending on the assay, so that minor changes in PK parameter values may affect drug dose and usage settings. Therefore, selection and establishment of analytical methods are very important in PK studies of drugs, and a comparison of PK parameters according to analytical methods will be vital. For this study of PK parameter change, we newly developed two methods, HPLC-UV and UPLC-MS/MS, which are most commonly used to quantify epinastine concentrations in human plasma. All developed methods satisfied the international guidelines and criteria for successful application to PK study of 20 mg epinastine hydrochloride tablets after oral administration to twenty-six humans. A comparison of these two methods for in vivo analysis of epinastine was performed for the first time. This comparison study confirmed that different dose and usage settings might be possible based on PK parameters calculated using other analyses. Such changes in calculated PK parameters according to analytical methods would be crucial in the clinic.

Gender differences in pharmacokinetics and tissue distribution of 4-n-nonylphenol in rats.

The aim of this study was to newly identify and investigate the gender differences in pharmacokinetics (PKs) and tissue distribution of 4-n-nonylphenol (4-n-NP) in both male and female Sprague-Dawley rats. For this study, a UPLC-ESI-MS/MS system for 4-n-NP was developed as a sensitive and rapid analysis method and validated according to the accepted criteria of the international guidelines. The method was finally applied to the analysis of plasma, urine, feces, and nine different tissue samples of rats. PK parameters were calculated after single oral or intravenous administration of 4-n-NP at a dose of 10 or 50 mg/kg. Mean half-life of 4-n-NP in female rats was shorter and its clearance was larger for all doses than those in male rats. There were statistically significant differences in excretion patterns of urine and feces between male and female rats. Distribution of nine different tissues for 4-n-NP was greater in male than in female, and 4-n-NP was highly distributed in the liver or kidney. It was also specific that the distribution of 4-n-NP into brain was considerable. These results suggest that there are gender differences in the PKs of 4-n-NP in rats. Although, 4-n-NP is known to be a reproductive toxicant, reports on its PKs, excretion pattern, tissue distribution, and gender difference are limited. Therefore, our results will be useful data for gender differences as well as toxicokinetic information for 4-n-NP. In addition, it is expected to be very important for future risk assessment and PBPK model establishment of 4-n-NP.

Subchronic toxicity evaluation of ethanol extract of Cassia tora L. seeds in rats.

Cassia tora Linn. is an annual or perennial plant of the Fabaceae/Leguminosae family. It is used in traditional medicine for various biological activities including anti-constipation, anti-inflammatory, visual acuity, and hepato-protective activities. The present study was carried out to investigate the potential toxicity of C. tora L. seed ethanol extract (CTSEE) following a 13-week repeated oral administration to Sprague-Dawley rats. CTSEE was administered orally to male and female rats for 13 weeks at 0 (control), 500, 1000, and 2000 mg/kg/day (n = 10, for male and female rats for each dose). Additional recovery groups from the control group and high dose group were observed for a 4-week recovery period. At the end of the treatment and recovery periods, animals were sacrificed, and their organs were weighed and blood samples collected. There were no treatment-related adverse effects in clinical signs, body weight, food consumption, estrous cycle, sperm parameters, urinalysis, hematology, serum biochemistry, necropsy findings, organ weight, and histopathology at any doses tested. Under the present experimental conditions, the no-observed-adverse-effect level of the CTSEE was >2000 mg/kg/day in both genders, and no target organs were identified.

A novel and sensitive UPLC-MS/MS method to determine mequitazine in rat plasma and urine: Validation and its application to pharmacokinetic studies.

The aim of this study was to develop an analytical method to determine mequitazine in rat plasma and urine. Mequitazine was separated by UPLC-MS/MS equipped with a Kinetex core-shell C18 column (50 × 2.1 mm, 1.7 µm) using 0.1% (v/v) aqueous formic acid and acetonitrile containing 0.1% (v/v) formic acid as a mobile phase by gradient elution at a flow rate of 0.3 mL/min. Quantitation of this analysis was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique operating in multiple reaction monitoring positive ion mode. Mass transitions were m/z 323.3 → 83.1 for mequitazine and 281.3 → 86.3 for imipramine as internal standard. Liquid-liquid extraction with ethyl acetate and protein precipitation with methanol were used for sample extraction. Chromatograms showed that the method had high resolution, sensitivity and selectivity without interference from plasma constituents. Calibration curves for mequitazine in rat plasma and urine were 0.02-200 ng/mL, showing excellent linearity with correlation coefficients (r2 ) >0.99. Both intra- and inter-day precisions (CV%) were within 4.08% for rat plasma and urine. The accuracies were 99.58-102.03%. The developed analytical method satisfied the criteria of international guidance. It could be successfully applied to pharmacokinetic studies of mequitazine after oral and intravenous administration to rats.

Effect of Saururus chinensis leaves extract on type II collagen-induced arthritis mouse model.

BACKGROUND: Saururus chinensis leaves have been used as traditional medicine in Korea for pain, intoxication, edema, and furuncle. According to previous reports, these leaves exert renoprotective, neuroprotective, and antioxidant effects by attenuating inflammatory responses. However, the beneficial effect of Saururus chinensis leaves on arthritis has not been elucidated. Thus, we evaluated the water extract of Saururus chinensis leaves (SHW) using type II collagen-induced arthritis (CIA) mice models. METHODS: Quantitative analysis of major components from SHW was performed by HPLC. Arthritis was induced by injection of type II collagen. Each group was orally administered SHW (100 mg/kg and 500 mg/kg). Methotrexate (MTX) was used as a positive control. Serum levels of interleukin-6, TNF-alpha, and type II collagen IgG in the animal models were measured using ELISA. Histological features were observed by H&E staining. RESULTS: Quantitative analysis of SHW showed the contents as 56.4 ± 0.52 mg/g of miquelianin, 7.75 ± 0.08 mg/g of quercetin 3-O-(2"-O-ß -glucopyranosyl)-α-rhamnopyranoside, and 3.17 ± 0.02 mg/g of quercitrin. Treatment with 500 mg/kg SHW decreased the serum level of Interleukin-6 (IL-6), TNF-alpha, and collagen IgG in the CIA model. Moreover, SHW treatment diminished the swelling of hind limbs and monocyte infiltration in blood vessels in CIA animal models. The results indicate that SHW could decrease CIA-induced arthritis in vivo. CONCLUSIONS: The results indicate that SHW could be used to improving arthritis by reducing inflammatory factors (IL-6 and TNF-alpha). However, further experiments are required to determine how SHW influences signal transduction in animal models.

Preparation and In Vitro/In Vivo Characterization of Polymeric Nanoparticles Containing Methotrexate to Improve Lymphatic Delivery.

Methotrexate (MTX) is a folic acid antagonist used as an effective drug to treat various kinds of cancers. However, MTX has limited use in cancer chemotherapy due to its adverse effects such as poor bioavailability, low specificity, drug resistance, and dose-dependent side effects. To improve lymphatic delivery and reduce toxicity of MTX, MTX-loaded nanoparticles (NPs) were prepared in the present study. NPs were prepared with double emulsion solvent evaporation method using poly(lactide-co-glycolide) (PLGA). NPs were assessed for size, encapsulation efficiency, morphology, Fourier-transform infrared spectroscopy, X-ray diffraction, and thermal characterization. In vitro release profiles and cytotoxicity of these NPs were also evaluated. Prepared NPs and free MTX were administered orally or intravenously (5 mg/kg as MTX) to rats to evaluate their pharmacokinetic characteristics and lymphatic delivery effects. Mean particle size and encapsulation efficiency of NPs were 163.7 ± 10.25 nm and 93.3 ± 0.5%, respectively. Prepared NPs showed a sustained release profile of MTX in vitro and may be effective to cancer cells. Area under the blood concentration-time curve, total clearance, half-life, and lymphatic targeting efficiency were significantly different (p < 0.05) between prepared NPs and free MTX. These results demonstrate that MTX-loaded PLGA NPs are good candidates for targeted delivery of MTX to the lymphatic system.