Impact of carbapenem antibiotics on mycophenolate mofetil in hematopoietic stem cell transplant patients with interruption of the enterohepatic recycling: a retrospective study.

Background: Mycophenolate mofetil (MMF), a prodrug of mycophenolic acid (MPA), is widely used in the prophylaxis for graft-versus-host disease (GVHD) following hematopoietic stem cell transplantation (HSCT). MPA undergoes enterohepatic recycling (EHR). Oral antibiotics can affect MPA concentration by reducing intestinal flora-mediated EHR. However, the effect of intravenous antibiotics on MPA concentration is not clear, especially in patients whose EHR is already interrupted. This study was conducted to determine whether intravenous carbapenem antibiotics (CBP) influence the pre-dose plasma concentration (C0) of MPA in HSCT patients when the EHR of MPA is interrupted by cyclosporine and gut decontamination. Methods: The HSCT patients who received immunosuppressive therapy with MMF and cyclosporine, as well as treatment with CBP were screened as potential candidates. Patients who lacked MPA C0 measurements before or during CBP use, had combination therapy of rifampin with MMF, or switched from IV to oral MMF were excluded. The liver/renal function, demographic information, albumin/cyclosporine concentration, MPA C0 and medication information were collected. The changes in the MPA C0 before and during CBP use were evaluated, and the influence of related clinical factors was also estimated. Results: CBP resulted in a significant reduction in the MPA C0 from 0.65±0.33 to 0.43±0.30 µg/mL. Linear regression analysis indicated a weak correlation between the dose-normalized C0 of MPA and the dosage of CBP during CBP use (r2=0.129, P=0.009). Univariate and multivariate analysis confirmed that the MPA C0 had no relevance to rifaximin administration (P=0.249-0.700), demographics (P=0.118-0.599), fluctuation of plasma albumin (ALB, P=0.943 and 0.609) and cyclosporine concentrations (P=0.647 and 0.112), or liver and renal functions (P=0.078-0.887) no matter whether the CBP were used. However, compared with the non-gut decontamination group, larger interindividual variabilities and smaller decreases in MPA C0 (6.60% vs. 41.73%) during CBP therapy were seen in the gut decontamination group, although it was a nonsignificant trend. Conclusions: CBP decreased the MPA C0 in Chinese HSCT patients even when MMF is used in combination with cyclosporine and rifaximin. If antibiotics must be used, and CBP in particular, therapeutic drug monitoring should be performed to ensure adequate exposure.

A clinical study of lyophilized intravenous human immunoglobulin containing high-titer cytomegalovirus-neutralizing antibody for the treatment of cytomegalovirus viremia after allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Cytomegalovirus (CMV) infection increases the risk of death after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, some patients do not respond to ganciclovir (GCV) or foscarnet sodium. Lyophilized intravenous human immunoglobulin containing high-titer CMV-neutralizing antibody (CMV-IVIG) is another option to further improve treatment safety and efficacy. This study was designed to evaluate the efficacy of the combination of CMV-IVIG with traditional antiviral drugs (GCV or foscarnet sodium) at different time points for the treatment of post-allo-HSCT CMV viremia and to determine the clinical value of CMV-IVIG as a preemptive treatment strategy. METHODS: The clinical data of 73 patients who received allo-HSCT and concurrent CMV-IVIG to treat post-allo-HSCT CMV viremia at our hospital between January and September 2020 were retrospectively analyzed. The patients were divided into two groups based on the total dose of antithymocyte globulin (ATG) used in the pretransplant preconditioning regimen, i.e., the low-dose ATG group (rabbit ATG ≤6 mg/kg, porcine ATG ≤40 mg/kg) (n=19) and the high-dose ATG group (rabbit ATG >6 mg/kg, porcine ATG >40 mg/kg) (n=54). Real-time quantitative polymerase chain reaction (RQ-PCR) was performed to measure the peripheral CMV-DNA level. Patients with CMV viremia (CMV-DNA >1,000 copies/mL) received concurrent CMV-IVIG therapy [early (within 3 days after the diagnosis of CMV viremia) or late (after 3 days)]. The CMV-DNA conversion rate, the median time of CMV-DNA conversion, and the two-week response rate and reactivation rate were analyzed for different ATG doses and different time points of CMV-IVIG use. RESULTS: The overall response rate to CMV-IVIG combined with traditional anti-CMV drugs was 100%. Early use of CMV-IVIG significantly reduced the median time of CMV-DNA conversion (14 vs. 21 days, P=0.000), especially in the high-dose ATG group (14 vs. 23 days, P=0.000). CONCLUSIONS: For patients with post-allo-HSCT CMV viremia, early use of CMV-IVIG effectively accelerates CMV-DNA conversion and peripheral CMV clearance, significantly improves the two-week response rate, and reduces the two-week reactivation rate. These effects are more pronounced in the high-dose ATG group.

Dynamic Changes of DNA Methylation Induced by Heat Treatment Were Involved in Ethylene Signal Transmission and Delayed the Postharvest Ripening of Tomato Fruit.

Deoxyribonucleic acid (DNA) methylation plays an important role in fruit ripening and senescence. Here, the role of DNA methylation of the CpG island of SlACS10, LeCTR1, LeEIN3, LeERT10, and SlERF-A1 genes induced by heat treatment (37 °C) in postharvest ripening of tomato fruit was studied. After heat treatment, the firmness and vitamin C content showed higher levels, the loss of aldehydes in volatile components was delayed, and the activities of methylase and demethylase decreased in tomato fruit. Moreover, in heat-treated fruit, significant changes in DNA methylation of SlACS10, LeCTR1, LeEIN3, LeERT10, and SlERF-A1 were induced, the expression of LeERT10 and LeEIN3 was inhibited, the expression of SlERF-A1 was increased, by which ethylene signal transmission might be suppressed and the postharvest ripening of tomato fruit was delayed. The present study provided valuable information for understanding the essential role of DNA methylation in the postharvest ripening of tomato fruit.

Multicenter-Based Population Pharmacokinetic Analysis of Ciclosporin in Hematopoietic Stem Cell Transplantation Patients.

PURPOSE: To explore the contribution of physiological characteristics to variability in ciclosporin pharmacokinetics in hematopoietic stem cell transplantation patients. METHODS: Clinical data from 563 patients were collected from centers in three regions. Ciclosporin concentrations were measured using immunoassays. The patients' demographics, hematological and biological indicators, coadministered drugs, region, and disease diagnosis were recorded from medical records. Data analysis was performed using NONMEM based on a one-compartment model to describe the pharmacokinetics of ciclosporin. The reliability and stability of the final model were evaluated using bootstrap resampling, goodness-of-fit plots, and prediction-corrected visual predictive checks. RESULTS: The population estimate of the clearance (CL) was 30.4 L/h, the volume of distribution (V) was 874.0 L and the bioavailability (F) was 81.1%. The between-subject variability in these parameters was 26.3, 68.0, and 110.8%, respectively. Coadministration of fluconazole, itraconazole, or voriconazole decreased CL by 17.6%, 28.4%, and 29.2%, respectively. Females' CL increased by approximately 12.0%. In addition, CL and V decreased with hematocrit, total protein, and uric acid increase, and CL also decreased with age and aspartate aminotransferase increase. However, CL increased with creatinine clearance increase. CONCLUSIONS: A multicenter-based population pharmacokinetic model of ciclosporin was established. The pharmacokinetics of ciclosporin exhibited discrepancies among different regions.

Analysis of dihydroindole-type alkaloids in Strychnos nux-vomica unprocessed and processed seeds by high-performance liquid chromatography coupled with diode array detection and mass spectrometry.

The ripened seeds of Strychnos nux-vomica L. have been extensively used as herbal medicines in Asian countries. Dihydroindole-type alkaloids are not only the active constituents but also the toxicants in Strychnos. However, the simultaneous determination of these alkaloids in both crude and processed Semen Strychni is still lacking. The present study represents the first quantitation and relative quantitation assay of 12 dihydroindole-type alkaloids in Strychnos nux-vomica unprocessed and sand-processed seeds using high-performance liquid chromatography coupled with diode array detection and mass spectrometry. The relative concentration of ten alkaloids was calculated by semi-quantification using the internal standard and their amounts in unprocessed and detoxified Semen Strychni were compared. We report here for the first time the significant increase of the two alkaloids, 19-N-methyl-strychnine, and 2,3-dimethoxy-19-N-methyl-strychnine, during the processing of Semen Strychni. Our study provides new insight into the true complexity of seed processing procedure and valuable information for assessing the efficacy and safety for clinical applications of Semen Strychni-containing drugs.

Tacrolimus Levels in the Prophylaxis of Acute Graft-Versus-Host Disease in the Chinese Early After Hematopoietic Stem Cell Transplantation.

BACKGROUND: Tacrolimus has been widely accepted as the backbone of acute graft-versus-host disease (aGVHD) prophylaxis in allogeneic hematopoietic stem cell transplantation (alloHSCT). The present work evaluated whether tacrolimus concentrations early after transplant correlate with the incidence of aGVHD in Chinese alloHSCT recipients. METHODS: One hundred four Chinese alloHSCT recipients were included in this retrospective study. All patients received standard prophylaxis with tacrolimus and short-term methotrexate. Blood samples were taken at steady-state for those on i.v. tacrolimus (Cv) or predose (C0) and 2 hours after the last oral dose (C2). RESULTS: In the first 8 weeks after alloHSCT, significant variability in Cv, C0, and C2 of Chinese patients was observed. It was found that higher tacrolimus C0 and C2 values tended to be associated with a reduced risk of aGVHD, although this was a nonsignificant trend due to the small sample size involved. Receiver operating characteristic curve analysis indicated that Cv levels of ≥16.52 ng/mL, C0 levels of ≥5.56 ng/mL, and C2 levels of ≥7.83 ng/mL minimized the incidence of treatment failure during weeks 3-4 with intravenous administration and weeks 5-6 with oral administration. There was no statistically significant association of the patient liver and kidney function with the blood concentration of tacrolimus in the desired range of 5-20 ng/mL. CONCLUSIONS: Tacrolimus therapeutic drug monitoring improved treatment outcomes of Chinese alloHSCT recipients. Cv measurements during weeks 3-4 and C0 or C2 measurements during weeks 5-6 better predicted aGVHD (I-IV) than the concentrations measured at other time points during the first 6 weeks after alloHSCT.

Metabolism of brucine: the important metabolic pathways of dihydroindole-type alkaloid for excretion in rats.

BACKGROUND: Brucine is a widely prescribed glycine antagonist, but a complete understanding of its metabolic pathway is still lacking. The present work represents the first investigation of in vivo metabolism of brucine in rats using LC-ESI-ion trap-TOF-MS. RESULTS: A total of 12 Phase I and five Phase II metabolites were tentatively identified. Brucine can be metabolized by hydrolysis, demethylation and methoxylation, in addition to diverse oxidations in a Phase I manner followed by glucuronidation in Phase II metabolism. Both the renal and biliary routes were observed for the excretion of brucine and its metabolites. CONCLUSION: Our results update the metabolism and disposition data on brucine, which provides basic information for better understanding of the pharmacological and toxicological activities of brucine-containing medicines.

Development and validation of a sensitive LC-MS-MS method for the simultaneous determination of multicomponent contents in artificial Calculus Bovis.

Artificial Calculus Bovis is a major substitute in clinical treatment for Niuhuang, a widely used, efficacious but rare traditional Chinese medicine. However, its chemical structures and the physicochemical properties of its components are complicated, which causes difficulty in establishing a set of effective and comprehensive methods for its identification and quality control. In this study, a simple, sensitive and reliable liquid chromatography-tandem mass spectrometry method was successfully developed and validated for the simultaneous determination of bilirubin, taurine and major bile acids (including six unconjugated bile acids, two glycine-conjugated bile acids and three taurine-conjugated bile acids) in artificial Calculus Bovis using a Zorbax SB-C18 column with a gradient elution of methanol and 10 mmol/L ammonium acetate in aqueous solution (adjusted to pH 3.0 with formic acid). The mass spectra were obtained in the negative ion mode using dehydrocholic acid as the internal standard. The content of each analyte in artificial Calculus Bovis was determined by monitoring specific ion pairs in the selected reaction monitoring mode. All analytes demonstrated perfect linearity (r(2) > 0.994) in a wide dynamic range, and 10 batches of samples from different sources were further analyzed. This study provided a comprehensive method for the quality control of artificial Calculus Bovis.

Characterisation and identification of dihydroindole-type alkaloids from processed semen strychni by high-performance liquid chromatography coupled with electrospray ionisation ion trap time-of-flight mass spectrometry.

INTRODUCTION: For centuries, Semen Strychni (the ripened seeds of Strychnos nux-vomica) has been used extensively as a herbal medicine in Asian countries. However, the chemical composition of the dihydroindole-type alkaloids contained in processed Semen Strychni is not fully understood. OBJECTIVE: To develop an improved strategy using mass defect filtering (MDF) in combination with MS(n) analysis and theoretical calculations for identification and structural characterisation of dihydroindole-type alkaloids in processed Semen Strychni extracts. METHODS: The experimental work was conducted using a high-performance liquid chromatography coupled with electrospray ionisation ion trap time-of-flight mass spectrometry (HPLC-ESI/IT-TOF/MS) system. Upon acquisition of full-scan MS data, the potential dihydroindole-type alkaloids were screened using a well-defined mass defect range of 50 mDa. With the assistance of MS(n) analysis, the diagnostic fragment ions (DFIs) were used as primary screening references for targeting the characteristic analogues. For better discrimination of the isomers, quantum chemical calculations were utilised to provide additional structural information. RESULTS: Twenty-four dihydroindole-type alkaloids, including four that were previously not described, were tentatively identified. CONCLUSION: A new, rapid and sensitive method was developed for the discovery and characterisation of dihydroindole-type alkaloids in extracts of processed Semen Strychni. The successful application of this method indicates a potential for adaptation to other classes of natural product from other sources.

Herb-drug pharmacokinetic interaction of artificial calculus bovis with diclofenac sodium and chlorpheniramine maleate in rats.

OBJECTIVES: To investigate the herb-drug pharmacokinetic interaction of artificial calculus bovis (ACB) with diclofenac sodium (DS) and chlorpheniramine maleate (CPM) in rats. METHODS: A sensitive high-performance liquid chromatography coupled with tandem mass spectrometry method was developed and validated for the simultaneous determination of DS and CPM in rat plasma. The proposed method was successfully applied to compare the herb-drug pharmacokinetic interaction of ACB with DS and CPM in rats following intragastric administration. KEY FINDINGS: The proposed method had good linearity and no endogenous material interfered with the analytes and internal standard peaks. The lower limit of quantification of DS and CPM was 1 and 0.1 ng/ml, respectively. There was no apparent pharmacokinetic interaction between DS and CPM. Co-administration of ACB with DS noticeably increased the area under the concentration-time curve (AUC0-∞ ) and peak plasma concentration (Cmax ) of DS, while the parameters time of peak concentration (Tmax ), clearance (ClZ/F ) and apparent volume of distribution (VZ/F ) of DS significantly decreased. Meanwhile, co-administration of ACB with CPM noticeably increased the Tmax , ClZ/F and VZ/F of CPM. A marked decline in AUC0-∞ and Cmax of CPM occurred in the presence of ACB. CONCLUSIONS: This study indicated that co-administration of ACB with DS and CPM can result in an apparent herb-drug pharmacokinetic interaction in rats.

In vitro metabolism study of Strychnos alkaloids using high-performance liquid chromatography combined with hybrid ion trap/time-of-flight mass spectrometry.

In this report, the in vitro metabolism of Strychnos alkaloids was investigated using liquid chromatography/high-resolution mass spectrometry for the first time. Strychnine and brucine were selected as model compounds to determine the universal biotransformations of the Strychnos alkaloids in rat liver microsomes. The incubation mixtures were separated by a bidentate-C18 column, and then analyzed by on-line ion trap/time-of-flight mass spectrometry. With the assistance of mass defect filtering technique, full-scan accurate mass datasets were processed for the discovery of the related metabolites. The structural elucidations of these metabolites were achieved by comparing the changes in accurate molecular masses, calculating chemical component using Formula Predictor software and defining sites of biotransformation based upon accurate MS(n) spectral information. As a result, 31 metabolites were identified, of which 26 metabolites were reported for the first time. These biotransformations included hydroxylation, N-oxidation, epoxidation, methylation, dehydrogenation, de-methoxylation, O-demethylation, as well as hydrolysis reactions.

Analysis of saikosaponins in rat plasma by anionic adducts-based liquid chromatography tandem mass spectrometry method.

Saikosaponins (SSs) are a class of triterpene saponins with a wide spectrum of bioactivities. A sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of saikosaponin a, saikosaponin c, saikosaponin d and saikosaponin b2 in rat plasma. Plasma samples were prepared by liquid-liquid extraction. The analytes and the internal standard (IS) digoxin were well separated on an octadecyl column using gradient elution and analyzed by monitoring the fragmentation transition pair of anionic adducts to deprotonated molecules in negative-mode electrospray. By neutral loss of HCOOH, the transition pairs of m/z 825 → 779 for SSa, SSd, SSb2 and the IS, and m/z 971 → 925 for SSc were sensitive for MS/MS detection with the lower limits of quantification in the range of 0.20-0.40 ng/mL. Method validation experiments were performed, including selectivity, precision, accuracy, linearity, matrix effect, recovery and stability. The validated method was further applied to determine the pharmacokinetics parameters of SSa, c and d in rats following a single oral administration of the extract of chaihu (the dried roots of Bupleurum chinense DC).

Simultaneous determination of codeine, ephedrine, guaiphenesin and chlorpheniramine in beagle dog plasma using high performance liquid chromatography coupled with tandem mass spectrometric detection: application to a bioequivalence study.

A rapid and sensitive method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of codeine, ephedrine, guaiphenesin and chlorpheniramine in beagle dog plasma has been developed and validated. Following liquid-liquid extraction, the analytes were separated on a reversed-phase C(18) column (150 mm × 2.0 mm, 3 µm) using formic acid:10 mM ammonium acetate:methanol (0.2:62:38, v/v/v) as mobile phase at a flow rate of 0.2 mL/min and analyzed by a triple-quadrupole mass spectrometer in the selected reaction monitoring (SRM) mode. The method was linear for all analytes over the following concentration (ng/mL) ranges: codeine 0.08-16; ephedrine 0.8-160; guaiphenesin 80-16,000; chlorpheniramine 0.2-40. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. It is the first time that the validated HPLC-MS/MS method was successfully applied to a bioequivalence study in 6 healthy beagle dogs.

Pharmacokinetics and bioequivalence study of valacyclovir hydrochloride capsules after single dose administration in healthy Chinese male volunteers.

The aim of the present study was to compare the bioavailability of valacyclovir (CAS 124832-26-4; INN: valaciclovir) from two valacyclovir hydrochloride (CAS 214832-27-5) capsules (150 mg/capsule as test preparation and 150 mg/capsule commercially available original capsule of the drug as reference preparation) in 20 Chinese healthy male volunteers, aged between 20 and 27. The study was conducted according to an open, randomized, single blind, 2-way crossover study design with a wash-out phase of 7 days. Blood samples for pharmacokinetic profiling were taken up to 24 h post-dose. Valacyclovir hydrochloride is rapidly converted to acyclovir (CAS 59277-89-3) after oral administration, so the pharmacokinetics and bioequivalence of valacyclovir hydrochloride can be studied by determining the plasma concentration of acyclovir. Plasma concentrations of acyclovir were determined with a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The pharmacokinetic parameters of test and reference formulations were estimated as follows: the maximum plasma concentrations (C(max)) were 2.04 +/- 0.43 microg/mL and 2.01 +/- 0.50 microg/mL; the median T(max) were 1.1 +/- 0.3 h and 1.0 +/- 0.3 h; plasma elimination half-lives (t1/2) were 2.94 +/- 0.42 h and 2.85 +/- 0.28 h. Values of AUC(0-t) demonstrate nearly identical bioavailability of valacyclovir hydrochloride from the examined formulations. AUC(0-15) were 6.70 +/- 1.26 microg x h/ mL and 6.96 +/- 1.25 microg x h/mL. Areas under the plasma concentration-time curve (AUC(0-infinity)) were 6.90 +/- 1.30 microg x h/mL and 7.15 +/- 1.31 microg x h/mL. Both primary target parameters, AUC(0-infinity) and AUC(0-t) were tested parametrically by analysis of variance (ANOVA) and relative bioavailabilities were 96.69 +/- 7.89% for AUC(0-infinity), 96.40 +/- 8.0% for AUC(0-15). Bioequivalence between test and reference preparation was demonstrated for both parameters, AUC(0-infinity) and AUC(0-t). The 90% confidence intervals of the T/R-ratios of logarithmically transformed data were in the generally accepted range of 80-125%. It meant that the test formulation was bioequivalent to the reference formulation for valacyclovir hydrochloride.