Development of a LC-MS/MS method for simultaneous determination of metoprolol and its metabolites, α-hydroxymetoprolol and O-desmethylmetoprolol, in rat plasma: application to the herb-drug interaction study of metoprolol and breviscapine

Identification of Metoprolol Tartrate-Derived Reactive Metabolites Possibly Correlated with Its Cytotoxicity

As a selective β₁-receptor antagonist, metoprolol tartrate (MTA) is commonly used to treat cardiovascular diseases such as hypertension and angina pectoris. There have been cases of liver injury induced by MTA, but the mechanism of hepatotoxicity induced by MTA is not clear. The purposes of this study were to identify the reactive metabolites of MTA, to determine the pathway for the metabolic activation of MTA, and to define a possible correlation between the metabolic activation and cytotoxicity of MTA. Three oxidative metabolites (M1-M3), a glutathione (GSH) conjugate (M4), and an N-acetyl cysteine (NAC) conjugate (M5) were detected in rat liver microsomal incubations containing MTA and GSH or NAC. M4 was also detected in cultured rat primary hepatocytes and bile of rats given MTA, and M5 was detected in the urine of MTA-treated rats. A quinone methide intermediate may be produced from the metabolic activation process in vitro and in vivo. The metabolite was reactive to glutathione and N-acetyl cysteine. MTA induced marked cytotoxicity in cultured rat primary hepatocytes. Pretreatment of aminobenzotriazole, a nonselective P450 enzyme inhibitor, attenuated the susceptibility of hepatocytes to MTA cytotoxicity.

Development and Validation of a Method for Simultaneous Estimation of Sitagliptin and Ertugliflozin in Rat Plasma by LC-MS method

Background:

The development of sound bioanalytical LC-MS (liquid chromatography-mass spectroscopy) method(s) is of paramount importance during the process of drug discovery, development and culminating in a marketing approval. The use of oral antidiabetic agents has been increased significantly from the last decades and till now no bioanalytical method is available for quantitation of sitagliptin (SG) and ertugliflozin (EG) in biological matrix which can be applied to pharmacokinetic studies using LC-MS/MS.

Objective:

To develop a new, rapid and sensitive LC–MS/MS method for the simultaneous estimation of sitagliptin (SG) and ertugliflozin (EG) in rat plasma by liquid–liquid extraction method (LLE) using deutereated sitagliptin (SGd6) and ertugliflozin (EGd6).

Methods:

Chromatographic separation was carried out on a reverse phase Waters, Xetrra C18 (150mm x 4.6mm, 2μm) column using a mixture of acetonitrile and OPA buffer (50:50v/v) at a flow rate of 1ml/min in isocratic mode. Quantification was achieved using an electrospray ion interface operating in positive mode, under Multiple Reaction Monitoring (MRM) conditions.

Results:

The method showed excellent linearity over the concentration range of 5.00- 75.00pg/mL for sitagliptin and 0.75- 11.35pg/mL ertugliflozin. The intra-batch and inter batch precision (%CV) was ≤ 4.3% and matrix effect (%CV) was 0.02% and 0.12% for sitagliptin at HQC and LQC, respectively. Matrix effect (%CV) was 0.08% and 0.33% for ertugliflozin at HQC and LQC, respectively.

Conclusion:

The simplicity of the method allows for application in laboratories, presents a valuable tool for pharmacokinetic studies. The particular assay has been proficiently put on pharmacokinetic study in rats subjects.

Direct analysis in real time-mass spectrometry for rapid quantification of five anti-arrhythmic drugs in human serum: application to therapeutic drug monitoring

Therapeutic drug monitoring (TDM) is necessary for the optimal administration of anti-arrhythmic drugs in the treatment of heart arrhythmia. The present study aimed to develop and validate a direct analysis in real time tandem mass spectrometry (DART–MS/MS) method for the rapid and simultaneous determination of five anti-arrhythmic drugs (metoprolol, diltiazem, amiodarone, propafenone, and verapamil) and one metabolite (5-hydroxy(OH)-propafenone) in human serum. After the addition of isotope-labeled internal standards and protein precipitation with acetonitrile, anti-arrhythmic drugs were ionized by DART in positive mode followed by multiple reaction monitoring (MRM) detection. The use of DART–MS/MS avoided the need for chromatographic separation and allowed rapid and ultrahigh throughput analysis of anti-arrhythmic drugs in a total run time of 30 s per sample. The DART–MS/MS method yielded satisfactory linearity (R² ≥ 0.9906), accuracy (86.1–109.9%), and precision (≤ 14.3%) with minimal effect of biological matrixes. The method was successfully applied to analyzing 30 clinical TDM samples. The relative error (RE) of the concentrations obtained by DART–MS/MS and liquid chromatography-tandem mass spectrometry (LC–MS/MS) was within ± 13%. This work highlights the potential usefulness of DART for the rapid quantitative analysis of anti-arrhythmic drugs in human serum and gives rapid feedback in the clinical TDM practices.

Metabolomic profiling of metoprolol hypertension treatment reveals altered gut microbiota-derived urinary metabolites

Introduction

Metoprolol succinate is a long-acting beta-blocker prescribed for the management of hypertension (HTN) and other cardiovascular diseases. Metabolomics, the study of end-stage metabolites of upstream biologic processes, yield insight into mechanisms of drug effectiveness and safety. Our aim was to determine metabolomic profiles associated with metoprolol effectiveness for the treatment of hypertension.

Methods

We performed a prospective pragmatic trial (NCT02293096) that enrolled patients between 30 and 80 years with uncontrolled HTN. Patients were started on metoprolol succinate at a dose based upon systolic blood pressure (SBP). Urine and blood pressure measurements were collected weekly. Individuals with a 10% decline in SBP or heart rate (HR) were considered responsive. Genotype for the CYP2D6 enzyme, the primary metabolic pathway for metoprolol, was evaluated for each subject. Unbiased metabolomic analyses were performed on urine samples using UPLC-QTOF mass spectrometry.

Results

Urinary metoprolol metabolite ratios are indicative of patient CYP2D6 genotypes. Patients taking metoprolol had significantly higher urinary levels of many gut microbiota-dependent metabolites including hydroxyhippuric acid, hippuric acid, and methyluric acid. Urinary metoprolol metabolite profiles of normal metabolizer (NM) patients more closely correlate to ultra-rapid metabolizer (UM) patients than NM patients. Metabolites did not predict either 10% SBP or HR decline.

Conclusion

In summary, urinary metabolites predict CYP2D6 genotype in hypertensive patients taking metoprolol. Metoprolol succinate therapy affects the microbiome-derived metabolites.

Simultaneous Determination of Imatinib and N-Desmethyl Imatinib in Rat Plasma and Tissues Using LC-MS/MS

Background:

Imatinib (IM) is a chemotherapy medication metabolized by CYP3A4 to Ndesmethyl imatinib (NDI), which shows similar pharmacologic activity to the parent drug. Although methods for determination of IM and/or NDI have been developed extensively, only few observations have been addressed to simultaneously determine IM and NDI in biological tissues such as liver, kidney, heart, brain and bone marrow.

Methods:

A validated LC-MS/MS method was developed for the quantitative determination of imatinib (IM) and N-desmethyl imatinib (NDI) from rat plasma, bone marrow, brain, heart, liver and kidney. The plasma samples were prepared by protein precipitation, and then the separation of the analytes was achieved using an Agilent Zorbax Eclipse Plus C18 column (4.6 × 100 mm, 3.5 µm) with gradient elution running water (A) and methanol (B). Mass spectrometric detection was achieved by a triplequadrupole mass spectrometer equipped with an electrospray source interface in positive ionization mode.

Results:

This method was used to investigate the pharmacokinetics and the tissue distributions in rats following oral administration of 25 mg/kg of IM. The pharmacokinetic profiles suggested that IM and NDI are disappeared faster in rats than human, and the tissue distribution results showed that IM and NDI had good tissue penetration and distribution, except for the brain. This is the first report about the large penetrations of IM and NDI in rat bone marrow.

Conclusion:

The method demonstrated good sensitivity, accuracy, precision and recovery in assays of IM and NDI in rats. The described assay was successfully applied for the evaluation of pharmacokinetics and distribution in the brain, heart, liver, kidney and bone marrow of IM and NDI after a single oral administration of IM to rats.

Pharmacokinetic Analysis of Four Bioactive Iridoid and Secoiridoid Glycoside Components of Radix Gentianae Macrophyllae and Their Synergistic Excretion by HPLC-DAD Combined with Second-Order Calibration

An HPLC-DAD method combined with second-order calibration based on the alternating trilinear decomposition (ATLD) algorithm with the aid of region selection was developed to simultaneously and quantitatively characterize the synergistic relationships and cumulative excretion of the four bioactive ingredients of Radix Gentianae Macrophyllae in vivo. Although the analytes spectra substantially overlapped with that of the biological matrix, the overlapping profiles between analytes and co-eluting interferences can be successfully separated and accurately quantified by the ATLD method on the basis of the strength of region selection. The proposed approach not only determined the content change but also revealed the synergistic relationships and the cumulative excretion in vivo of the four ingredients in urine and feces samples collected at different excretion time intervals. In addition, several statistical parameters were employed to evaluate the accuracy and precision of the method. Quantitative results were confirmed by HPLC-mass spectrometry. Satisfactory results indicated that the proposed approach can be utilized to investigate the pharmacokinetics of Radix Gentianae Macrophyllae excretion in vivo.

An evaluation of the CYP2D6 and CYP3A4 inhibition potential of metoprolol metabolites and their contribution to drug-drug and drug-herb interaction by LC-ESI/MS/MS

The aim of the present study was to evaluate the contribution of metabolites to drug-drug interaction and drug-herb interaction using the inhibition of CYP2D6 and CYP3A4 by metoprolol (MET) and its metabolites. The peak concentrations of unbound plasma concentration of MET, α-hydroxy metoprolol (HM), O-desmethyl metoprolol (ODM) and N-desisopropyl metoprolol (DIM) were 90.37 ± 2.69, 33.32 ± 1.92, 16.93 ± 1.70 and 7.96 ± 0.94 ng/mL, respectively. The metabolites identified, HM and ODM, had a ratio of metabolic area under the concentration-time curve (AUC) to parent AUC of ≥0.25 when either total or unbound concentration of metabolite was considered. In vitro CYP2D6 and CYP3A4 inhibition by MET, HM and ODM study revealed that MET, HM and ODM were not inhibitors of CYP3A4-catalyzed midazolam metabolism and CYP2D6-catalyzed dextromethorphan metabolism. However, DIM only met the criteria of >10% of the total drug related material and <25% of the parent using unbound concentrations. If CYP inhibition testing is solely based on metabolite exposure, DIM metabolite would probably not be considered. However, the present study has demonstrated that DIM contributes significantly to in vitro drug-drug interaction. Copyright © 2016 John Wiley & Sons, Ltd.