Synthesis,characterization and theoretical and fluorescence emission microscopy studies of new Pd/Pt–cyclopropa[60]fullerene complexes: Application of Taguchi method for optimization of parameters in Suzuki–Miyaura reaction

The reactions of unsymmetric phosphorus ylides of the type [Ph₂P(CH₂)_nPPh₂?C(H)C(O)C₆H₄‐p‐CN] (n = 1 (Y¹); n = 2 (Y²)) with C₆₀ and M(dba)₂ (M = Pd or Pt; dba = dibenzylideneacetone) are reported. Based on the various coordination modes of these ylides in complexation, the following new Pd/Pt–cyclopropa[60]fullerene complexes were obtained: P,C‐coordinated [(η²‐C₆₀)Pd(κ²‐Y¹)] ( 1 ) and [(η²‐C₆₀)Pt(κ²‐Y¹)] ( 2 ) complexes and P‐coordinated [(η²‐C₆₀)Pd(Y²)₂] ( 3 ) and [(η²‐C₆₀)Pt(Y²)₂] ( 4 ) complexes. These compounds were characterized using Fourier transform infrared, UV–visible and NMR (¹H, ¹³C and ³¹P) spectroscopies and scanning electron microscopy. Furthermore, cytotoxicity studies showed that nanoparticles of these complexes can be used as non‐toxic labels for cellular imaging application. Also energy decomposition analysis results revealed that the percentage contribution of ΔE_elec in total interaction energy is considerably larger than that of ΔE_orb. Thus, in all complexes the (η²‐C₆₀)M? (Y¹) bond is considerably more electrostatic in nature than the (η²‐C₆₀)? M(Y¹) bond. Finally, by application of the Taguchi method for optimization of parameters in Suzuki–Miyaura reaction, the catalytic activity of Pd complexes 1 and 3 was investigated in the cross‐coupling reaction of various aryl chlorides with phenylboronic acid. According to analysis of variance results, solvent has the highest F value and it has high contribution percentage (36.75%) to the yield of Suzuki–Miyaura reaction.     

Pharmacokinetics,bioavailability and tissue distribution studies of rhodojaponin III in mice using QTRAP LC–MS/MS

Rhodojaponin III is a bioactive diterpenoid isolated from the medicinal plant Rhododendron molle G. Don. Quantitative analysis of rhodojaponin III was challenging and the pharmacokinetics of oral rhodojaponin III remained to be investigated. Here, a rapid and sensitive liquid chromatography tandem mass spectrometric (LC–MS/MS) method was developed and validated. The calibration curve was linear over the concentration range of 1–200 ng/mL (r = 0.992). The method was further validated following internationally approved guidelines and all the issues including intra‐ and inter‐day precision, accuracy, carryover, extraction recovery, matrix effects and stability met the recommended limits. The method was then applied to study the pharmacokinetics of rhodojaponin III in mice after intravenous (0.06 mg/kg) or oral (0.24 mg/kg) administration. The results showed that rhodojaponin III had fast oral absorption (time to peak concentration, 0.08 h) and good oral bioavailability (73.6%). In addition, rhodojaponin III was quickly eliminated after it was intravenously or orally administered, with half‐life values of 0.19 and 0.76 h, respectively. After oral administration, it was widely distributed in tissues including kidney, lung, heart, spleen and thymus, but had extremely low concentrations in liver and brain. The data presented in this study is beneficial for the further study of rhodojaponin III.     

Development of an LC–MS/MS method for quantification of two pairs of isomeric flavonoid glycosides and other ones in rat plasma: Application to pharmacokinetic studies

A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for simultaneous determination of six flavonoid glycosides – isoorientin ( 1 ), orientin ( 2 ), 2″‐O‐β ‐d ‐xylopyranosyl isoorientin ( 3 ), 2″‐O‐β ‐d ‐xylopyranosyl isovitexin ( 4 ), 6‐C‐l ‐α ‐arabipyranosyl vitexin ( 5 ) and vitexin ( 6 ) – in rat plasma using isoquercitrin as the internal standard (IS). Plasma samples were prepared by a one‐step protein precipitation with acetonitrile. Chromatographic analysis was carried out on a 25 cm C₁₈ column with a gradient mobile phase consisting of acetonitrile and 0.1% aqueous formic acid. Six analytes and IS were detected through electrospray ionization in negative‐ion selection reaction monitoring mode. The mass transitions were as follows: m/z 447.2 → 327.0 for 1 , m/z 447.2 → 327.0 for 2 , m/z 579.3 → 458.9 for 3 , m/z 563.0 → 293.1 for 4 , m/z 563.0 → 353.0 for 5 , m/z 431.1 → 311.1 for 6 , and m/z 463.1 → 300.2 for IS. Calibration curves exhibited good linearity (r ² > 0.9908) over a wide concentration range for all compounds. Intra‐ and inter‐day precision (RSD, %) at four different levels were both <14.2% and the accuracy (RE, %) ranged from −11.9 to 12.0%. The extraction recoveries of the six components ranged from 88.2 to 103.6%. The validated assay was successfully applied to the pharmacokinetic studies of the six components in male rat plasma after intravenous administration of total flavonoids of Scorzonera austriaca Wild.     

LC–ESI–MS/MS determination of copanlisib,a novel PI3K inhibitor,in mouse plasma and its application to a pharmacokinetic study in mice

A sensitive, selective and rapid LC–ESI–MS/MS method has been developed and validated for the quantification of copanlisib in mouse plasma using enasidenib as an internal standard (IS) as per regulatory guideline. Copanlisib and the IS were extracted from mouse plasma using ethyl acetate as an extraction solvent and chromatographed using an isocratic mobile phase (0.2% formic acid–acetonitrile; 25:75, v/v) on a HyPURITY C₁₈ column. Copanlisib and the IS eluted at ~0.95 and 2.00 min, respectively. The MS/MS ion transitions monitored were m/z 481.1 → 360.1 and m/z 474.0 → 456.0 for copanlisib and the IS, respectively. The calibration range was 3.59–3588 ng/mL. The intra‐ and inter‐batch accuracy and precision (RE and RSD) across quality controls met the acceptance criteria. Stability studies showed that copanlisib was stable in mouse plasma for one month. This novel method has been applied to a pharmacokinetic study in mice.     

In vivo metabolic investigation of silodosin using UHPLC–QTOF–MS/MS and in silico toxicological screening of its metabolites

Silodosin (SLD) is a novel α1‐adrenoceptor antagonist which has shown promising clinical efficacy and safety in patients with benign prostatic hyperplasia (BPH). However, lack of information about metabolism of SLD prompted us to investigate metabolic fate of SLD in rats. To identify in vivo metabolites of SLD, urine, feces and plasma were collected from Sprague–Dawley rats after its oral administration. The samples were prepared using an optimized sample preparation approach involving protein precipitation followed by solid‐phase extraction and then subjected to LC/HR‐MS/MS analysis. A total of 13 phase I and six phase II metabolites of SLD have been identified in rat urine which includes hydroxylated, N‐dealkylated, dehydrogenated, oxidative, glucosylated, glucuronide and N‐sulphated metabolites, which are also observed in feces. In plasma, only dehydrogenated, N‐dealkylated and unchanged SLD are observed. The structure elucidation of metabolites was done by fragmentation in MS/MS in combination with HRMS data. The potential toxicity profile of SLD and its metabolites were predicted using TOPKAT software and most of the metabolites were proposed to show a certain degree of skin sensitization and occular irritancy. Copyright © 2016 John Wiley & Sons, Ltd.     

Simultaneous determination of wogonin,oroxylin a,schisandrin, paeoniflorin and emodin in rat serum by HPLC–MS/MS and application to pharmacokinetic studies

Wogonin and oroxylin A in Scutellariae Radix, schisandrin in Chinensis Fructus, paeoniflorin in Moutan Cortex and emodin in Polygoni Cuspidate Rhizome et Radix are anti‐inflammatory active compounds. A method for simultaneous determination of the five compounds in rat was developed and validated using high‐performance liquid chromatography with tandem mass spectrometry (HPLC–MS/MS). The separation was performed on a Symmetry C₁₈ column (4.6 × 50 mm, 3.5 μm) with acetonitrile and 0.1% formic acid aqueous solution as the mobile phases. The detection was performed using multiple‐reaction monitoring with electrospray ionization source in positive–negative ion mode. The calibration curves showed good linearity (r ≥ 0.9955). The lower limit of quantification (LLOQ) was 5 ng/mL for wogonin and schisandrin, 10 ng/mL for oroxylin A and emodin, and 15 ng/mL for paeoniflorin, respectively. The relative standard deviations of intraday and interday precisions were <11.49 and 14.28%, respectively. The extraction recoveries and matrix effects were acceptable. The analytes were stable under the experiment conditions. The validated method has been successfully applied to pharmacokinetic studies of the five compounds in rats after oral administration of Hu‐gan‐kan‐kang‐yuan capsule. This paper would be a valuable reference for pharmacokinetic studies of Chinese medicine preparations containing the five compounds.     

Characterization and screening of metals,metalloids and biomarkers in crude oil by ICP–MS/OES,and GC–MS techniques after digestion by microwave‐induced combustion

A method for digestion of light and medium Iraqi crude oils (Basrah and Khanaken oils) using microwave‐induced combustion (MIC) in closed vessels is described for the determination of Hg, Au, Cu, Al, Ca, Co, K, Mg, Si and Sr by inductively coupled plasma optical emission spectrometry (ICP–OES) and Mo, Ti, Mn, Li, Se^?1, Rb, Ag, Ba, Pb, As, Cd, Cr, Fe, Ni, V and Zn by inductively coupled plasma mass spectrometry (ICP–MS). Upon using MIC it was possible to obtain lower limits of detection by ICP–MS and also by ICP–OES compared with those obtained by microwave‐assisted digestion. The MIC was the best choice with regard to the possibility of using dilute nitric acid as an absorbing solution, which is important to minimize the interference encountered by ICP–MS and ICP–OES.The physicochemical parameters and some contaminants of crude oil samples were analyzed to classify and assess the quality of the crude oils. This study determines the viability of the use of Fourier transform infrared spectroscopy as an alternativee to traditional petroleum geochemical methods for crude oil characterization. The infrared fingerprints agree with the results obtained from GC–MS analysis.     

Safety evaluation of Semen Sojae Preparatum based on simultaneous LC–ESI–MS/MS quantification of aflatoxin B1, B2, G1, G2 and M1

Semen Sojae Preparatum (SSP) is one of the most widely used traditional Chinese medicines, and is also a functional food. However, contamination with aflatoxins may occur in the fermentation process. To evaluate its safety, an accurate and rapid LC–ESI–MS/MS analytical method was developed and validated for the simultaneous determination of AFB₁, AFB₂, AFG₁, AFG₂ and AFM₁ in SSP. After a simple ultrasonic extraction of SSP samples, chromatographic separation was achieved on an Agilent Zorbax SB‐C₁₈ column (2.1 × 50 mm, 3.5 μm) with a flow rate of 0.50 mL/min. The gradient elution program was performed using a mobile phase consisting of water and acetonitrile, both containing 0.1% formic acid. Detection of five aflatoxins was based on triple quadrupole mass spectrometry using a multiple reaction monitoring mode with an electrospray ionization source. SSP is likely to be contaminated by aflatoxins in the processes of fermentation, storage, transportation and usage, and it is necessary to strictly monitor it. Artemisia annua L. and Morus alba L. may inhibit the production and growth of AFB₁‐ and AFB₂‐producing fungi, which has a certain detoxification effect on contamination with aflatoxins in SSP.     

Analysis of aflatoxins in nonalcoholic beer using liquid–liquid extraction and ultraperformance LC‐MS/MS

Aflatoxins AFB1, AFB2, AFG1, and AFG2 are toxic secondary metabolites produced by Aspergillus flavus and Aspergillus parasiticus and posses a potential threat to food safety. In the present work, liquid–liquid extraction and ultraperformance LC‐MS/MS method has been applied for the determination of four naturally occurring aflatoxins AFB1, AFB2, AFG1, and AFG2 in nonalcoholic beer. Aflatoxins extraction from nonalcoholic beer was carried out using liquid–liquid extraction procedure. The effects of solvent‐types were studied to obtain maximum recovery of the target analytes with minimum contamination. Among different solvents, the aflatoxins extraction was best achieved using ethyl acetate. The obtained recoveries were ranged from 85 to 96% with good quality parameters: LOD values between 0.001 and 0.003 ng/mL, linearity of the calibration curve (r² > 0.999), and repeatability (run‐to‐run) and reproducibility (day‐to‐day) precisions with RSDs lower than 5% (n = 5) achieved at 0.50 ng/mL concentration. The optimized liquid–liquid extraction in combination with ultraperformance LC‐MS/MS was applied successfully to the analysis of AFB1, AFB2, AFG1, and AFG2 aflatoxins in 11 nonalcoholic beers and were detected up to 15.31 ng/L in some of the samples.     

Pharmacokinetic studies of a novel trioxane antimalarial (99/411) in rats and monkeys using LC–MS/MS

The pharmacokinetic profile of 99/411, a novel anti‐malarial drug, was established in rats (12 mg/kg of body weight) and monkeys (20 mg/kg of body weight). Following oral administration, the presence of 99/411 was rapidly determined in rat plasma, tissues, urine, feces and monkey plasma using a validated LC–MS/MS method. The tissue distribution studies in rats indicated that the drug was partially distributed in all major tissues and plasma, and peak concentration levels were achieved within 0.5–4 h. Area under the curve in different rat tissues and plasma was found in order of blood > lung > intestine > heart > muscle > brain > kidney > spleen > liver. The total recoveries (within 86 h) of 99/411 were <0.0017% and <0.08% in urine and feces, respectively. The peak plasma concentration was 3499 ng/mL in rats after ~2 h of oral administration and 697–767 ng/mL in monkeys after ~6 h of oral administration. No plasma accumulation was observed in both male and female monkeys, even after multiple dosing. The preclinical pharmacokinetic profile and tissue distribution data are expected to assist in future clinical explorations of 99/411 as a promising anti‐malarial agent.     

A robust LC–MS/MS method for the simultaneous determination of docetaxel and voriconazole in rat plasma and its application to pharmacokinetic studies

Opportunistic fungal infections are common in immunocompromised cancer patients, especially patients undergoing chemotherapy. Because antitumor agents are possible to combine with antifungal agents in clinical, it is necessary to study drug–drug interaction between antitumor agents and antifungal agents. The aim of the study was to explore a method for the simultaneous determination of voriconazole and docetaxel in plasma and investigate pharmacokinetic interaction of voriconazole and docetaxel in rats. A precise and reliable method using liquid chromatography tandem mass spectrometry (LC–MS/MS) was established for the simultaneous measure of docetaxel and voriconazole in rat plasma after liquid–liquid extraction with ethyl acetate. The method was fully validated and successfully applied to a pharmacokinetic interaction study of docetaxel and voriconazole in rats after single or combined administration. We found that the AUC of each drug after coadministration increased compared with that after the single administration, which might be caused by interaction at the absorption stage or the competitive inhibition on the metabolic enzymes. This established method can be utilized to study the detailed mechanism of the drug–drug interaction and guide rational drug use in the clinic.     

Vitrification/devitrification phenomena during isothermal and nonisothermal crystallization of poly(aryl–ether–ether–ketone) (PEEK) and PEEK/poly(ether–imide) blends

We have established time–temperature transformation and continuous-heating transformation diagrams for poly(ether–ether–ketone) (PEEK) and PEEK/poly(ether–imide) (PEI) blends, in order to analyze the effects of relaxation control on crystallization. Similar diagrams are widely used in the field of thermosetting resins. Upon crystallization, the glass transition temperature (T_g) of PEEK and PEEK/PEI blends is found to increase significantly. In the case of PEEK, the shift of the α-relaxation is due to the progressive constraining of amorphous regions by nearby crystals. This phenomenon results in the isothermal vitrification of PEEK during its latest crystallization stages for crystallization temperatures near the initial T_g of PEEK. However, vitrification/devitrification effects are found to be of minor importance for anisothermal crystallization, above 0.1°C/min heating rate. In the case of PEEK/PEI blends, amorphous regions are progressively enriched in PEI upon PEEK crystallization. This promotes a shift of the α-relaxation of these regions to higher temperatures, with a consequent vitrification of the material when crystallized below the T_g of PEI. The data obtained for the blends in anisothermal regimes allow one to detect a region in the (temperature/heating rate) plane where crystallization proceeds in the continuously close proximity of the glass transition (dynamic vitrification). These experimental findings are in agreement with simple simulations based on a modified Avrami model coupled with the Fox equation. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 919–930, 1998     

Validated LC–MS/MS method for the quantification of sciadopitysin in rat plasma and its application to pharmacokinetic and bioavailability studies in vivo

A sensitive and rapid LC–MS/MS method was developed and validated for quantitation of sciadopitysin in rat plasma using amentoflavone as an internal standard. Sample processing was accomplished after deproteinization with 150 μL aliquot of acetonitrile. Chromatographic separation was achieved using an Agela C₁₈ column with an isocratic mobile phase comprising 2 mm ammonium acetate–acetonitrile (35:65, v/v) at a flow rate of 0.4 mL/min. Detection was performed by selection reaction monitoring on a triple‐quadrupole mass spectrometer following the transitions m/z 579 → 547 and 537 → 375 for sciadopitysin and internal standard, respectively, in the negative ionization mode. The calibration curve was linear from 2.90 to 1160 ng/mL for sciadopitysin. Intra‐ and inter‐day precisions were in the ranges 4.1–11.4 and 5.7–9.1% for sciadopitysin. Sciadopitysin was stable under different stability conditions. The validated assay was applied to pharmacokinetic and bioavailability studies in rats.     

Simultaneous LC–MS/MS analysis of eicosanoids and related metabolites in human serum,sputum and BALF

The differences among individual eicosanoids in eliciting different physiological and pathological responses are largely unknown because of the lack of valid and simple analytical methods for the quantification of individual eicosanoids and their metabolites in serum, sputum and bronchial alveolar lavage fluid (BALF). Therefore, a simple and sensitive LC–MS/MS method for the simultaneous quantification of 34 eicosanoids in human serum, sputum and BALF was developed and validated. This method is valid and sensitive with a limit of quantification ranging from 0.2 to 3 ng/mL for the various analytes, and has a large dynamic range (500 ng/mL) and a short run time (25 min). The intra‐ and inter‐day accuracy and precision values met the acceptance criteria according to US Food and Drug Administration guidelines. Using this method, detailed eicosanoid profiles were quantified in serum, sputum and BALF from a pilot human study. In summary, a reliable and simple LC–MS/MS method to quantify major eicosanoids and their metabolites was developed and applied to quantify eicosanoids in human various fluids, demonstrating its suitability to assess eicosanoid biomarkers in human clinical trials.     

Effect of high pressure on the nematic–isotropic transition in aerosil–liquid crystal composites

We report the first high pressure investigations of the nematic–isotropic transition in the composites of a liquid crystal compound with hydrophilic aerosil particles. The low concentrations of the aerosil particles used create soft gels of the composites. As expected T_N–Iso, the nematic–isotropic transition at room pressure exhibits a non-monotonic variation with increasing aerosil concentration. This non-monotonic behaviour is seen in the isobaric scans over the wide range of pressures studied, and its “magnitude” is dependent on the pressure applied. The surprising result of the present investigations on these nanocolloidal systems is that the slope of the pressure–temperature boundary also exhibits a non-monotonic dependence with the aerosil concentration, which qualitatively is similar to that of the transition temperature variation. Employing the transition enthalpy values determined at room pressure using differential scanning calorimetric scans collected at low heating rates, we calculate the transition volume dependence on the aerosil concentration. The study adds a new dimension, namely, the influence of pressure on liquid crystalline transitions in restricted geometries.     

Metabonomics study on the effect of Siwu Decoction for blood deficiency syndrome in rats using UPLC–Q/TOF–MS analysis

Siwu decoction (SWD), a traditional Chinese medicinal formula with over 1000 years of clinical history, is widely used for gynecological disease, especially blood deficiency syndrome, which is similar to anemia in modern medicine. In view of metabonomics being useful approach to investigate the potential mechanisms of action from the point of view of systems biology, in this study an ultra‐performance liquid chromatography–quadrupole‐time of flight mass spectrometry method was employed for a holistic evaluation of SWD on a blood‐deficiency rat model induced by N‐acetylphenylhydrazine and cyclophosphamide via plasma metabonomics study. Routine blood examination results showed that SWD could significantly improve the declining hemogram indices. Meanwhile, the plasma metabonomics profiles in different groups were analyzed and differentiating metabolites were primarily visualized through chemometric analysis. Seven biomarkers were identified in plasma samples of blood‐deficiency rat model compared with the normal group. Five main metabolism pathways were suggested using the Kyoto Encyclopedia of Genes and Genomes Pathway Analysis and Pathway Activity Profiling algorithm analysis. This indicated that SWD played a therapeu role in blood deficiency by regulating the aberrant endogenous metabolites. To sum up, this study provides clear evidence that a metabonomics study could serve as a useful tool to elucidate the systematic therapeutic profiles and mechanisms for blood deficiency syndrome of Chinese herbal medicines.     

Development of an LC–MS/MS method for quantification of two isomeric phenylpropenes and the application to pharmacokinetic studies in rats

Isomers β‐asarone and α‐asarone have recently been demonstrated to have differential pharmacological activities . Here, we report an LC–MS/MS method developed using acetonitrile to extract two isomeric phenylpropenes from rat plasma. Separation was achieved using a XDB‐C₁₈ column (100 × 2.1 mm; i.d., 1.8 μm) with a mobile phase of methanol–0.1% formic acid (55:45, v/v) at a flow rate of 0.3 mL/min. Calibration curves ranging from 5.20 to 2080 ng/mL for β‐asarone and from 3.68 to 1470 ng/mL for α‐asarone were linear (r² ≥ 0.9938) with the lower limits of quantification being 5.20 and 3.68 ng/mL for both isomers. Intravenous administration of β‐asarone (2.22 mg/kg) and α‐asarone (2.36 mg/kg) in rats yielded half‐lives of 13.40 ± 4.11 and 28.88 ± 7.82 min with clearance values of 0.196 ± 0.062 mL/min/kg and 0.112 ± 0.012 mL/min/kg for β‐asarone and α‐asarone, respectively.     

Validated LC–MS/MS method for simultaneous determination of doxorubicin and curcumin in polymeric micelles in subcellular compartments of MCF‐7/Adr cells by protein precipitation–ultrasonic breaking method

A specific and sensitive LC–MS/MS with protein precipitation– ultrasonic breaking method has been developed and validated for simultaneous determination of doxorubicin (DOX) and curcumin (Cur) in DOX and Cur co‐loaded hyaluronic acid–vitamin E succinatemicelles [(DOX + Cur)–polymeric micelles (PMs)] in subcellular compartments of resistant MCF‐7/Adr cells. Sequential extraction of four subcellular protein fractions (cytosolic, membrane/organelle, nucleic and cytoskeleton) was performed directly from MCF‐7/Adr cells after incubation with (DOX + Cur)–PMs. An ultrasonic breaking–methanol precipitation method was used for extraction of the fractions, and the micelle breaking efficiency with methanol was 98.1 and 97.6% for DOX and Cur, respectively. The analytes were analyzed using positive electrospray ionization coupled with multiple reaction monitoring. The calibration curves were linear over a concentration range of 0.5–400 ng/mL for DOX and 2–2000 ng/mL for Cur, and the recovery for the two analytes were >85% with negligible matrix effect. The intra‐day and inter‐day precision was <10.80% and relative error was within ±7.70%. The developed method was successfully applied for subcellular determination of DOX and Cur in MCF‐7/Adr cells. Moreover, Cur and (DOX + Cur)–PMs had a marked promoting effect on the distribution of DOX in the nucleic protein fraction.     

Rapid structural characterization of in vivo and in vitro metabolites of tinoridine using UHPLC–QTOF–MS/MS and in silico toxicological screening of its metabolites

Tinoridine is a nonsteroidal anti‐inflammatory drug and also has potent radical scavenger and antiperoxidative activity. However, metabolism of tinoridine has not been thoroughly investigated. To identify in vivo metabolites, the drug was administered to Sprague–Dawley rats (n = 5) at a dose of 20 mg kg^?1, and blood, urine and feces were collected at different time points up to 24 h. In vitro metabolism was delved by incubating the drug with rat liver microsomes and human liver microsomes. The metabolites were enriched by optimized sample preparation involving protein precipitation using acetonitrile, followed by solid‐phase extraction. Data processes were carried out using multiple mass defects filters to eliminate false‐positive ions. A total of 11 metabolites have been identified in urine samples including hydroxyl, dealkylated, acetylated and glucuronide metabolites; among them, some were also observed in plasma and feces samples. Only two major metabolites were formed using liver microsomal incubations. These metabolites were also observed in vivo. All the 11 metabolites, which are hitherto unknown and novel, were characterized by using ultrahigh‐performance liquid chromatography–quadrupole time‐of‐flight tandem mass spectrometry in combination with accurate mass measurements. Finally, in silico toxicological screening of all metabolites was evaluated, and two metabolites were proposed to show a certain degree of lung or liver toxicity. Copyright © 2015 John Wiley & Sons, Ltd.