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Study on the drug–drug interaction of antituberculosis drugs — PA-824 and moxifloxacin based on pharmacokinetics in rats by LC–MS/MS

Jing Juan, Jia Yuting, Feng Tian, Xie Tian, Li Zhoupeng, Hao Yong, Wang Libin

Acta Chromatographica

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2019

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Vol. 31, no. 3

206--210

EN

A simple, rapid, and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for the simultaneous quantitation of PA-824 and moxifloxacin in rat plasma using carbamazepine as an internal standard (IS). The sample preparation involved a one-step protein precipitation method with methanol. The separation was performed on Inertsil® ODS3 C18 column (150 mm × 4.6 mm, 5 μm) and maintained at 30 °C. The mobile phase consisted of 0.1% formic acid in acetonitrile–water (90:10 v/v) with fast isocratic elution at a flow rate of 0.6 mL/min and a run time of 10 min. A mass spectrometer was run in the positive ion electrospray ionization (ESI) mode using multiple reaction monitoring (MRM) to monitor the mass transitions. The MRM transitions were chosen to be m/z 360.1 → m/z 175.0 for PA-824, m/z 402.0 → m/z 383.9 for moxifloxacin, and m/z 237.1 → m/z 194.0 for IS. The method was fully validated in terms of selectivity, linearity, accuracy, precision, matrix effect, recovery, and stability, respectively. The method was successfully applied to drug–drug interaction (DDI) study of PA-824 and moxifloxacin in rats. The results show that the main pharmacokinetic parameters of PA-824, namely, Tmax, t1/2, and AUC(0–t), increased more in the PA-824 and moxifloxacin group than in the PA-824 group. However, there were little changes in the main pharmacokinetic parameters of moxifloxacin from single and combined groups.

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Simultaneous determination of levocetirizine dihydrochloride and montelukast sodium in human plasma by LC–MS/MS: development, validation, and application to a human pharmacokinetic study

Rashed Noha Salem, Nasr Zeinab Adel

Acta Chromatographica

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2019

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Vol. 31, no. 3

194--200

EN

Objectives: A simple, rapid, selective, and sensitive high-performance liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed for the simultaneous determination of levocetirizine dihydrochloride and montelukast sodium in human plasma using fexofenadine hydrochloride as an internal standard. Method: Liquid–liquid extraction of both drugs and internal standard from plasma into ethyl acetate was used for sample preparation and analysis. Separation of both drugs and internal standard was achieved on an Inertsil ODS-3 (4.6 mm × 50 cm, dp 5 μm, particle size) column using an isocratic mobile phase of acetonitrile and 10 mM ammonium formate adjusted to pH 8 with 50 μL ammonium hydroxide in composition of 73:27 (v/v) at a flow rate of 0.7 mL/min. The LC–MS/MS was operated under the multiple reaction monitoring mode (MRM) using an electrospray ionization technique. Mass parameters were optimized to monitor transitions at m/z [M + H]+ 389.0 → 200.8 for levocetirizine dihydrochloride, m/z [M + H]+ 586.2 → 422.2 for montelukast sodium, and m/z [M + H]+ 502.2 → 466.0 for fexofenadine hydrochloride. Results: The method was found to be linear in the range of 1–500 ng/mL for both drugs. The intra-day and inter-day precision were in the range of 0.96–1.92% and 1.03–1.55%, respectively. Matrix effect was acceptable with %RSD < 15. Conclusion: The proposed method was validated and successfully applied for a pharmacokinetic study of both drugs in human plasma after oral administration of their pharmaceutical preparation.

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Determination of polyoxin B in cucumber and soil using liquid chromatography tandem mass spectrometry coupled with a modified QuEChERS method

Song Shiming, Chen Zhaojie, Wei Jie, Lei Yuhao, Deng Cheng, Tan Huihua, Li Xuesheng

Acta Chromatographica

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2019

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Vol. 31, no. 2

157--163

EN

A sensitive and effective method based on a modified QuECHERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of polyoxin B in cucumber and soil using liquid chromatography tandem–mass spectrometry (LC–MS/MS) was developed and validated. Samples were extracted using 1% formic acid in ultrapure water and purified via reversed-dispersive solid phase extraction (r-dSPE) using C18. Recovery of polyoxin B ranged from 83.0% to 112.1% with relative standard deviation (RSD) (n = 5) of 3.0–5.2%. The limit of quantification (LOQ) and the limit of detection (LOD) were 0.01 and 0.003 mg/kg for cucumber and soil, respectively. The method was subsequently applied for real sample analysis. The dissipation experiments showed that half-lives of polyoxin B in cucumber and soil were 2.5–5.0 days. The terminal residues of polyoxin B at preharvest intervals (PHIs) of 3 days and 5 days in cucumber were less than 0.05 mg/kg. We therefore suggest that the developed method can be extrapolated to other agricultural crops or food for routine analysis. It also can be used to determine the PHIs. Moreover, these results will aid in establishing the maximum residue limit (MRL) for cucumber in China.

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Development and validation of liquid chromatography–tandem mass spectrometry method for simultaneous determination of zinc pyrithione and pyrithione in shampoos

Kim T. H., Jung G. H., Lee E. H., Park H. R., Lee J. K., Kim H. G.

Acta Chromatographica

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2018

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Vol. 30, no. 3

200--205

EN

A simple, rapid, and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for the determination of zinc pyrithione (ZnPT) and pyrithione (PT) in shampoos. The method consisted of a liquid–liquid extraction for sample preparation. The mass spectrometer was operated in multiple reaction monitoring (MRM) mode via the positive electrospray ionization interface. A linear regression (weighted 1/x) was used to fit calibration curves over the concentration range of 50–2000 ng/mL for both ZnPT and PT. Excellent linearity (r 2 ≥ 0.9996) was achieved for all. The method was validated and found to be accurate (95.9–108.2% for ZnPT and 94.9–110.4% for PT), precise, and selective. Analytes in shampoos were found to be stable in the autosampler (6 °C for 6 h), in room temperature (for 6 h), and after three freeze–thaw cycles, and recovery of analytes was reproducible (90.8–94.6% for ZnPT and 90.2–96.3% for PT).

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Pharmacokinetic studies of phloretin in beagle dogs plasma using LC–MS/MS

Libin W., Le M., Tian F., Xueying L., Shengyong Z.

Acta Chromatographica

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2017

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Vol. 29, no. 4

443--447

EN

A simple, sensitive, and rapid liquid chromatography–tandem mass spectrometry (LC–MS/MS) method has been developed and validated for determination of phloretin in dog plasma using darunavir as internal standard. The phloretin was separated by the Inertsil® ODS3 C18 column (150 mm × 4.6 mm, 5 μm) and determined by LC–MS/MS. The electrospray ionization (ESI) source was operated in negative ionization mode for phloretin and positive ionization mode for darunavir (internal standard, IS). The multiple reaction monitoring (MRM) transitions were chosen to be m/z 273.0 → m/z 148.9 for phloretin, m/z 443.2 → m/z 401.0 for 2′,4′,6′,4-tetra-acetylphloretin and m/z 548.1 → m/z 69.1 for IS. The method was validated for accuracy, precision, linearity, range, selectivity, lower limit of quantification (LLOQ), recovery, and matrix effect. All validation parameters met the acceptance criteria according to regulatory guidelines. 2′,4′,6′,4-Tetra-acetylphloretin, as a prodrug of phloretin, is more stable than phloretin (PH) in vitro, protecting phenolic hydroxy from being oxygenated. The method had been successfully applied to a pharmacokinetic study of administration of phloretin and 2′,4′,6′,4-tetra-acetylphloretin in beagle dogs. Significant differences of tmax, Cmax, and area under the plasma concentration curve (AUC) were observed between phloretin and 2′,4′,6′,4-tetra-acetylphloretin.

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A validated HPLC–MS/MS method for the quantification of supinoxin in rat plasma and its application to pharmacokinetic study

Jeong J.-W., Seol Y.-H., Hyun H.-Ch., Kim H.-R., Lee J.-H., Gong Y.-D., Kang N.-S., Koo T.-S.

Acta Chromatographica

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2017

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Vol. 29, no. 4

463--468

EN

A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed for the quantification of an anticancer drug, supinoxin (RX-5902), in rat plasma. Following precipitation pretreatment using 0.1% formic acid in acetonitrile, separation was performed using a reverse phase liquid chromatography column packed with C18 (3.5 μm, 2.1 × 50 mm) along with a mobile phase of 0.1% formic acid in distilled water and 0.1% formic acid in acetonitrile at a flow rate of 0.3 mL min-1. Detection was achieved using MS/MS by multiple reaction monitoring via an electrospray ionization source at mass/charge transitions of m/z 442.30 → 223.30 for supinoxin and m/z 430.08 → 223.20 for the internal standard DGG-200064. This method demonstrated a linear standard curve (r = 0.9980) over a supinoxin concentration range of 0.0005–1 μg Ml-1, as well as intra- and inter-assay precisions below 7.08% and 13.74%, respectively, and an accuracy of 1.15–4.50%. The matrix effect, recovery, and process efficiency were 93.63%, 99.70%, and 93.33%, respectively. Thus, a sensitive and reliable LC–MS/MS method was developed and validated for the quantification of supinoxin in rat plasma. This method was successfully applied to the evaluation of pharmacokinetic studies after single intravenous and oral administration of 1 mg kg-1 supinoxin in rats.

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Determination of antibiotic residues in southern Baltic Sea sediments using tandem solid-phase extraction and liquid chromatography coupled with tandem mass spectrometry

Siedlewicz G., Borecka M., Białk-Bielińska A., Sikora K., Stepnowski P., Pazdro K.

Oceanologia

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2016

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No. 58 (3)

221--234

EN

The main objective of this study was to adapt analytical procedures for determining antibiotic residues in solid and aquatic samples to marine sediments and to investigate the occurrence of 9 sulfonamides, trimethoprim and 2 quinolones in southern Baltic Sea sediments. The analytical procedure was applied to sediment samples characterized as sand and silty sand. The validation results showed that a sensitive and efficient method applying tandem solid-phase extraction (SPE) and liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) was obtained. Analytes were determined in the lower ng g−1 range with good accuracy and precision. The proposed analytical procedure was applied to the analysis of 13 sediment samples collected from the Baltic Sea along the Polish coast. Concentrations of antibiotic residues in environmental samples were calculated based on external matrix-matched calibration. Residues of nine out of twelve of the above antibiotics were detected in sediment samples in a concentrations of up to 419.2 ng g−1 d.w. (dry weight). Sulfamethoxazole and sulfachloropyridazine were the most frequently detected compounds (58% of the analyzed samples). The occurrence frequency of trimethoprim was 42% and it was always detected simultaneously with sulfamethoxazole. Preliminary studies on the spatial distribution of the analyzed antibiotics indicate a high level of antibiotics occurring in the Pomeranian Bay and close to the mouths of Polish rivers. The study is the first one to demonstrate the occurrence of antibiotic residues in sediments of the Polish coastal area. The obtained results suggest that sediment can be an important secondary source of antibiotic residues in the marine environment.

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LC—MS/MS Studies for the Identification and Characterization of Degradation Products of Fenofibrate and Their Degradation Pathways

Mulgund S. V., Anbazhegan S., Gabhe S. Y.

Acta Chromatographica

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2016

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Vol. 28, no. 2

159--173

EN

In the present study, the degradation behavior of Fenofibrate under different International Conference on Harmonization (ICH) suggested conditions was studied. Characterization of degradation products by liquid chromatography–tandem mass spectrometry (LC–MS/MS) studies in solution form was done, and the possible mechanism for the formation of degradants is discussed. Fenofibrate was subjected to different hydrolytic stress conditions and thermal stress condition (in solid form). Successful separation of drug from degradants was achieved on a C18 column using water–acetonitrile (25:75 v/v) as the mobile phase. Other high-performance liquid chromatography (HPLC) parameters were: flow rate, 1 mL min−1; detection wavelength, 286 nm; column temperature, 25 °C; and injection volume, 20 μL. The method was validated for linearity, precision, accuracy, robustness, and specificity and was stability-indicating one, based on the specificity studies. The drug degraded under acidic, basic, and oxidative hydrolytic stress while it was relatively stable towards neutral hydrolysis and thermal stress. The stressed samples were subjected to LC–MS/MS analysis. On the basis of spectral data, the structures of four degradation products and one interaction product were suggested. Degradation products were characterized to be isopropyl acetate, 2-[4-(4-chlorobenzoyl)phenoxy]-2-methyl propanoic acid, 4-hydroxy benzoic acid, and benzoic acid. The structure of one interaction product was proposed as methyl 2-[4-(4-chlorobenzoyl)phenoxy]-2-methylpropanoate.