Authors:A. Kumar, R.K. Dubey, K. Kant, D. Sasmal, M. Ghosh, and N. Sharma
Deltamethrin, a well-known type 2 synthetic pyrethroid insecticide, is a widespread environmental toxicant. It has potential to accumulate in body fluids and tissues due to its lipophilic characteristics. The immune system is among the most sensitive targets regarding toxicity of environmental pollutants. Various methods are available in the literature to analyze deltamethrin (DLM) concentration in plasma and tissues, but regarding the immune organs, only one gas chromatography–tandem mass spectrometry (GC–MS/MS) method (on spleen tissues) has been reported. In the present investigation, a rapid and sensitive high-performance liquid chromatography (HPLC) method has been developed and validated to determine DLM concentration in plasma, thymus, and spleen using zaleplone as an internal standard. Liquid chromatography (LC) separation is performed on an Agilent Zorbax® C8 column (250 mm × 4.6 mm, i.d., 5 μm) with isocratic elution using a mobile phase consisting of acetonitrile–5 mM KH2PO4 (70:30, v/v) at a flow rate of 1 mL min−1. The lower limit of quantification (LLOQ) for DLM is 10 ng mL−1 (plasma, thymus, and spleen). The method has been validated in terms of establishing linearity, specificity, sensitivity, recovery, accuracy, and precision (intra- and inter-day) and stabilities study. This validated method was successfully applied to a pharmacokinetic and tissue distribution study of DLM in mice.
Authors:M. Nurul Islam, F. Downey, and C. K.-Y. Ng
Scutellaria L. is a diverse genus of the Lamiaceae (Labiatae) family of over 300 herbaceous plants commonly known as skullcaps. Various species of Scutellaria are used as ethnobotanical herbs for the treatment of ailments like cancer, jaundice, cirrhosis, anxiety, and nervous disorders. Scutellaria incana L., commonly known as the Hoary skullcap, is a traditional medicinal plant used by native Americans as a sedative for nervousness or anxiety. S. incana metabolites were identified by comparing their high-performance liquid chromatography (HPLC) retention times and mass spectra with those of the corresponding authentic standards. Where standards were unavailable, the structures were characterized on the basis of their tandem mass spectrometry (MS/MS) spectra following collision-induced dissociation (CID) and the accurate masses of the corresponding deprotonated molecules [M-H]− (mass accuracy ± 5 ppm). A total of 40 flavonoids, including two phenolic glycosides, were identified from leaves, stems, and roots of S. incana. Differences in the flavonoid composition between leaves, stems, and roots in S. incana were observed although the flavonoid profile of S. incana is consistent with other Scutellaria species. Further work should focus on assessing the potential of S. incana as a source of these bioactive metabolites.
Authors:A. Kwiecień, K. Piątek, P. Żmudzki, and J. Krzek
A simple, selective, and sensitive thin-layer chromatographic—densitometric method has been developed for the determination of sulfasalazine besides its possible impurities in pharmaceutical preparations. The mobile phase was composed of ethyl acetate—methanol—ammonia 25% 10:7:3 (υ/υ/υ), and the stationary phase was aluminum plates precoated with silica gel 60 F254 that enabled to obtain well resolved peaks of sulfasalazine and its impurities. The developed chromatograms were analyzed densitometrically at λ = 360 nm. RF values and ultraviolet (UV) spectra were used to identify the compounds. The developed method is highly sensitive (limit of detection [LOD] = 17.11 ng spot−1, limit of quantitation [LOQ] = 51.84 ng spot−1), precise (relative standard deviation [RSD] = 1.43%–4.28%), and accurate (RSD = 1.64%–4.27%). The linearity of the method was checked within the range 20–120 ng spot−1. The method was successfully applied for the determination of sulfasalazine in pharmaceutical preparations besides its impurities. The structures of impurities present in the standard substance and in pharmaceutical preparations were established by ultra-performance liquid chromatography—tandem mass spectrometry (UPLC—MS/MS) technique.
Authors:Yan-Mei Zhong, Xun-Long Zhong, Ji-Hua Wang, and Liang Han
Patrinia scabiosaefolia Fisch. (PSF), a well-known traditional Chinese medicine, has been demonstrated to show therapeutic effects on inflammatory bowel disease. In this study, a rapid and sensitive method using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was developed for identification of the major constituents in PSF. The separation analysis was performed on Waters Acquity UPLC system, and the accurate mass of molecules and their fragment ions were determined by Q-TOF-MS. Thirty-one constituents, including triterpenoids, iridoids, flavonoids, and organic acids were detected and tentatively deduced on the basis of their element compositions, tandem mass spectrometry (MS/MS) data, and relevant literatures. Twelve constituents were discovered for the first time in PSF. The results demonstrated that hederagenin-type and oleanolic acid-type saponins were the main constituents of PSF. Our work provides a certain foundation for further quantitation of major chemical constituents and in vivo pharmacokinetic studies of PSF. Moreover, the analytical approach developed herein has proven to be generally applicable for profiling the chemical constituents in traditional Chinese medicines (TCMs) and other complicated mixtures.
Authors:J. Kuc, A. Grochowalski, S. Mach, and D. Placha
This paper is focused on the determination of three hexabromocyclododecane isomers, α, β, and γ, in the tissue of the most commonly consumed marine and farmed fish in Central Europe. The analytical procedure contains multiple steps: extraction, dialysis using semipermeable membranes, and a clean-up step using a silica gel column. Hexabromocyclododecane (HBCD) isomers were determined by sensitive isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method which is characterized by a low limit of detection (1 pg g−1 fresh weight). The recovery values obtained for individual isomers were in the range of 89–124%. The γ-HBCD isomer was detected in all samples. This isomer also had the largest percentage in comparison with the other isomers, except in salmon, in which the α-HBCD isomer was more abundant. The highest level of total HBCD was measured in mackerel (650 ± 195 pg g−1 fresh weight). Cluster analysis allowed the differentiation of groups of objects and the display of objects based on the degree of integration within the same group. Spearman’s rank correlation indicated no statistically significant difference between the levels of HBCD and the fat content in the fish samples.
Authors:Su-su Bao, Jian Wen, Teng-hui Liu, Bo-wen Zhang, Chen-chen Wang, and Guo-xin Hu
Olmutinib (Olita™) is an oral third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) which is used to treat non-small cell lung cancer (NSCLC). A simple, rapid, and sensitive method based on ultra-performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) has been developed for the determination of olmutinib. Sample preparation was performed following simple one-step protein precipitation with acetonitrile. Olmutinib and internal standard (dasatinib) were separated on an Eclipse Plus C18 RRHD (2.1 × 50 mm, 1.8 μm) column. The mobile phase consisted of acetonitrile–0.1% formic acid in water with gradient elution. A total run time of 1.7 min was achieved. Detection was performed on a positive-ion electrospray ionization mass spectrometer in multiple reaction monitoring (MRM) mode, using transitions of m/z 487.2 → 402.1 for olmutinib and m/z 488.2 → 401 for dasatinib (IS), respectively. The calibration curve (R2 = 0.999) was linear over the range of 1–500 ng/mL. The recovery of olmutinib ranged from 85.8% to 95.5%. This method can be applied to pharmacokinetic studies of olmutinib.
Authors:L. Vlase, D.-S. Popa, A. Tero-Vescan, and N. Olah
A new liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for the quantification of seven isoflavones (daidzin, genistin, ononin, daidzein, glycitein, genistein, and formononetin) and coumestrol in vegetable extracts was developed. The separation was performed on a Zorbax SB-C18 column with a mixture of methanol (solvent A) and 0.1% (υ/υ) acetic acid in water (solvent B) under gradient conditions at 50°C with a flow rate of 1 mL min−1. The detection of analytes was performed by electrospray ionization, negative ionisation, in non-reactive MS2 mode for aglycons or in reactive MS2 mode for glycosides. The method shows a good linearity (r2 > 0.9948) over the concentration range of 40–4000 ng mL−1 for all analytes, a good precision (CV < 11%) and accuracy (<10%). The method was successfully applied to quantify the isoflavones and coumestrol in vegetable extracts obtained from red clover (Trifolium pratense L., Fabaceae) and dyer's greenweed (Genista tinctoria L., Fabaceae) and can be used in the chemical characterization of vegetables with phytoestrogen content.
Authors:Sinan Zazoğlu, Beril Anilanmert, Muhammed Aydin, and Salih Cengiz
A fast, reliable, inexpensive, and practical method with a low determination limit and high recovery has been developed for the determination of the marijuana metabolite in routine analysis. THC-COOH in urine was validated using liquid chromatography—tandem mass spectrometry (LC—MS/MS). Before an easy single-step extraction with Toxi-Tubes, basic hydrolysis was performed at 60 °C for 30 min. LC—MS/MS analysis takes 2.5 min for each sample, and the retention time of the analyte is 1.75 min. Specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, repeatability, and intermediate precision (inter-day) system suitability parameters were determined in the validation study. The recovery of the extraction method was 88.67 (±5.91). LOD and LOQ values were 1.41 and 5.00 ng mL−1, respectively. The method showed linear response between the values 5.00 and 500.00 ng mL−1. The repeatability was 9.64% (relative standard deviation, RSD%), and the intermediate precisions (RSDR%) were 10.73%, 13.74%, and 8.11% at 10.00, 100.00, and 200.00 ng mL−1 concentration levels, respectively. No statistically significant difference was found in ANOVA analysis, between three consecutive days in intermediate precision study, for 90% confidence level. HorRat values were between 0.34 and 0.61. The method was applied to CEDIA positive samples, obtained from the Trabzon Group Presidency of Turkish Council of Forensic Medicine, successfully.
The composition and concentration of natural products largely depend on a plant part, development stage, cultivar, and growing conditions. This study evaluated the influence of cultivars and production systems on the composition of natural products (benzoxazinoids) in wheat aerial parts. The determination of benzoxazinoids was performed by combining pressurized liquid extraction, ultra-performance liquid chromatography, and tandem mass spectrometry. Six benzoxazinoids were identified and quantitated in wheat varieties. Significant differences were observed among the examined varieties. The average concentrations of total researched compounds were definitely higher in the organically produced spring wheat cultivars than in the winter ones. The content of these compounds in the same varieties grown under organic and conventional systems showed their higher content under the organic one. The main benzoxazinoids detected in wheat varieties were 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside (DIMBOA-Glc) and 6-methoxy-2-benzoxazolinone (MBOA). The richest sources of benzoxazinoids were Brawura, Łagwa, and Kandela (52.46, 34.67, and 30.14 μg/g dry weight [DW], respectively).
Authors:S. Thomas, S. K. Paul, A. Agarwal, and C. S. Mathela
Galantamine hydrobromide was subjected to oxidative stress degradation using hydrogen peroxide and analyzed as per the chromatographic conditions described in European Pharmacopoeia. The drug showed considerable degradation at ambient temperature resulting in the formation of two degradation products at relative retention times (RRTs) 0.63 and 2.52. The minor degradant at RRT 0.63 was identified as galantamine N-oxide. The principal degradant formed at RRT 2.52 was found to be unknown and has not been reported previously. The unknown impurity was identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) followed by isolation using semi-preparative high-performance liquid chromatography (HPLC). The isolated impurity was characterized using one-dimensional, two-dimensional nuclear magnetic resonance spectroscopy (1D and 2D NMR) and elemental analysis (EA). The principal degradant was found to be formed due to the generation of bromine and subsequent attack on the aromatic ring via in situ reaction between hydrogen bromide and hydrogen peroxide. The unknown impurity was characterized as (4aS,6R,8aS)-5,6,9,10,11,12-hexahydro-1-bromo-3-methoxy-11-methyl-4aH-benzofuro [3a,3,2-ef]  benzazepin-6-ol.