Biomedical Chromatography最新文献

Glutathione (GSH), a tripeptide that consists of cysteine, glutamate and glycine, is present in all mammalian tissues in the millimolar range. Besides having numerous cellular functions, GSH is an important antioxidant and is considered a valuable biomarker in evaluating oxidative stress. This paper provides a sensitive analytical method using HPLC-ECD to quantify GSH in erythrocytes, validated using the ICH guidelines for Bioanalytical Method Validation. The sample preparation was optimised using centrifugal filtration and a hypotonic phosphate buffer for extracting GSH from erythrocytes. HPLC-ECD parameters were adjusted to allow a fast, reversed phase, isocratic separation in 10 min. The detector response was linear between 0.3 and 9.5 μg/mL with a satisfactory regression coefficient and a LOQ of 0.11 μg/mL. Intra- and inter-day repeatability ranged between 1.10% and 8.57% with recoveries ranging from 94.3% to 106.0%. Dilution integrity, benchtop, freeze-thaw and long-term stability were investigated. Samples were stable for up to 6 months at -80°C. This method has a good linear response and is repeatable, precise and accurate. It minimises GSH auto-oxidation using a centrifugal filter during sample preparation, instead of acidification. Therefore, this analytical method is suitable for quantifying GSH in erythrocytes as a marker of oxidative stress.

The DNA-dependent protein kinase (DNA-PK) is an abundant nuclear protein that mediates DNA double-strand break repair by nonhomologous end joining (NHEJ). As such, DNA-PK is critical for V(D)J recombination in lymphocytes and for survival in cells exposed to ionizing radiation and clastogens. Peposertib (M3814) is a small molecule DNA-PK inhibitor currently in preclinical and clinical development for cancer treatment. We have developed a high-performance liquid chromatography-mass spectrometry method for quantitating peposertib and its metabolite in 0.1 mL human plasma. After MTBE liquid-liquid extraction, chromatographic separation was achieved with a Phenomenex Synergi polar reverse phase (4 μm, 2 × 50 mm) column and a gradient of 0.1% formic acid in acetonitrile and water over an 8 min run time. Mass spectrometric detection was performed on an ABI SCIEX 4000 with electrospray, positive-mode ionization. The assay was linear from 10 to 3000 ng/mL for peposertib and 1-300 ng/mL for the metabolite and proved to be both accurate (97.3%-103.7%) and precise (<8.9%CV) fulfilling criteria from the Food and Drug Administration (FDA) guidance on bioanalytical method validation. This liquid chromatography-tandem mass spectroscopy (LC-MS/MS) assay will support several ongoing clinical studies by defining peposertib pharmacokinetics.

Astragali Radix (AR) is one of the famous traditional Chinese medicines (TCMs) for boosting immunity, whereas the quality markers (Q-markers) of AR have not been clearly researched. The immunomodulatory activities of the bioactive extractions and components were evaluated by NO inhibition rate; phagocytic index; IL-10, TNF-α, IL-1β, and IL-6 cytokines in RAW264.7 cells; and the relative proliferation rate of spleen cells. The total saponins (TS) and the grade 2 (Xiaoxuan, XX) of AR showed the strongest immunomodulatory activities. At the concentration of 40 μg/mL, the TS increased spleen cells proliferation by 48.0% and upregulated the level of IL-1β and IL-6. Cytokines in the XX-treated group were at least 1.6 times higher than the control group. A total of 190 common peaks were detected in AR by ultrahigh-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF-MS). The multivariate statistical analyses revealed that 41 compounds were positively correlated with immune responses, and bioactive compounds were verified by using RAW264.7 cell assay. Subsequently, the contents of six compounds in different commercial grades were determined, and the results showed the same trend in contents and activities. Finally, calycosin-7-O-β-D-glucoside, astragaloside IV, astragaloside II, astragaloside I, isomucronulatol-7-O-glucoside, and 9,10-dimethoxypterocarpan-3-O-glucoside were screened out as immunomodulatory Q-markers of AR.

Improvement of strategies to treat heart failure (HF) has been a longstanding global goal and challenge. Shen-Fu formula (SF), as a classic herbal preparation, has demonstrated efficacy in treating HF in clinical settings. However, further understanding of the therapeutic mechanisms of SF is required. In this study, metabolomics and 16S rDNA sequencing were used to analyze the effects of SF on metabolic profiling and gut microbiota in HF rats. After 4 weeks of SF treatment, the cardiac function of HF rats showed improvement, with a significant increase in ejection fraction and fractional shortening, as well as a significant decrease in left ventricular volume and mass. Metabolomics study revealed that SF regulates the levels of substances related to energy metabolism, primarily involving lysophosphatidylcholines and polyunsaturated fatty acids. In addition, we found that SF regulates the structure of the microbial community in HF rats and modulates the balance between probiotic and pathogenic bacteria. Furthermore, the SF combination exhibited a superior effect that was better than the use of each herb separately. These results demonstrate the potential of SF therapy in the management of HF and highlight the role of SF in regulating fatty acid metabolism and gut microbiome during HF.

To facilitate clinical therapeutic drug monitoring (TDM) of polymyxin B (PB) and polymyxin E (PE), we developed and validated a simple LC-MS/MS method for simultaneous determination of PB (including polymyxin B1 (PB1), polymyxin B2 (PB2), polymyxin B3 (PB3) and isoleucine-polymyxin B1 (ile-PB1)) and PE (including polymyxin E1 (PE1) and polymyxin E2 (PE2)) in human plasma. PB or PE was extracted from 20.0 μL plasma using a 5% (v/v) formic acid acetonitrile solution and separated on a BEH-C18 column (2.1 × 100 mm, 1.7 μm) with a mobile phase consisting of 0.8% formic acid aqueous solution and 0.2% formic acid acetonitrile solution. Gradient elution was performed over 5.5 min at a flow rate of 0.250 mL/min. Quantitative analysis was conducted in positive ion scanning mode by electrospray ionization and multiple reaction monitoring. The method validation was conducted based on bioanalytical method validation guidance, including specificity, calibration curve, precision, accuracy, recovery, matrix effect, stability and dilution integrity and all of the results satisfied the requirements. The method was simple, robust and high-throughput and is currently being used to provide a TDM service to enhancing therapeutic efficacy and safety use of the PB and PE.

A sensitive and simple method using ultra-liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated to determine the concentration of curcumin in rat plasma and tissue samples. Emodin was selected as the internal standard (IS), and biological samples were pretreated with simple one-step acetonitrile precipitation. The calibration curves exhibited linearity within the range of 1-1000 ng/ml for both rat plasma and tissue samples. The accuracy and precision of intra-day as well as inter-day determinations ranged from 99.3% to 117.3% and from 98.2% to 105.1%, respectively. This method demonstrated excellent recovery rates ranging from 76.4% to 96.4% along with minimal matrix effect ranging from 86.5% to 99.6%. The effectiveness of this method was successfully demonstrated through its application in an in vivo pharmacokinetic and tissue distribution study after single administration via inhalation (100 mg/kg), oral gavage (100 mg/kg) and intravenous injection (2.5 mg/kg) of curcumin in rats. The results revealed that inhalation significantly improved the bioavailability of curcumin, with most of the drug being deposited in the lung. These findings highlight inhalation as an effective route for targeted delivery of drugs directly into lung tissues, thus suggesting potential future applications for treating pulmonary diseases utilizing inhaled curcumin.

Nimbolide is a major furanoid compound isolated from Azadirachta indica. The aim of this study was to characterize the metabolites of nimbolide in rats and to propose the metabolic pathways. The metabolites were generated by incubating nimbolide (10 μM) with rat liver microsomes, nicotinamide adenine dinucleotide phosphate (NADPH), and nucleophiles (glutathione [GSH] or N-acetyl-lysine [NAL]) at 37°C for 60 min. For the in vivo study, nimbolide was intravenously administered to rats at a single dose of 10 mg/kg, and the bile and urine were collected. The metabolites were identified by ultra-high-performance liquid chromatography-quadrupole/orbitrap mass spectrometry (UPLC-Q/Orbitrap-MS) using electrospray ionization in positive ion mode. Totally, nine metabolites were detected, and their identities were characterized by accurate MS and MS/MS data. In GSH-supplemented liver microsomes, GSH conjugation was the primary elimination pathway. The furan ring was bioactivated into cis-butene-1,4-dial that can be trapped by GSH. In NAL-supplemented liver microsomes, two NAL conjugates (M4 and M5) derived from cis-butene-1,4-dial were observed. In rat bile and urine, N-acetyl-cysteine, cysteine-glycine, and GSH conjugate were also found. The current study provides an overview of the metabolism and the bioactivation profiles of nimbolide in rats, which aids in understanding its safety and activity.

The synthesis of optically active compounds requires determination of ee, er, and enantiomeric purity. The aim of the present paper is to review the synthesis of several chiral derivatizing reagents (CDRs) in a rational manner, which were successful for the separation and isolation of enantiomers of a variety of active pharmaceutical ingredients and other important and useful racemates. Besides, the application of (i) certain enantiomerically pure amines, either directly or by incorporating each of them as chiral auxiliary in difluorodinitrobenzene or cyanuric chloride moieties to construct the CDR, (ii) (S)-ketoprofen and (S)-levofloxacin as chiral platforms, and (iii) a few isothiocyanates, have been suitably included. Attention is drawn to the use of water micellar mobile phase as the "green" RP-HPLC method and the use of simple achiral derivatization with ninhydrin, particularly. Synthesis of CDRs and their application for enantioseparation of racemates and detagging of certain chromophoric reagent components for obtaining native enantiomers are other interesting features included herein. The methods can be easily used to determine and control enantiomeric purity with advantages over a variety of commercial chiral phases. This comprehensive review not only highlights innovative methodologies for enantioseparation but also underscores their practical applications in controlling and ensuring the enantiomeric purity of pharmaceutical compounds.

Trichosanthes kirilowii-Allium macrostemon (Chinese name Gualou and Xiebai, GLXB), a classical herb pair, has significant clinical efficacy in the treatment of myocardial ischemia (MI). In this study, network pharmacology combined with RNA-seq strategy was employed to predict the targets and pathways of GLXB for MI. GLXB significantly modulated signaling pathways related to the pathology of MI, such as anti-inflammatory and anti-apoptotic signaling pathways such as WNT, PI3K/AKT, and AMPK. GSEA showed that GLXB administration downregulated these key pathways. In addition, Metabolomic analysis demonstrated that GLXB treatment reversed metabolic disorder. Integrative analysis demonstrated three key metabolites (pyruvate, lactate, and palmitate) and three differential genes (Pck1, Cdo1, and Cth) that affected glycolysis or gluconeogenesis and cysteine and methionine metabolism. The results of molecular docking showed that chrysin-7-O-glucuronide and diosmetin-7-O-rutinoside may be the crucial components that exert myocardial protective activity. Western blot showed that GLXB administration reversed the expression levels of Pck1, Cdo1, Cth, Alb, Bcl2, and Ccnd1. This study has elucidated that GLXB could alleviate MI in rats by modulating WNT and PI3K/AKT signaling pathways, thereby reducing inflammation and apoptosis as well as improving energy metabolism.

TLC is used globally, yet less attention has been paid to TLC (in enantioseparation) despite its advantages. The present paper describes/reviews successfully practiced direct approaches of 'chiral additive in achiral stationary phase' (as an application of in-home thought out, prepared, tested, and modified chiral stationary phase), 'pre-mixing of chiral reagent with the enantiomeric mixture' (an approach using both achiral phases during chromatographic separation) and 'chiral additive in mobile phase', and chiral ligand exchange for enantioseparation of DL-amino acids, their derivatives, and some active pharmaceutical ingredients. It provided efficient enantioseparation, quantitative determination, and isolation of native forms via in-situ formation of non-covalent diastereomeric pair. The mechanism of enantioseparation in these approaches has been discussed along with the isolation and establishment of the structure of diastereomers. This may help chemists gain useful insights into fields outside their specialization and the experts get brief accounts of recent key developments, providing solutions for sustainable development of less expensive methods for control of enantiomeric purity and isolation of native enantiomers.