LC-MS/MS Application in Pharmacotoxicological Field: Current State and New Applications

Development of a UHPLC-MS/MS method for the quantification of Pristinamycin ⅠA and ⅡA in beagle dog plasma and its pharmacokinetic application

The aim of this study was to develop and fully validate a sensitive and rapid ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous quantification of pristinamycin ⅠA (PⅠA) and pristinamycin ⅡA (PⅡA) in plasma of beagle dogs after oral administration of pristinamycin tablets. PⅠA, PⅡA and quinupristin (internal standard, IS) were separated on an Agilent Eclipse Plus C18 column (2.1 mm × 100 mm, 3.5 μm particle size) by using gradient elution consisting of methanol and water (0.1 % formic acid) at a flow rate of 0.4 mL/min in 4.0 min. Multiple reaction monitoring (MRM) mode was performed to quantify data under monitoring precursor-product ion transitions of m/z 867.6→134.1, 548.4→287.1 and 1022.7→133.9 for PⅠA, PⅡA and IS at positive ion mode, respectively. The method was developed at linearity ranging from 1.0 to 1000 ng/mL for all analytes.The accuracy of PⅠA and PⅡA was observed to range between -10.6 % and 7.1 %, while the precision was found to be within 8.9 %. No significant matrix effect was observed. PⅠA and PⅡA demonstrated stability during sample storage, preparation and analytic procedures. Furthermore, this method was successfully applied in the investigation of the pharmacokinetic profile of PⅠA and PⅡA in beagle dogs after oral administration of pristinamycin tablets (75 mg for PⅠA and 175 mg for PⅡA). The biological half-life (t1/2) was determined to be 1.75 ± 0.07 h and 1.44 ± 0.31 h for PⅠA and PⅡA, respectively. The areas under curves (AUC0-t) of PⅠA and PⅡA were 80.7 ± 24.6 and 230 ± 94.8 μg/L·h, respectively.

Rapid on-site detection of illicit drugs in urine using C18 pipette-tip based solid-phase extraction coupled with a miniaturized mass spectrometer

Drug abuse is a social issue worldwide, and there is an increasing demand for on-site rapid detection of illicit drugs. In this study, a rapid and simple analytical method for the detection of 6-monoacetylmorphine (6-MAM), methamphetamine (MA), methylenedioxymethamphetamine (MDMA), ketamine (K), norketamine (NK), and cocaine (COC) in urine was developed. The developed method combines C18 pipette-tip based solid-phase extraction (C18 PT-SPE) with a miniaturized mass spectrometer (miniMS), exhibiting remarkable simplicity, high sensitivity, and strong reliability, compared with the conventional method. The optimal extraction and elution conditions for C18 PT-SPE were considered as 9 and 3 aspirating-dispensing cycles, respectively. The miniMS parameters including spray voltage, isolation potential, and collision-induced dissociation energy for the detection of these six illicit drugs were optimized using a nano-electrospray ionization method. The limit of detection (LOD), limit of quantification (LOQ), linear range, and linearity for the analysis of six illicit drugs in urine with the proposed C18 PT-SPE-miniMS method were determined. Except for the LOD of K and COC was determined as 0.5 and 0.25 ng mL-1 respectively, and the LOD of 6-MAM MA, MDMA, and NK was determined as 1 ng mL-1. This method enables rapid on-site detection, providing easier operation, lower cost, and better portability compared to conventional methods, making it a potential tool in drug crime investigation and forensic science.

Multi-omics combined to explore the purging mechanism of Rhei Radix et Rhizoma and Magnoliae Officinalis Cortex

Rhei Radix et Rhizoma and Magnoliae Officinalis Cortex have been used together to treat constipation in the clinical practices for more than 2000 years. Nonetheless, their compatibility mechanism is still unclear. In this study, the amelioration of Rhei Radix et Rhizoma combined with Magnoliae Officinalis Cortex on constipation was systematically and comprehensively evaluated. The results showed that their compatibility could markedly shorten gastrointestinal transport time, increase fecal water content and frequency of defecation, improve gastrointestinal hormone disorders and protect colon tissue of constipation rats compared with the single drug. Furthermore, according to 16S rRNA sequencing in conjunction with UPLC-Q-TOF/MS, the combination of two herbal medications could greatly raise the number of salutary bacteria (Lachnospiraceae, Romboutsia and Subdoligranulum) while decreasing the abundance of pathogenic bacteria (Erysipelatoclostridiaceae). And two herb drugs could markedly improve the disorder of fecal metabolic profiles. A total of 7 different metabolites associated with constipation were remarkably shifted by the compatibility of two herbs, which were mainly related to arachidonic acid metabolism, alpha-linolenic acid metabolism, unsaturated fatty acid biosynthesis and other metabolic ways. Thus, the regulation of intestinal microbiome and its metabolism could be a potential target for Rhei Radix et Rhizoma and Magnoliae Officinalis Cortex herb pair to treat constipation. Furthermore, the multi-omics approach utilized in this study, which integrated the microbiome and metabolome, had potential for investigating the mechanism of traditional Chinese medicines.

UPLC-MS/MS-Based Target Screening of 90 Phosphodiesterase Type 5 Inhibitors in 5 Dietary Supplements

The aim of individuals consuming health supplements is to attain a robust state through nutritional regulation. However, some unscrupulous manufacturers, motivated by profit, fraudulently incorporate drugs or unauthorized components with therapeutic effects into the product for instant product performance enhancement. The long-term use of these products may inadvertently inflict harm on human health and fail to promote nutritive healthcare. The illegal inclusion of these substances is prevalent in kidney-tonifying and sexuality-enhancing products. Developing effective analytical methods to identify these products and screen for illegal added ingredients can effectively prevent such products from reaching and remaining on the market. A target screening method for the detection and quantification of 90 phosphodiesterase type 5 inhibitors (PDE-5is) in 5 kinds of health products was developed and validated. The type of dietary supplements varied from tablets, capsules, and protein powder to wine and beverages. Sample preparation was completed with a one-step liquid phase extraction. The screening process of 90 PDE-5is was done efficiently within 25 min by ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) using the dynamic multiple reaction monitoring (dMRM) technique. The LODs of 90 PDE-5is were detected at levels ranging from 25 to 85 ng/g or ng/mL. This novel targeting methodology was effective and can be applied to routine market supervision. Among 286 batches of samples, 8 batches were found to be positive. Three kinds of PDE-5is were first detected in healthy products. The screening method demonstrated herein will be a promising and powerful tool for rapid screening of PDE-5is.

Positive In Vitro Effect of ROCK Pathway Inhibitor Y-27632 on Qualitative Characteristics of Goat Sperm Stored at Low Temperatures

Y-27632, as a cytoskeleton protector, is commonly used for low-temperature preservation of cells. Goat sperm are prone to damage to the cytoskeleton under low-temperature conditions, leading to a loss of sperm vitality. However, the Y-27632 small molecule has not yet been used in research on low-temperature preservation of goat semen. This study aims to address the issue of low temperature-induced loss of sperm motility in goats by using Y-27632, and explore the regulation of Y-27632 on goat sperm metabolism. At a low temperature of 4 °C, different concentrations of Y-27632 were added to the sperm diluent. The regulation of Y-27632 on the quality of low temperature-preserved goat semen was evaluated by detecting goat sperm motility, antioxidant capacity, mitochondrial activity, cholesterol levels, and metabolomics analysis. The results indicated that 20 µM Y-27632 significantly increased plasma membrane integrity (p < 0.05), and acrosome integrity (p < 0.05) and sperm motility (p < 0.05), increased levels of superoxide dismutase (SOD) and catalase (CAT) (p < 0.01), increased total antioxidant capacity (T-AOC) (p < 0.05), decreased levels of malondialdehyde (MDA) and reactive oxygen species (ROS) (p < 0.01), and significantly increased mitochondrial membrane potential (MMP). The levels of ATP, Ca2+, and TC in sperm increased (p < 0.01). Twenty metabolites with significant differences were identified, with six metabolic pathways having a significant impact, among which the D-glutamic acid and D-glutamine metabolic pathways had the most significant impact. The artificial insemination effect of goat semen treated with 20 μM Y-27632 was not significantly different from that of fresh semen. This study indicates that Y-27632 improves the quality of low-temperature preservation of sperm by protecting the sperm plasma membrane, enhancing sperm antioxidant capacity, regulating D-glutamine and D-glutamate metabolism, and promoting the application of low-temperature preservation of semen in artificial insemination technology.

An Efficient Workflow for Quality Control Marker Screening and Metabolite Discovery in Dietary Herbs by LC-Orbitrap-MS/MS and Chemometric Methods: A Case Study of Chrysanthemum Flowers

LC-MS is widely utilized in identifying and tracing plant-derived food varieties but quality control markers screening and accurate identification remain challenging. The adulteration and confusion of Chrysanthemum flowers highlight the need for robust quality control markers. This study established an efficient workflow by integrating UHPLC-Orbitrap-MS/MS with Compound Discoverer and chemometrics. This workflow enabled the systematic screening of 21 markers from 10,540 molecular features, which effectively discriminated Chrysanthemum flowers of different species and cultivars. The workflow incorporated targeted and untargeted methods by employing diagnostic product ions, fragmentation patterns, mzCloud, mzVault, and in-house databases to identify 206 compounds in the flowers, including 17 screened markers. This approach improved identification accuracy by reducing false positives, eliminating in-source fragmentation interference, and incorporating partial verification utilizing our established compound bank. Practically, this workflow can be instrumental in quality control, geolocation determination, and varietal tracing of Chrysanthemum flowers, offering prospective use in other plant-derived foods.

[Narcotic Use under Probation and Parole Supervision - A longitudinal Study of Risk-group-specific Recidivism under Abstinence Conditions]

STUDY OBJECTIVE

The aim of this long-term study was to record substance-specific prevalences of illegal use of narcotics despite court-imposed abstinence requirements.

METHODS

Urine assays were obtained by a public health department on the basis of administrative assistance for the probation department of a district court. The individual and valid allocation of these urine samples was ensured using a proven marker system. After postal dispatch, laboratory chemical analyses for narcotics residues were carried out in an external laboratory via enzyme immunoassay and validation by mass spectrography in the case of positive narcotics results. On the basis of all available routine data, a pooled data set covering a total of fourteen consecutive calendar years (2006-2019) was generated digitally and evaluated anonymously.

RESULTS

From a total of 380 subjects (female: 13% versus male: 87%; average age: 30.4 years), 13,500 individual narcotic substance analyses from 2,941 urine samples were available. In 2.7% of all individual analyses, at least one of eight potential narcotic substances was detected, whereby the highest overall prevalences in the sense of a relapse were found for cannabis with 3.7% and for opiates with 2.4%. In contrast, there were almost no residues for barbiturates and LSD and no positive evidence for buprenorphine and PCP. As expected, most relapses in all narcotics groups were found in the age groups from 18 to 35 years. Strikingly, more women than men violated the court abstinence order with amphetamines, while relapses with the other seven narcotics groups occurred predominantly among men. In the course of the entire observation period, the most marked fluctuations in relapse rates were found for cannabis, opiates and cocaine.

CONCLUSION

The use of narcotic substances during probation and parole supervision does not appear to be a rare occurrence and has received little professional attention. Increased attention to this group-specific recidivism and more studies on this topic should help reduce this deficit.

Xylazine Poisoning in Clinical and Forensic Practice: Analysis Method, Characteristics, Mechanism and Future Challenges

Xylazine abuse is emerging globally, while the identification of xylazine lethal cases poses a great challenge in clinical and forensic practice. The non-specific symptoms delay the diagnosis and treatment of xylazine poisoning, the pathological changes and lethal concentration of xylazine in body fluid and organs of fatal xylazine poisoning cases are seldom reported and the other toxins detected in such cases complicate the role of xylazine in the cause of death. Therefore, we carefully reviewed related updated information on xylazine, summarized the knowledge from clinical and forensic perspectives and can thus provide a reference in such cases and throw light on further study in the field of xylazine poisoning.

Relapses in Illicit Drug Use Among Probationers: Results in a Risk Group of Public Health Services in Bavaria

Objective: We aimed to identify in this study time trends of relapses in the illicit consumption of narcotics in a special at-risk population of former drug users under a public health perspective. Methods: In a pooled dataset of 14 consecutive calendar years (2006-2019), the use of seven different narcotic substances was studied in 380 persons with a total of 2,928 urine samples which were analyzed using a valid marker system for narcotic residues. Results: During the entire observation period, the relapse rate for cannabinoids and opiates was the highest despite abstinence requirements. It was noticeable that the relapses across all narcotics groups occurred primarily during the first 3 years of the probation period (90%) with a decrease in illegal consumption during the following years of the observation period. Conclusion: Special attention should be paid to probationers at the beginning of the probation period to develop more effective prevention strategies for substance abstinence by all involved actors in public health services.

Development of a Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Method for Characterizing Linalool Oral Pharmacokinetics in Humans

Lavender (Lavandula angustifolia Miller or Lavandula officinalis Chaix) is an ethnopharmacological plant commonly known as English lavender. Linalool and linalyl acetate are putative phytoactives in lavender essential oil (LEO) derived from the flower heads. LEO has been used in aroma or massage therapy to reduce sleep disturbance and to mitigate anxiety. Recently, an oral LEO formulation was administered in human clinical trials designed to ascertain its anxiolytic effect. However, human pharmacokinetics and an LC-MS/MS method for the measurement of linalool are lacking. To address this deficiency, a rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the analysis of linalool in human serum. Prior to the analysis, a simple sample preparation protocol including protein precipitation and liquid-liquid extraction of serum samples was created. The prepared samples were analyzed using a C18 reversed-phase column and gradient elution (acetonitrile and water, both containing 0.1% formic acid). A Waters Xevo TQ-S tandem mass spectrometer (positive mode) was used to quantitatively determine linalool and IS according to transitions of m/z 137.1→95.1 (tR 0.79 min) and 205.2→149.1 (tR 1.56 min), respectively. The method was validated for precision, accuracy, selectivity, linearity, sensitivity, matrix effects, and stability, and it was successfully applied to characterize the oral pharmacokinetics of linalool in humans. The newly developed LC-MS/MS-based method and its application in clinical trial serum samples are essential for the characterization of potential pharmacokinetic and pharmacodynamic interactions.

OSCA-finder: Redefining the assay of kidney disease diagnostic through metabolomics and deep learning

Liquid chromatography-mass spectrometry (LC-MS) is a platform for urine and blood sample analysis. However, the high variability in the urine sample reduced the confidence of metabolite identification. Therefore, pre and post-calibration operations are inevitable to ensure an accurate urine biomarker analysis. In this study, the phenomenon of a higher creatinine concentration variable in ureteropelvic junction obstruction (UPJO) patient urine samples than in healthy people was revealed, indicating the urine biomarker discovery of UPJO patients is not adapted to the creatinine calibrate strategy. Therefore, we proposed a pipeline "OSCA-Finder" to reshape the urine biomarker analysis. First, to ensure a more stable peak shape and total ion chromatography, we applied the product of osmotic pressure and injection volume as a calibration principle and integrated it with an online mixer dilution. Therefore, we obtained the most peaks and identified more metabolites in a urine sample with peak area group CV<30%. A data-enhanced strategy was applied to reduce the overfit while training a neural network binary classifier with an accuracy of 99.9%. Finally, seven accurate urine biomarkers combined with a binary classifier were applied to distinguish UPJO patients from healthy people. The results show that the UPJO diagnostic strategy based on urine osmotic pressure calibration has more potential than ordinary strategies.