Liquid Chromatography-mass Spectrometry Method Research Articles

Pharmacokinetics and metabolite identification of 23-hydroxybetulinic acid in rats by using liquid chromatography-mass spectrometry method

23-hydroxybetulinic acid (23-HA), a main bioactive component isolated from Pulsatilla chinensis (Bunge) Regel, exhibits various pharmacological activities, such as antimelanoma, antileukemia, anti-colon cancer, and antihepatotoxicity. Although the main active ingredient anemoside B4 (AB4) from this plant has been well studied, research on its active metabolite 23-HA is limited. In the present study, a validated HPLC-QQQ-MS/MS method was established for the quantification of 23-HA in rat plasma. Pharmacokinetics analysis showed that the absorption and elimination of 23-HA in rats were rapid, with an oral bioavailability as 12.9 %. After oral administration with 50 mg/kg 23-HA for SD rats, the plasma, urine, feces, and bile samples were collected and analyzed by UPLC-Q Exactive Plus MS and HPLC-QQQ-MS/MS. Seventeen metabolites of 23-HA were identified, and its major metabolic pathways included oxidation, hydration, sulfation, and glucuronidation. This study highlights the first detailed investigation of 23-HA’s pharmacokinetics in rats along with its metabolism in vivo, and will provide robust evidence for further research and clinical application of 23-HA.

Amphetamine-type drug-related fatalities in the context of 8years of methamphetamine use measured by wastewater analysis in South Australia.

Methamphetamine is the illicit stimulant of choice in Australia. Countless initiatives have been employed to reduce methamphetamine use and drug-related harm. Wastewater analysis (WWA) has been used effectively as an objective measure of drug use at a population level and can be compared to indicators of harm, such as the number of drug-related fatalities. This paper attempts to describe methamphetamine use in the context of changes in levels measured in wastewater in South Australia whilst recognising considerable interventions over an 8-year period. Validated liquid chromatography-mass spectrometry methods were used to determine methamphetamine (and MDMA) levels in wastewater over an 8-year interval. The number of drug-induced deaths and driver fatalities involving methamphetamine (and MDMA) was presented and described in the context of changes in use measured by WWA. A rise in methamphetamine use according to WWA was evident up to 2017, followed by a gradual decrease to 2020 back to 2015 levels. Both driver fatalities and drug-induced deaths correlated well with use measured by WWA over the 8-year period. Multiple initiatives to curb supply, distribution and harm within the state and nationally have been implemented. The decrease in methamphetamine use after 2017 suggests that timely interventions have successfully reduced overall drug use and has led to fewer fatalities. This study shows that the response to increasing methamphetamine use in South Australia has resulted in a reversal of the upward trend in consumption and fewer drug-related fatalities.

BIOANALYTICAL METHOD DEVELOPMENT AND VALIDATION OF 2-(4-ETHOXYPHENYL SULPHONAMIDO) PENTANE-DIAMIDE, A NOVEL ANTITUMOR AND ANTIANGIOGENIC AGENT, IN RAT SERUM AND APPLICATION OF THE METHOD IN DETERMINATION OF PHARMACOKINETIC PARAMETERS

Objective: The present study focuses on the development and validation of a bioanalytical method for the quantification of 2-(4-ethoxyphenyl sulphamido) pentane-diamide, a candidate antitumor and antiangiogenic agent, in rat serum. The developed method was subsequently applied to determine the pharmacokinetic parameters of the compound. Methods: To quantify the compound and determine its pharmacokinetic properties in rats, a liquid chromatography-mass spectrometry (LC-MS) bioanalytical method has been developed and the pharmacokinetic parameters were computed by compartmental model analysis. Results: A linear relationship was detected within the concentration range of 10 to 5000 ng/ml prepared by adding standard solutions of the test compound to the pooled serum of 10 SD rats, which exhibits high levels of precision, accuracy, and reproducibility. An appreciable recovery in the range of 97.20±0.63 to 93.22±1.48 percent was determined, with no noticeable impact from the matrix. The pharmacokinetic parameters, namely oral absorption rate constant (Ka) (5.054±0.238 1/h), elimination rate constant (KE) (2.585±0.357 h), volume of distribution (V) (8.173±0.333 L/kg), and bioavailability of (73.2%), were determined by the utilization of PK-solver software. Conclusion: We developed a simple yet precise and validated LC-MS method to analyze the drug candidate in rat serum. Simple protein precipitation and extraction were cost-effective. This bioanalytical approach was successful due to its good linearity, high recoveries, no matrix influence, and matrix stability. PK solver derived I. V. and oral pharmacokinetics parameters from the best-fit one-compartment model. Because of its high oral absorption, biological half-life, and bioavailability, the compound is suitable for oral administration.

Absolute Quantification of Human Serum Albumin Isoforms by Internal Calibration Based on a Top-Down LC-MS Approach.

Well-characterized biomarkers using reliable quantitative methods are essential for the management of various pathologies such as diabetes, kidney, and liver diseases. Human serum albumin (HSA) isoforms are gaining interest as biomarkers of advanced liver pathologies. In view of the structural alterations observed for HSA, insights into its isoforms are required to establish them as reliable biomarkers. Therefore, a robust absolute quantification method seems necessary. In this study, we developed and validated a far more advanced top-down liquid chromatography-mass spectrometry (LC-MS) method for the absolute quantification of HSA isoforms, using myoglobin (Mb) as an internal standard for quantification and for mass recalibration. Two different quantification approaches were investigated based on peak integration from the deconvoluted spectrum and extracted ion chromatogram (XIC). The protein mixture human serum albumin/myoglobin eluted in well-shaped separated peaks. Mb allowed a systematic mass recalibration for every sample, resulting in extremely low mass deviations compared to conventional deconvolution-based methods. In total, eight HSA isoforms of interest were quantified. Specific-isoform calibration curves showing good linearity were obtained by using the deconvoluted peaks. Noticeably, the HSA ionization behavior appeared to be isoform-dependent, suggesting that the use of an enriched isoform solution as a calibration standard for absolute quantification studies of HSA isoforms is necessary. Good repeatability, reproducibility, and accuracy were observed, with better sensitivity for samples with low albumin concentrations compared to routine biochemical assays. With a relatively simple workflow, the application of this method for absolute quantification shows great potential, especially for HSA isoform studies in a clinical context, where a high-throughput method and sensitivity are needed.

Motilin fluctuations in healthy volunteers determined by liquid chromatography mass spectrometry.

Motilin is a hormone secreted by specialised enteroendocrine cells in the small intestine, and is known to modulate gastrointestinal motility in humans, regulating the migratory motor complex. It is understudied at least in part due to the lack of commercially available immunoassays. A multiplexed liquid chromatography mass spectrometry (LC-MS/MS) method was optimised to measure motilin, insulin, C-peptide, GIP (1-42) and GIP (3-42). Corresponding active ghrelin concentrations were determined by immunoassay. Ten healthy volunteers with no prior history of gastroenterological or endocrine condition attended after overnight fast and had blood samples taken every 15 minutes for 4 hours whilst continuing to fast, and then further sampling for 2 hours following a liquid mixed meal. Hunger scores were taken at each time point using a visual analogue scale. Normal bowel habit was confirmed by 1 week stool diary. Motilin levels fluctuated in the fasting state with an average period between peaks of 109.5 mins (SD:30.0), but with no evidence of a relationship with either ghrelin levels or hunger scores. The mixed meal interrupted cyclical motilin fluctuations, increased concentrations of motilin, insulin, C-peptide, GIP(1-42) and GIP(3-42), and suppressed ghrelin levels. This study highlights the utility of LC-MS/MS for parallel measurement of motilin alongside other peptide hormones, and supports previous reports of the cyclical nature of motilin levels in the fasting state and interruption with feeding. This analytical method has utility for further clinical studies into motilin and gut hormone physiology in human volunteers.

Analysis of synthetic route and case correlation of methamphetamine crystals seized by ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) and Pearson correlation coefficient method.

Analysis of impurities in illicit drugs provides key information on the manufacture and distribution of methamphetamine (MA). An analysis of 22 specific target compounds in unlawful MA products was conducted using ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). The peak area of the alkaloids was utilized as an important calculation data variable to determine the synthesis method. The results demonstrated that the application of target screening techniques for trace impurity components in samples can aid in determining the synthesis process routes for toxin production in 169 samples. These samples were initially categorized based on their synthesis modes, specifically synthesis routes N, E, and R. The correlation analysis of MA samples with known synthetic routes was carried out using principal coordinate analysis (PCoA) and the Pearson correlation coefficient method. Among the N and R synthesis routes, 15 and 7 groups with strong correlation were screened, respectively. Consistent with the observed scenario, the samples from the synthetic route E showed limited correlation with each other. The experiment provides a focused framework for the management of synthetic raw materials used for the production of drugs and the investigation of drug-related cases. This facilitates a holistic strategy to combat drug-related crimes, from manufacturing laboratory to end-user.

Organophosphate esters in human serum: a relatively simple and efficient liquid chromatography-mass spectrometry method.

Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers, which are of growing concern due to their endocrine-disrupting effects, developmental toxicity, and potential carcinogenicity. However, data on human exposure to OPEs is still scarce. In this study, a relatively simple and efficient method with less serum consumption for the detection of OPEs in human serum was developed and validated. Nine OPEs in 200 μL of human serum were extracted by an acetonitrile-formic acid system and analyzed using ultra-high-performance liquid chromatography-quadrupole tandem time-of-flight high-resolution mass spectrometry. Several experiments were conducted to optimize the chromatographic and mass spectrometric conditions as well as sample preparation to obtain a more sensitive and efficient analytical protocol. The proposed method was examined in terms of its linearity, accuracy, precision, detection limit, and matrix effect. The matrix-spiked recoveries of the target OPEs ranged from 83.3% to 111.1%, with relative standard deviations between 2.7% and 16.6%. The detection limits were within (0.002 to 0.029) ng mL-1, while the quantification limits were within (0.007 to 0.098) ng mL-1. The internal standard-corrected matrix effects varied from 82.7% to 113.9%. Finally, the method was applied to detect OPEs in actual human serum samples. All nine OPEs were detected in 269 serum samples to varying degrees, with the average concentrations ranging from (0.08 to 1.77) ng mL-1. After validation, the method was found to be simple in pretreatment, high in sensitivity, good in practicality, and suitable for exposure evaluation of OPEs in populations.

Systemic and Brain Pharmacokinetics of Milnacipran in Mice: Comparison of Intraperitoneal and Intravenous Administration.

Milnacipran is a dual serotonin and norepinephrine reuptake inhibitor, clinically used for the treatment of major depression or fibromyalgia. Currently, there are no studies reporting the pharmacokinetics (PK) of milnacipran after intraperitoneal (IP) injection, despite this being the primary administration route in numerous experimental studies using the drug. Therefore, the present study was designed to investigate the PK profile of IP-administered milnacipran in mice and compare it to the intravenous (IV) route. First a liquid chromatography-mass spectrometry (LC-MS/MS) method was developed and validated to accurately quantify milnacipran in biological samples. The method was used to quantify milnacipran in blood and brain samples collected at various time-points post-administration. Non-compartmental and PK analyses were employed to determine key PK parameters. The maximum concentration (Cmax) of the drug in plasma was at 5 min after IP administration, whereas in the brain, it was at 60 min for both routes of administration. Curiously, the majority of PK parameters were similar irrespective of the administration route, and the bioavailability was 92.5% after the IP injection. These findings provide insight into milnacipran's absorption, distribution, and elimination characteristics in mice after IP administration for the first time and should be valuable for future pharmacological studies.

Follicular Fluid Proteomic Analysis of Women Undergoing Assisted Reproduction Suggests That Apolipoprotein A1 Is a Potential Fertility Marker.

Infertility affects millions worldwide, posing a significant global health challenge. The proteomic analysis of follicular fluid provides a comprehensive view of the complex molecular landscape within ovarian follicles, offering valuable information on the factors influencing oocyte development and on the overall reproductive health. The follicular fluid is derived from the plasma and contains various proteins that can have different roles in oocyte health and infertility, and this fluid is a critical microenvironment for the developing oocytes as well. Using the high-performance liquid chromatography-mass spectrometry method, we investigated the protein composition of the follicular fluid, and after classification, we carried out relative quantification of the identified proteins in the pregnant (P) and non-pregnant (NP) groups. Based on the protein-protein interaction analysis, albumin and apolipoprotein A1 (ApoA1) were found to be hub proteins, and the quantitative comparison of the P and NP groups resulted in a significantly lower concentration of ApoA1 and high-density lipoprotein cholesterol in the P group. As both molecules are involved in the cholesterol transport, we also investigated their role in the development of oocytes and in the prediction of fertility.

Ranolazine Quantification in Human Plasma: A QbD-Guided LC-MS Method Development and Validation

The present research outlines a comprehensive and systematic approach for the development and validation of a bioanalytical Liquid chromatography–mass spectrometry (LC-MS) method to quantify ranolazine in human plasma. The study employs principles of quality by design (QbD) to enhance method robustness, precision, and accuracy. The primary goals of this research were to create a reliable LC-MS method for the accurate quantification of ranolazine in human plasma and to validate this approach in accordance with established standards set by regulatory bodies. A secondary objective was to explore the application of QbD principles to optimize method performance. The study resulted in the successful development of an LC-MS method that exhibits exceptional specificity, sensitivity, accuracy, and precision in the quantification of ranolazine in human plasma. Specificity tests revealed no interference from endogenous plasma components. The method demonstrated good sensitivity with limit of quantitation (LoQ) of 5 ng/mL and limit of detection (LoD) of 2 ng/mL. Accuracy, as assessed through recovery studies, showed mean recoveries of 98, 99, and 101% for three different spiked concentrations. Precision, expressed as RSD, was below 5% for both intra-day and inter-day analyses. Linearity studies resulted in a calibration curve with an R² value of 0.9998. By employing QbD principles, the method demonstrated improved robustness, thus minimizing the impact of variability during sample analysis. Robustness experiments revealed minimal effects on precision and accuracy when varying critical parameters. This research not only presents a reliable LC-MS method for ranolazine quantification but also underscores the importance of incorporating QbD principles in bioanalytical method development. The validated method holds significant implications for clinical research, pharmacokinetic studies, and therapeutic drug monitoring. By enhancing the accuracy and robustness of ranolazine quantification, this method contributes to the advancement of pharmaceutical and clinical research, ultimately benefiting patient care and treatment outcomes.

Clinical pharmacokinetic evaluation of Withania somnifera (L.) Dunal root extract in healthy human volunteers: A non-randomized, single dose study utilizing UHPLC-MS/MS analysis

Ethnopharmacological relevanceWithania somnifera (L.) Dunal; (Solanaceae), commonly known as Ashwagandha, is one of the most significant medicinal herbs in ‘Ayurveda’, a traditional Indian medicine used for centuries with evidence in scriptures. Ashwagandha was mentioned in old Ayurvedic medical literature such as Charaka Samhita and Sushruta Samhita for improving weight and strength, with multiple citations for internal and exterior usage in emaciation and nourishing the body. Ethnopharmacological evidence revealed that it was used to relieve inflammation, reduce abdominal swelling, as a mild purgative, and treat swollen glands. The root was regarded as a tonic, aphrodisiac, and emmenagogue in the Unani tradition of the Indian medicinal system. Further, Ashwagandha has been also described as an Ayurvedic medicinal plant in the Ayurvedic Pharmacopoeia of India extending informed therapeutic usage and formulations. Despite the widespread ethnopharmacological usage of Ashwagandha, clinical pharmacokinetic parameters are lacking in the literature; hence, the findings of this study will be relevant for calculating doses for future clinical evaluations of Ashwagandha root extract. AimThis study aimed to develop a validated and highly sensitive bioanalytical method for quantifying withanosides and withanolides of the Ashwagandha root extract in human plasma to explore its bioaccessibility. Further to apply a developed method to perform pharmacokinetics of standardized Withania somnifera (L.) Dunal root extract (WSE; AgeVel®/Witholytin®) capsules in healthy human volunteers. MethodsA sensitive, reliable, and specific ultra-high pressure liquid chromatography-mass spectrometry (UHPLC-MS/MS) method was developed and validated for the simultaneous quantification of five major withanosides and withanolides (withanoside IV, withanoside V, withanolide A, withaferin A, and 12-deoxy-withastramonolide) in human plasma. Further for the study, eighteen healthy male volunteers (18–45 years) were enrolled in a non-randomized, open-label, single period, single treatment, clinical pharmacokinetic study and given a single dose (500 mg) of WSE (AgeVel®/Witholytin®) capsules containing not less than 7.5 mg of total withanolides under fasting condition. Later, pharmacokinetic profiles were assessed using the plasma concentration of each bioactive constituent Vs. time data. ResultsFor all five constituents, the bioanalytical method demonstrated high selectivity, specificity, and linearity. There was no carryover, and no matrix effect was observed. Furthermore, the inter-day and intra-day precision and accuracy results fulfilled the acceptance criteria. Upon oral administration of WSE capsules, Cmax was found to be 0.639 ± 0.211, 2.926 ± 1.317, 2.833 ± 0.981, and 5.498 ± 1.986 ng/mL for withanoside IV, withanolide A, withaferin A, and 12-deoxy-withastramonolide with Tmax of 1.639 ± 0.993, 1.361 ± 0.850, 0.903 ± 0.273, and 1.375 ± 0.510 h respectively. Further, withanoside V was also detected in plasma; but its concentration was found below LLOQ. ConclusionThe novel and first-time developed bioanalytical method was successfully applied for the quantification of five bio-active constituents in human volunteers following administration of WSE capsules, indicating that withanosides and withanolides were rapidly absorbed from the stomach, have high oral bioavailability, and an optimum half-life to produce significant pharmacological activity. Further, AgeVel®/Witholytin® was found safe and well tolerated after oral administration, with no adverse reaction observed at a 500 mg dose.

A liquid chromatography-mass spectrometry method for the enantioselective multiresidue determination of nine chiral agrochemicals in urine using an enrichment procedure based on graphitized carbon black.

Many agrochemicals are chiral molecules, and most of them are marketed as racemates or diastereomeric mixtures. Stereoisomers that are not the active enantiomer have little or no pesticidal activity and can exert serious toxic effects towards non-target organisms. Thus, investigating the possible exposure to different isomers of chiral pesticides is an urgent need. The present work was aimed at developing a new enantioselective high-performance liquid chromatography-mass spectrometry method for the simultaneous determination of nine chiral pesticides in urine. Two solid-phase extraction (SPE) procedures, based on different carbon-based sorbents (graphitized carbon black (GCB) and buckypaper (BP)), were developed and compared. By using GCB, all analytes were recovered with yields ranging from 60 to 97%, while BP allowed recoveries greater than 54% for all pesticides except those with acid characteristics. Baseline separation was achieved for the enantiomers of all target agrochemicals on a Lux Cellulose-2 column within 24min under reversed-phase mode. The developed method was then validated according to the FDA guidelines for bioanalytical methods. Besides recovery, the other evaluated parameters were precision (7-15%), limits of detection (0.26-2.21µg/L), lower limits of quantitation (0.43-3.68µg/L), linear dynamic range, and sensitivity. Finally, the validated method was applied to verify the occurrence of the pesticide enantiomers in urine samples from occupationally exposed workers.

Bioanalytical Method Development and Validation of Doxorubicin and Lapatinib in Rat Plasma Using UHPLC-HESI-LTQ-MS

Abstract Cancer is considered a silent killer. The complexity of cancer makes it earn that title. So far there are only a few approaches to treat cancer. Among them, chemotherapy is considered the best approach. Many chemotherapeutical compounds are commercially available in the market. Among them, doxorubicin (DOX) and lapatinib (LAP) are considered blockbuster molecules. However, DOX suffers from poor bioavailability and exhibits cardiotoxicity. Interestingly, a fixed dose combination of DOX and LAP significantly decreases the cardiotoxic effect of DOX. To enhance the oral bioavailability of DOX and to avail the synergistic effect of LAP, many formulations have been made. To quantify both compounds in any formulation or biological matrix, an Liquid chromatography-Mass Spectrometry (LC-MS) method is required. In this present study, a simple and rapid Ultra High-Performance Liquid Chromatography - Heated Electron Spray Ionization - Mass Spectrometry (UHPLC-HESI-MS) bioanalytical method was developed. The developed method was validated as per the regulatory guidelines. The validated bioanalytical method had a lower limit of quantification of 0.75 ng. A simple protein precipitation technique was optimized to extract the compounds from the rat plasma. All the validation parameters were found to be within the limits as per the regulatory guidelines. A novel and rapid analytical method was successfully developed and validated. This developed method can be used to quantify the DOX and LAP in any formulation and biological matrix.

Stereoselective separation of omeprazole and 5-hydroxy-omeprazole using dried plasma spots and a heart-cutting 2D-LC approach for accurate CYP2C19 phenotyping

Omeprazole (OME) is a widely used gastric proton pump inhibitor, marketed as a racemic mixture comprising (S)- and (R)-enantiomers, with distinct pharmacokinetic profiles. OME is primarily metabolized by the cytochrome P450 enzymes 2C19 (CYP2C19) and 3A4 (CYP3A4). OME is a conventional probe for CYP2C19 phenotyping. Accurate measurement of these enantiomers and their metabolites is essential for pharmacokinetic studies. This article presents a sensitive and accurate two-dimensional liquid chromatography-mass spectrometry (LC-MS/MS) method for the simultaneous quantification of OME enantiomers and its hydroxylated metabolite (5-hydroxyomeprazole) in human plasma.The method involves an online extraction using an achiral Discovery HS C18 trapping column for purification (20 × 2.1 mm ID, 5μm particle size, Supelco) and subsequent forward flush elution onto a chlorinated phenylcarbamate cellulose-based chiral column (150x2mm ID, 3 μm particle size, Lux Cellulose-4, Phenomenex). The assay was fully validated and met international validation criteria for accuracy, precision, and stability and ensured high selectivity and sensitivity within a short runtime (<8 min). Application of this method to clinical samples demonstrated its utility in studying OME enantiomer pharmacokinetics, particularly its potential for phenotyping the activity of the CYP2C19 isoenzyme.This robust analytical approach offers a valuable tool for clinicians and researchers studying OME's pharmacokinetics, providing insights into its metabolism and potential implications for personalized medicine.

SFC-MS/MS for orthogonal separation of hydroxylated 17α-methyltestosterone isomers.

Because of their performance-enhancing effect, anabolic androgenic steroids (AAS) are often misused in sports. Nearly half of the adverse analytical findings (AAF) in 2022 doping controls are correlated to AAS misuse. Metabolites play a crucial role in the bioanalysis of endogenous and exogenous steroids. Therefore, one important field in antidoping research is the investigation on drug metabolizing and steroidogenic enzymes. The introduction of a hydroxy group is the most common reaction, which is catalyzed by cytochrome P450 (CYP) enzymes in phase-I metabolism. Analysis of AAS metabolites is commonly performed using gas chromatography mass spectrometry (GC-MS) systems. Laborious sample preparation and extended run times compared to liquid chromatography (tandem) mass spectrometry (LC-MS/MS)methods are usually correlated with this type of analysis. On the other hand, liquid chromatography (tandem) mass spectrometry (LC-MS[/MS]) methods have a lower separation efficiency than GC-MS methods. Both techniques lack selectivity for hydroxylated 17α-methyltestosterone metabolites. Therefore, as an orthogonal analytical approach, a supercritical fluid chromatography tandem mass spectrometrymethod was developed to separate four hydroxy metabolites of 17α-methyltestosterone (2α-/2β-/4-/6β-hydroxy-17α-methyltestosterone). This project aimed to get a more in-depth look at the metabolization and analysis of 17α-methyltestosterone and its hydroxylated metabolites. The developed method revealed lower limits of quantitation between 0.6 and 6ng/ml at an accuracy of 85-115% using a matrix matched calibration. An in vitro study with human liver microsomes shows 6β-hydroxy-17α-methyltestosterone as main metabolite (15.9%) as well as the metabolite 2β-hydroxy-17α-methyltestosterone (0.5%). The results show that the developed method is sensitive and robust. In addition, the method allows a previously missing discrimination of the hydroxylated metabolites in a short analysis time without prior, complex derivatizations.

Nutrimetric Validation of Solanidine as Dietary-Derived CYP2D6 Activity Marker InVivo.

CYP2D6 is involved in the metabolism of many drugs. Its activity is affected by pharmacogenetic variability leading to highly polymorphic phenotypes between individuals, affecting safety and efficacy of drugs. Recently, solanidine, a steroidal alkaloid from potatoes, and its metabolites, has been identified as a dietary-derived activity marker for CYP2D6. The intraday variability in plasma within individuals has not been studied yet in healthy subjects. As part of a CYP phenotyping cocktail study with 20 healthy participants, plasma concentrations of solanidine, 4-OH-solanidine and 3,4-secosolanidine-3,4-dioic acid (SSDA) were determined using a sensitive liquid chromatography-mass spectrometry method in urine and in plasma at timepoints 0, 2.5, 5, 8, and 24 hours after intake of test substances. The participants were phenotyped for CYP2D6 with oral metoprolol (12.5 mg) with 15 plasma sampling points over 24 hours (DRKS00028922). Metabolic ratios (MRs) of metabolite to parent plasma concentrations were formed from single timepoints and the area under the curve (AUC). All participants were genotyped for CYP2D6. The intra-individual variability of the CYP2D6 metabolite SSDA was highly stable with a median SD of 11.62% over 24 hours. MR SSDA/solanidine was more variable (median SD 31.90%) but correlated significantly at all measured timepoints with AUC MR α-OH-metoprolol/metoprolol. The AUC MR SSDA/solanidine showed a significant linear relationship with the genetically predicted CYP2D6 activity score. This study substantiates the MR SSDA/solanidine as CYP2D6 activity marker. The high correlation with metoprolol MR indicates a valid prediction of the CYP2D6 phenotype at any timepoint during the study day.

Liquid Chromatographic-Electron Spray Ionization-Mass Spectroscopy Technique for the Simultaneous Determination of Ethinyl Estradiol &amp; Etonogestrel and Characterization of New Forced Degradation Compounds

The aim of the current study was to develop, validate a precise, rapid, accurate liquid chromatography-mass spectrometry (LC-MS) method for the simultaneous estimation of ethinyl estradiol and etonogestrel. The retention times of ethinyl estradiol and etonogestrel were found at 3.112 min and 4.399 min, respectively, whereas the linear range were found in the concentration ranges from 0.04-0.23 µg/mL &amp; 3-18 µg/mL with slope coefficient (R2) of 0.9992 and 0.9991 correspondingly. Similarly, the accuracy values for ethinyl estradiol and etonogestrel were found to be 100.5% and 100.1% correspondingly. As per ICH Q2(R1) guidelines, the method was validated with liquid chromatography-mass spectrometry to confirm the newly obtained degradation compounds chemical structures of ethinyl estradiol and etonogestrel.

Development of a second-tier method for C4, C5 and C2 acylcarnitine analysis in plasma

IntroductionAcylcarnitines are typically analyzed using either a flow injection analysis (FIA) method or liquid chromatography-mass spectrometry (LC-MS/MS) methods. The FIA method is a fast, efficient method, however it does not have the capability to separate compounds with the same molecular weight. These isobaric interferences can be removed by chromatographic separation with LC-MS/MS. In this study, we aimed to develop and optimize a qualitative LC-MS/MS method to separate the isobaric interferences for two-, four- and five-carbon acylcarnitines. MethodsThe samples were first prepared by acylcarnitine derivatization with butanolic HCl. The developed LC-MS/MS method is a combination of isocratic and gradient elution used to separate acylcarnitines. Multiple reaction monitoring was used for determination of precursor and product ions for each acylcarnitine species as well as known interferences used in our study. We used this method to analyze quality assurance and patient samples with elevated two-, four- and five-carbon acylcarnitines. ResultsButyryl- and isobutyrylcarnitines as well as valeryl- and isovalerylcarnitines were successfully separated using the developed method. This method was able also to separate and distinguish acetylcarnitine from glutamate interference that has been causing overestimation of acetylcarnitine. In patients, the dominant five-carbon acylcarnitine was found to be isovalerylcarnitine. We confirmed that the majority of analyzed patient samples had additional carnitine adducts present but not valerylcarnitine. Butyryl- and isobutyrylcarnitines, in variable ratios, were present in every patient sample. ConclusionWe developed a qualitative LC-MS/MS method for butyl-ester derivatized acylcarnitines, which can be used as a second-tier method for diagnosis and monitoring of various inborn errors of metabolism in our hospital network.

Effects of Xiaoyao San on exercise capacity and liver mitochondrial metabolomics in rat depression model

ObjectiveThis study aimed to investigate the therapeutic effects of Xiaoyao San (XYS), a herbal medicine formula, on exercise capacity and liver mitochondrial metabolomics in a rat model of depression induced by chronic unpredictable mild stress (CUMS). MethodsA total of 24 male SD rats were randomly divided into four groups: control group (C), CUMS control group (M), Venlafaxine positive treatment group (V), and XYS treatment group (X). Depressive behaviour and exercise capacity of rats were assessed by body weight, sugar-water preference test, open field test, pole test, and rotarod test. The liver mitochondria metabolomics were analyzed by using liquid chromatography-mass spectrometry (LC-MS) method. TCMSP database and GeneCards database were used to screen XYS for potential targets for depression, and GO and KEGG enrichment analyses were performed. ResultsCompared with C group, rats in M group showed significantly lower body weight, sugar water preference rate, number of crossing and rearing in the open field test, climbing down time in the pole test, and retention time on the rotarod test (P < 0.01). The above behaviors and exercise capacity indices were significantly modulated in rats in V and X groups compared with M group (P < 0.05, 0.01). Compared with C group, a total of 18 different metabolites were changed in the liver mitochondria of rats in M group. Nine different metabolites and six metabolic pathways were regulated in the liver mitochondria of rats in X group compared with M group. The results of network pharmacology showed that 88 intersecting targets for depression and XYS were obtained, among which 15 key targets such as IL-1β, IL-6, and TNF were predicted to be the main differential targets for the treatment of depression. Additionally, a total of 1 553 GO signaling pathways and 181 KEGG signaling pathways were identified, and the main biological pathways were AGE-RAGE signaling pathway, HIF-1 signaling pathway, and calcium signaling pathway. ConclusionXYS treatment could improve depressive symptoms, enhance exercise capacity, positively regulate the changes of mitochondrial metabolites and improve energy metabolism in the liver of depressed rats. These findings suggest that XYS exerts antidepressant effects through multi-target and multi-pathway.

Development and Validation of a Liquid Chromatography Mass Spectrometry Method to Measure Highly Concentrated Tacrolimus and Cyclosporine Specimens Prepared from Commercial Pharmaceutical Products to Assess Administration Through Feeding Tubes

Abstract Background Tacrolimus and cyclosporine are common immunosuppressive drugs used in the prevention and treatment of solid-organ transplant rejection (e.g., kidney, liver, heart). Other indications include several autoimmune diseases such as Crohn’s disease, autoimmune hepatitis, and rheumatoid arthritis. To prevent toxicity while achieving therapeutic efficacy, tacrolimus and cyclosporine in whole blood specimens are commonly measured in medical centers so that their dosages can be precisely adjusted. Different from adult patients, pediatric patients often require smaller doses and the use of feeding tubes for drug administration. In order to assess nonspecific adsorption by feeding tubes, we modified our in-house clinical method to measure highly concentrated tacrolimus and cyclosporine specimens prepared from clinical pharmaceutical products. Method: Highly concentrated tacrolimus and cyclosporine specimens were serially diluted with dimethyl sulfoxide (2,000 times for tacrolimus and 20,000 times for cyclosporine) before measurements by our clinical method using liquid chromatography mass spectrometry. The method for highly concentrated tacrolimus and cyclosporine was validated, with analytical measurement range determined with in-house prepared concentrated specimens at varying concentrations, precision (repeatability and reproducibility) assessed by multiple measurements of concentrated specimens at three different concentrations, accuracy assessed by recovery studies, and matrix effect assessed by post-column infusion and by matrix dilution with dimethyl sulfoxide. Results The method was linear from 10 ug/mL to 80 ug/mL for tacrolimus, and 1 mg/mL to 8 mg/mL for cyclosporine with r2 &amp;gt; 0.99. Repeatability and reproducibility were &amp;lt;10% CV. Minimal matrix effect was observed. Recovery studies using commercial calibrators to measure specimens prepared from reference materials and dimethyl sulfoxide identified no significant bias for tacrolimus but an average positive bias of 20% for cyclosporine, and a correction factor was used to finalize cyclosporine results for specimens prepared from clinical pharmaceutical products. The positive bias was eliminated when calibrators were prepared in dimethyl sulfoxide. Conclusion s: We have developed and validated a LC-MS/MS method for the measurement of highly concentrated tacrolimus and cyclosporine in specimens prepared from clinical pharmaceutical products. We hypothesize that one or more components in the commercial calibrators have contributed to the positive bias of cyclosporine in those specimens. Our method can be used to support studies that assess nonspecific adsorption by feeding tubes.