Rapid Liquid Chromatography-tandem Mass Spectrometry Research Articles

Quantification of fenoprofen in human plasma using UHPLC-tandem mass spectrometry for pharmacokinetic study in healthy subjects.

A rapid, simple and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed to quantify fenoprofen, a nonsteroidal anti-inflammatory drug in human plasma for a pharmacokinetic study in healthy subjects. Owing to high levels of protein binding, protein precipitation followed by solid-phase extraction was employed for the extraction of fenoprofen and fenoprofen-d3 (used as internal standard) from 200 μL human plasma. Separation was performed on a BEH C18 (50 × 2.1 mm, 1.7 μm) column using methanol-0.2% acetic acid in water (75:25, v/v) under isocratic elution. Electrospray ionization was operated in the negative mode for sample ionization. Ion transitions used for quantification in the selected reaction monitoring mode were m/z241/197 and m/z244/200 for fenoprofen and fenoprofen-d3, respectively. Under the optimized conditions, fenoprofen showed excellent linearity in the concentration range 0.02-20 μg/mL (r2 ≥ 0.9996), adequate sensitivity, favorable accuracy (96.4-103.7%) and precision (percentage coefficient of variation ≤4.3) with negligible matrix effect. The validated method was successfully applied to a pharmacokinetic study of fenoprofen in healthy subjects. The significant features of the method include higher sensitivity, small plasma volume for processing and a short analysis time.

Plasma and cerebrospinal fluid pharmacokinetics of hydroxysafflor yellow A in patients with traumatic brain injury after intravenous administration of Xuebijing using LC-MS/MS method

Hydroxysafflor yellow A (HSYA) is the most pharmaceutically relevant compound in Xuebijing (XBJ) for traumatic brain injury (TBI) treatment. We aimed to investigate biofluids pharmacokinetics of HSYA from XBJ to ensure the drug safety and to guide the clinical use.A sensitive, rapid and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was applied to investigate pharmacokinetics of HSYA in TBI patients after intravenous administration of XBJ. Non-compartmental methods using DAS 3.0 software were applied to analyse the pharmacokinetic parameters.A similar half-life (Plasmat1/2: 14.55 ± 3.51 h vs. CSFt1/2: 15.73 ± 3.63) was observed. HSYA reached the peak level rapidly, but exhibited a strongly slow absorption phase from blood to cerebrospinal fluid (CSF, PlasmaTmax: 0.69 ± 0.26 h vs. CSFTmax: 4.0 ± 2.62 h). HSYA exhibited much higher Cmax (PlasmaCmax: 9342.76 ± 2489.23 μg/L vs. CSFCmax: 98.08 ± 14.51 μg/L) and AUC0-t (PlasmaAUC0-t: 57490.5 ± 5560.3 μg h/L vs. CSFAUC0-t: 1851.6 ± 269.1 μg h/L), yet a shorter CL (PlasmaCL: 0.02 ± 0.002 L/h/kg vs. CSFCL: 0.55 ± 0.01 L/h/kg) in plasma than in CSF. The AUCCSF/AUCplasma of HSYA was almost 3.37%.In summary, the results demonstrate that part of HSYA come across blood-brain barrier after XBJ administration. This study provides evidence for better understanding the pharmacokinetics and potential for clinical guidance of XBJ for TBI treatment.

Predator-prey interactions between the ciliate Blepharisma americanum and toxic (Microcystis spp.) and non-toxic (Chlorella vulgaris, Microcystis sp.) photosynthetic microbes

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 83:211-224 (2019) - DOI: https://doi.org/10.3354/ame01913 Predator-prey interactions between the ciliate Blepharisma americanum and toxic (Microcystis spp.) and non-toxic (Chlorella vulgaris, Microcystis sp.) photosynthetic microbes Ian J. Chapman1,2, Daniel J. Franklin1, Andrew D. Turner3, Eddie J. A. McCarthy1, Genoveva F. Esteban1,* 1Bournemouth University, Department of Life and Environmental Sciences, Faculty of Science and Technology, Dorset, BH12 5BB, UK 2NSW Shellfish Program, NSW Food Authority, Taree, NSW 2430, Australia 3Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Weymouth, Dorset, DT4 8UB, UK *Corresponding author: gesteban@bournemouth.ac.uk ABSTRACT: Despite free-living protozoa being a major factor in modifying aquatic autotrophic biomass, ciliate-cyanobacteria interactions and their functional ecological roles have been poorly described, especially with toxic cyanobacteria. Trophic relationships have been neglected and grazing experiments give contradictory evidence when toxic taxa such as Microcystis are involved. Here, 2 toxic Microcystis strains (containing microcystins), 1 non-toxic Microcystis strain and a non-toxic green alga, Chlorella vulgaris, were used to investigate predator-prey interactions with a phagotrophic ciliate, Blepharisma americanum. Flow cytometric analysis for microalgal measurements and a rapid ultra high performance liquid chromatography-tandem mass spectrometry protocol to quantify microcystins showed that non-toxic photosynthetic microbes were significantly grazed by B. americanum, which sustained ciliate populations. In contrast, despite constant ingestion of toxic Microcystis, rapid egestion of cells occurred. The lack of digestion resulted in no significant control of toxic cyanobacteria densities, a complete reduction in ciliate numbers, and no observable encystment or cannibalistic behaviour (gigantism). Individual B. americanum morphological responses (biovolume and cell width) showed a significant decrease over time when sustained on non-toxic Microcystis compared to grazed C. vulgaris populations, supporting previous studies that cyanobacteria may be a relatively poor source of nutrition. Results here provide insight into the ecological interactions of ciliates and cyanobacteria, and for the first time B. americanum is shown to have the capacity to suppress potentially bloom-forming cyanobacteria. However, grazing can be significantly altered by the presence of microcystins, which could have an impact on bloom dynamics and overall community structure. KEY WORDS: Ciliate-cyanobacteria interactions · Toxic cyanobacteria · Ciliate · Grazing · Microcystis · Microcystins Full text in pdf format PreviousNextCite this article as: Chapman IJ, Franklin DJ, Turner AD, McCarthy EJA, Esteban GF (2019) Predator-prey interactions between the ciliate Blepharisma americanum and toxic (Microcystis spp.) and non-toxic (Chlorella vulgaris, Microcystis sp.) photosynthetic microbes. Aquat Microb Ecol 83:211-224. https://doi.org/10.3354/ame01913 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 83, No. 3. Online publication date: September 19, 2019 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2019 Inter-Research.

Pharmacokinetics and absolute oral bioavailability of stemazole by UPLC-MS/MS and its bio-distribution through tritium labeling.

The small molecule, stemazole, has significant therapeutic effects on neurodegenerative diseases, such as Alzheimer's disease (AD), due to its neuroprotective effects and remarkable survival-promoting activity in stem cells. However, pharmacokinetic properties of stemazole were unclear. In this study, a rapid and effective ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to detect stemazole. The detector was operated in the positive-ion mode with an electrospray ionization (ESI) interface in multiple reaction monitoring (MRM) mode. Chromatographic separation was performed on an Acquity UPLC® BEH C18 column with gradient elution. Stemazole was extracted from plasma following a one-step protein precipitation method. The method was fully validated for its selectivity, specificity, and sensitivity. The calibration curve range of 5-1125ng/mL showed good linearity for stemazole. Intra-day and inter-day precision rates were less than 10%, and accuracy ranged from 95.87% to 105.23%. The pharmacokinetic profiles were illustrated through the newly developed method for the first time. The absolute oral bioavailability of stemazole is 32.10%. Therefore, it is feasible as an oral medication, which greatly facilitates its broad application. The biological distribution of tritium-labeled stemazole in mice was studied, and the results showed that stemazole was absorbed rapidly and distributed widely, mainly in the liver and kidneys. A specific amount was also detected in the brain, which provides a prerequisite for the use of stemazole to treat neurodegenerative diseases. This work represents first description of the pharmacokinetics, bioavailability, and tissue distribution of stemazole and will lay the foundation for further investigation and drug development.

Development of an LC-MS/MS method for quantitative analysis of Chlorogenic acid in human plasma and its application to a pharmacokinetic study in Chinese patients with advanced solid tumor

A simple and specific, rapid resolution liquid chromatography-tandem mass spectrometry (LC–MS/MS) method was developed and validated for determination of chlorogenic acid in human plasma using neochlorogenic acid as the internal standard. Plasma samples were precipitated with methanol and separated on a Zorbax C18 column (50 × 2.1 mm, i.d. 1.8 μm) at a flow rate of 0.4 mL/min using a gradient mobile phase of methanol-water containing 0.1% formic acid (v/v). The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring in negative ESI mode. The method was fully validated over the concentration range of 10–2000 ng/mL. The indicators of inter- and intra-day precision (RSD%) were all within 10.7%, and the accuracy (RE%) was ranged from -3.0% to 10.6%. Moreover, we evaluated this bioanalytical method by re-analysis of incurred samples as an additional measure of assay reproducibility. This method was successfully applied to pharmacokinetic study of CGA in Chinese subjects with advanced solid tumor after intramuscular injection administration of Chlorogenic acid for injection (CAFI).

Ultra-performance liquid chromatography-tandem mass spectrometry quantitative profiling of tryptophan metabolites in human plasma and its application to clinical study

A sensitive, rapid and reliable ultra-performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS) method was developed and validated to assay tryptophan (TRP) and its nine metabolites, including kynurenine (KYN), kynurenic acid (KYNA), 3-hydroxykynurenine (3-HK), 3-hydroxyanthranilic acid (3-HAA), xanthurenic acid (XA), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), 3-indolepropionic acid (IPA) and 3-indoleacetic acid (IAA) in human plasma. Tryptophan-d5 (TRP-d5) and carbamazepine (CAR) were applied to the method quantification, where TRP-d5 was the corresponding internal standard (IS) for TRP and KYN, and CAR was the corresponding IS for the other analytes. Plasma samples were processed by deproteinisation with acetonitrile, followed by separation on an Acquity UPLC HSS T3 column by using gradient elution with 0.1% (v/v) formic acid in water and acetonitrile and detection by electrospray ionisation tandem mass spectrometry in positive ion multiple reaction monitoring (MRM) within a total run time of 5 min. The calibration ranges were 3–600 ng/mL for 3-HK, 1.5–300 ng/mL for 5-HT, 25–5000 ng/mL for KYN, 1–200 ng/mL for XA, 100–20,000 ng/mL for TRP, 5–1000 ng/mL for KYNA, 2–400 ng/mL for 3-HAA, 2.5–500 ng/mL for 5-HIAA and 10–2000 ng/mL for IAA and IPA. All intra- and inter-day analytical variations were acceptable. Matrix effect and recovery evaluation proved that matrix effect can be negligible, and sample preparation approach was effective. The newly developed method can simultaneously determine a panel of TRP metabolites and was successfully applied in the clinical study characterising TRP metabolism in healthy volunteers.

Analysis of the Carry-Over of Ochratoxin A from Feed to Milk, Blood, Urine, and Different Tissues of Dairy Cows Based on the Establishment of a Reliable LC-MS/MS Method.

A rapid and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of ochratoxin A (OTA) and its metabolite ochratoxin α (OTα), for the first time, in dairy cow plasma, milk, urine, heart, liver, spleen, lung, and kidney. The established method was extensively validated by determining the linearity (R2 ≥ 0.990), sensitivity (lower limit of quantification, 0.1–0.2 ng mL−1), recovery (75.3–114.1%), precision (RSD ≤ 13.6%), and stability (≥83.0%). Based on the methodological advances, the carry-over of OTA was subsequently studied after oral administration of 30 μg/kg body weight OTA to dairy cows. As revealed, OTA and OTα were detected in urine, with maximal concentrations of 1.8 ng mL−1 and 324.6 ng mL−1, respectively, but not in milk, plasma, or different tissues, verifying the protection effects of rumen flora against OTA exposure for dairy cows. Moreover, 100 fresh milk samples randomly collected from different supermarkets in Shanghai were also analyzed, and no positive samples were found, further proving the correctness of the in vivo biotransformation results. Thus, from the currently available data, regarding OTA contamination issues on dairy cows, no significant health risks were related to OTA exposure due to the consumption of these products.

Simultaneous Quantification of Seven Constituents from Zaoren Anshen Prescription and Four Endogenic Components in Rat Plasma by UHPLC-TSQ-MS/MS and the Application of the Correlation Study.

A highly rapid and sensitive ultra-performance liquid chromatography-tandem triple quadrupole mass spectrometry (UHPLC-TSQ-MS/MS) method was developed for the simultaneous determination of 7 constituents from Zaoren Anshen prescription (ZAP) and 4 endogenic components in rat plasma. The proteins in the plasma samples were removed using acetonitrile. The separation of the 11 components was performed on an Alltima C18 column (150 × 4.6 mm, 5 µm) with acetonitrile and 0.01% formic acid water as the mobile phase. Quantification of the 11 components was performed by multiple reaction monitoring (MRM), and the electrospray ion source polarity was switched between positive and negative modes. The method exhibited good linearity for the 11 components (R2 > 0.9942). The lower quantitative limit for the 11 components was in the range from 0.90-9.95 ng/mL. The precision was evaluated by intraday and interday assays, with all relative standard deviation (RSD)% values within 14.92%. The relative error of the accuracy ranged from -9.90 to 14.93%. The recovery ranged from 73.94 to 101.06%, and the matrix effects of the 7 components ranged from 80.06 to 105.70%. The developed method was successfully applied for correlation analysis for the simultaneous quantification of the 7 constituents from ZAP and 4 endogenic components in rat plasma after ZAP treatment.

Method Validation for Simultaneous Quantification of Olmesartan and Hydrochlorothiazide in Human Plasma Using LC-MS/MS and Its Application Through Bioequivalence Study in Healthy Volunteers.

A new, simple, sensitive, selective, rapid, and high-throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for simultaneous quantification of Olmesartan and hydrochlorothiazide in human plasma. Simple liquid–liquid extraction procedure was applied for plasma sample pretreatment using a mixture of diethyl ether and dichloromethane, as an extraction solution. Analytes were separated on UNISOL C18 150*4.6 mm, 5 µm column using methanol, and 2 mM ammonium acetate pH 5.5 (80:20, v/v) as a mobile phase and detected by electrospray ionization in the multiple reaction monitoring (MRM) mode. The mass transition ion pairs were followed in negative ion mode as m/z 445.20 → 148.90 for Olmesartan; m/z 451.40 → 154.30 for Olmesartan D6 and m/z 295.80 → 205.10 for hydrochlorothiazide; m/z 298.90 → 206.30 for hydrochlorothiazide 13C D2. The method showed excellent linearity (r 2 > 0.99) over the concentration range of 5.002–2,599.934 ng/ml for Olmesartan and from 3.005 to 499.994 ng/ml for hydrochlorothiazide. Precision (% CV) and accuracy (% bias) for Olmesartan were found in the range of 3.07–9.02% and −5.00–0.00%, respectively. Precision (% CV) and accuracy (% bias) for hydrochlorothiazide were found in the range of 3.32–8.21% and 1.99–3.80%, respectively. This as developed novel and high-throughput liquid–liquid extraction bioanalytical method has substantial innovative value with the benefits of cost effectiveness, good extraction efficiency, shorter analysis run time, low organic solvent consumption, and simpler procedure over the previously reported solid-phase extraction method. The application of this method in pharmacokinetic studies was further demonstrated successfully through a bioequivalence study conducted on healthy human subjects, following oral administration of combined formulation of Olmesartan medoxomil and hydrochlorothiazide in fixed-dose tablet.

Simultaneous determination of N-ethylpentylone, dopamine, 5-hydroxytryptamine and their metabolites in rat brain microdialysis by liquid chromatography tandem mass spectrometry.

N-Ethylpentylone (NEP) is a popular synthetic cathinone abused worldwide. To obtain more information about its pharmacokinetics and pharmacodynamics, a rapid, simple and sensitive liquid chromatography-tandem mass spectrometry method was developed for the determination of NEP, two important neurotransmitters, dopamine and serotonin, and their metabolites, including 3,4-dihydroxyphenylacetic acid, 3-methoxytyramine and 5-hydroxyindole-3-acetic acid, in rat brain microdialysate. The analytes were separated on a Phnomenex Polar C18 column, with a mobile phase of 0.1% formic acid in water (A) and 0.1% formic acid in acetonitrile (B) under gradient elution to shorten the total chromatographic run time. A triple quadruple mass spectrometer coupled with an electrospray ionization source in both positive and negative ion mode was used to detect the analytes. This method showed excellent accuracy (87.4-113.5%) and precision (relative standard deviation <15%) at three quality control levels. The limits of detection were 0.2 ng/mL for NEP and 0.2-50 nm for the others and good linearity was obtained. This study pioneered a method to integrate exogenous drugs and endogenous neurotransmitters as the drugs act on the same determination system, which means that this innovation can provide support for further study of the addictive effects of NEP or other synthetic cathinones on extracellular levels of dopamine and 5-hydroxytryptamine.

Simultaneous Determination of Seven Active Components in Rat Plasma by UHPLC-MS/MS and Application to a Quantitative Study after Oral Administration of Huang-Lian Jie-Du Decoction in High Fat-Induced Atherosclerosis Rats.

Huang-Lian Jie-Du decoction (HLJDD) has been used to treat cardiovascular and cerebrovascular disease for many years in China. Currently, the determination of effect components in HLJDD is focusing either on the formula or on the extract, while quantification of that in biological samples is scarce, especially simultaneous determination of multicomponent. In this paper, a rapid, specific, and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry method was developed and fully validated for the simultaneous determination of seven main active constituents, i.e., baicalin, baicalein, wogonoside, wogonin, berberine, palmatine, jatrorrhizine in rat plasma. The method was also successfully applied to a quantitative study after oral administration of HLJDD at different doses of 1.5, 3, and 6 g/kg body weight to high fat-induced atherosclerosis rats. The analytes were detected by ESI source and multiple reactions monitoring (MRM) using positive scanning mode. The blood was collected from the abdominal aorta of rats at predetermined time and preprepared with icariin and tetrahydropalmatine as internal standards (IS). Sample preparation was achieved by protein precipitation (PPT). The validation parameters (linearity, sensitivity, intra-/interday precision and accuracy, extraction recovery, and matrix effect) were within acceptable ranges, and biological extracts were stable during the entire storing and preparing process. And the result of determination of HLJDD-containing plasma, baicalin, baicalein, wogonoside, and wogonin could be highly detected in a dose-dependent manner while berberine, jatrorrhizine, and palmatine were determined in a very low level and in a dose-independent mode. Thus, the established method was sensitive enough and successfully applied to the determination of seven effective components in plasma taken from 24 high fat-induced atherosclerosis rats after oral administration of three dosages of HLJDD.

Liquid chromatography-tandem mass spectrometry to assess the pharmacokinetics and tissue distribution of withaferin A in rats

Withaferin A (WA) is a bioactive ingredient in the medicinal Indian herb Withania somnifera (WS). In this study, we developed a rapid and accurate Liquid Chromatography-tandem Mass Spectrometry (LC-MS/MS) method to determine the concentration of WA in rat plasma and tissue following intravenous (i.v., 4.5 mg/kg) and oral (i.g, 0.5, 1.5 and 4.5 mg/kg) administration. WA was isolated on a Hypurity C18 (50 × 4.6 mm, 5 μm) column by isocratic elution at a flow rate of 0.5 mL/min using acetonitrile and water as the mobile phase (35:65, v/v). The retention time was 4 min. Ethyl acetate containing 5% ascorbic acid was used as the extraction solvent through simple liquid-liquid extraction (LLE). Withanolide A (WLD) was used as the internal standard (IS). Quantification was performed through multiple reaction monitoring (MRM) modes of m/z 471.1 → 281 for WA and m/z 488.1 → 263 for IS in the positive-ion mode. This revealed no significant effects of the WA concentration or administration route on the T1/2. The distribution of WA in the various tissues was in the order: stomach > heart > lung > kidney > small intestinal > spleen > following i.g administration (4.5 mg/kg). These data provide valuable insight into the clinical parameters of WA.

Simultaneous determination of tandospirone and its active metabolite, 1-[2-pyrimidyl]-piperazine in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

A rapid, sensitive and selective liquid chromatography-tandem mass spectrometry method for the detection of tandospirone (TDS) and its active metabolite 1-[2-pyrimidyl]-piperazine (1-PP) in Sprague-Dawley rat plasma is described. It was employed in a pharmacokinetic study. These analytes and the internal standards were extracted from plasma using protein precipitation with acetonitrile, then separated on a CAPCELL PAK ADME C18 column using a mobile phase of acetonitrile and 5 mm ammonium formate acidified with formic acid (0.1%, v/v) at a total flow rate of 0.4 mL/min. The detection was performed with a tandem mass spectrometer equipped with an electrospray ionization source. The method was validated to quantify the concentration ranges of 1.000-500.0 ng/mL for TDS and 10.00-500.0 ng/mL for 1-PP. Total time for each chromatograph was 3.0 min. The intra-day precision was between 1.42 and 6.69% and the accuracy ranged from 95.74 to 110.18% for all analytes. Inter-day precision and accuracy ranged from 2.47 to 6.02% and from 98.37 to 105.62%, respectively. The lower limits of quantification were 1.000 ng/mL for TDS and 10.00 ng/mL for 1-PP. This method provided a fast, sensitive and selective analytical tool for quantification of tandospirone and its metabolite 1-PP in plasma necessary for the pharmacokinetic investigation.

Rapid liquid chromatography-tandem mass spectrometry to determine very-long-chain fatty acids in human and to establish reference intervals for the Chinese population

Very-long-chain fatty acids (VLCFAs), including hexacosanoic, tetracosanoic, and docosanoic acids, are peroxisomal disease markers, whose abnormal accumulation warrants prompt detection for timely, effective treatment. This study aimed to establish and validate a robust liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method to simultaneously quantify VLCFAs and provide reference intervals among Chinese individuals, quantify VLCFAs in pregnancy, and explore potential associations between plasma and amniotic fluid. Analytes were extracted via water-bath incubation with HCl and liquid-liquid extraction. Method linearity, limit of detection/quantitation, precision, carryover, and recovery were evaluated according to Clinical and Laboratory Standard Institute (CLSI) guidelines. VLCFAs showed good reproducibility based on low within-run coefficient variations (CVs) and total CVs, and correlation coefficients of linearity were > 0.99. The reference interval of C22:0, C24:0, and C26:0 were 32.0–73.4 μmol/L, 30.3–72.0 μmol/L, and 0.20–0.71 μmol/L, respectively; C24:0/C22:0 and C26:0/C22:0 ratios were 0.75–1.28 and 0.005–0.0139, respectively. Plasma and amniotic fluid of the same pregnant women displayed no significant correlation in the second trimester. This study presents the simple, efficient, accurate, and robust LC-MS/MS method to simultaneously detect C22:0, C24:0, and C26:0 without derivatization; it can be used to establish reference intervals among Chinese individuals and has diagnostic and other clinical applications.

Determination of fascaplysin in rat plasma with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS): application to a pharmacokinetic study

A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS) method was developed to determine fascaplysin in rat plasma using methylfascaplysin as an internal standard. Both fascaplysin and methylfascaplysin were synthesized in our laboratory. Protein precipitation was applied for the preparation of the plasma sample. Chromatographic separation was performed on a reversed-phase UPLC C18 column (1.8 μm, 100 mm × 2.1 mm) with a flow rate at 0.4 mL min−1. A triple-quadrupole mass spectrometer was employed for multiple reaction monitoring (MRM) in positive ionization mode. The MRM ion transitions m/z 271.0 → 242.1 and m/z 285.1 → 270.1 were selected to determine fascaplysin and methylfascaplysin respectively. The calibration curves for fascaplysin quantification showed excellent linearity in the range of 1–500 ng mL−1 with a limit of lower quantification (LLOQ) of 1 ng mL−1. The within-run and between-run accuracy ranged from 95.1% to 110.0% with precision lower than 7.4% in low, medium and high concentration levels for quality control (QC). The specificity, matrix effect, recovery, and stability were validated in accordance with the FDA bioanalytical method validation guidance. In the end, the proposed UPLC–MS/MS method was successfully applied in a pharmacokinetic study of fascaplysin after intravenous and intragastric administration to rats, which indicates a potential way for the preclinical study of fascaplysin in the future.

UHPLC-MS/MS quantitation of porphyroxine in opium and application of porphyroxine-acetylated products as signature markers for heroin.

Porphyroxine, a trace alkaloid in opium, was identified in the early 1800s and isolated/characterized in the 1960s. Recently, two significant porphyroxine-related byproducts found in the acidic and neutral extracts of illicit heroin were characterized by this laboratory as the N-acetyl-O14 -desmethyl-epi-porphyroxine (B) and N,O8 -diacetyl-O14 -desmethyl-epi-porphyroxine (C). The prevalence of the B and C compounds has been consistent in the following order of abundance for the thousands of authentic heroin samples analyzed: Southwest Asia (SWA)>South America (SA)>Southeast Asia (SEA)>Mexico (MEX). In this research, a rapid and efficient ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to determine the content of porphyroxine and five primary alkaloids (morphine, codeine, thebaine, noscapine, and papaverine) in opium after extraction with methanol/water (50/50). The method was validated in terms of linearity, accuracy, recovery, and precision for porphyroxine. The limit of quantitation (LOQ) for porphyroxine was 2.5ng/mL. The developed method was successfully applied to a total of 114 authentic opium samples from the major poppy-growing regions. The amount of porphyroxine was determined at the level of part per thousand (‰) and the relative concentrations to morphine were in the range of 1x10-4 and 1x10-2 with an order of SWA>SEA, SA>MEX for its average abundance, which is consistent with the order of the average abundance of its acetylated products (B, C) in illicit heroin. This study reveals the significance of porphyroxine and its acylated compounds in classifying heroin and opium samples to major geographical regions of production.

Development and Pharmacokinetics Study of Antifungal Peptide Nanoliposomes by Liquid Chromatography-tandem Mass Spectrometry

Background: The therapeutic ability and application of antifungal peptide (APs) are limited by their physico-chemical and biological properties, the nano-liposomal encapsulation would improve the in vivo circulation and stability. &lt;/P&gt;&lt;P&gt; Objective: To develop a long-circulating liposomal delivery systems encapsulated APs-CGA-N12 with PEGylated lipids and cholesterol, and investigated through in vivo pharmacokinetics. Methods: The liposomes were prepared and characterized, a rapid and simple liquid chromatographytandem mass spectrometry (LC-MS/MS) assay was developed for the determination of antifungal peptide in vivo, the pharmacokinetic characteristics of APs liposomes were evaluated in rats. Results: Liposomes had a large, unilamellar structure, particle size and Zeta potential ranged from 160 to 185 nm and -0.55 to 1.1 mV, respectively. The results indicated that the plasma concentration of peptides in reference solutions rapidly declined after intravenous administration, whereas the liposomeencapsulated ones showed slower elimination. The AUC(0-∞) was increased by 3.0-fold in liposomes in comparison with standard solution (20 mg·kg-1), the half-life (T1/2) was 1.6- and 1.5-fold higher compared to the reference groups of 20 and 40 mg·kg-1, respectively. Conclusion: Therefore, it could be concluded that liposomal encapsulation effectively improved the bioavailability and pharmacokinetic property of antifungal peptides.

Simultaneous determination of calycosin-7-O-β-D-glucoside, cinnamic acid, paeoniflorin and albiflorin in rat plasma by UHPLC-MS/MS and its application to a pharmacokinetic study of Huangqi Guizhi Wuwu Decoction

Huangqi Guizhi Wuwu Decoction (HGWWD), consisting of Radix Astragali, Cinnamomi Ramulus, Paeoniae Radix Alba, Zingiberis Rhizoma Recens and Jujubae Fructus, is a widely used Traditional Chinese Medicine (TCM) formula for the treatment of human blood impediment in China for nearly 2000 years. In order to make good and rational use of this formula in the future, a rapid, sensitive and robust ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for simultaneous determination of calycosin-7-O-β-D-glucoside, cinnamic acid, paeoniflorin and albiflorin, the main active constituents of HGWWD, in rat plasma using geniposide as internal standard (IS). The plasma samples were extracted by protein precipitation with acetonitrile and separated on a Shim-pack XR-ODS C18 column (75 mm × 3.0 mm, 2.2 μm) using gradient elution with a mobile phase consisting of water (containing 0.1% formic acid) and acetonitrile at a flow rate of 0.4 mL/min. Mass spectrometric detection was performed on 3200 QTRAP mass spectrometry equipped with electrospray ionization source in negative ionization mode. Quantification was performed using multiple reaction monitoring (MRM) by monitoring the fragmentation of m/z 491.1→282.9 for calycosin-7-O-β-D-glucoside, m/z147.0→103.1 for cinnamic acid, m/z 525.0→120.9 for paeoniflorin, m/z 525.2→121.0 for albiflorin and m/z 433.1→225.1 for IS, respectively. The method was well validated in terms of linearity, precision, accuracy, recovery, matrix effect and stability. All calibration curves had good linearity (r>0.9977) over the concentration range from 0.1–50 ng/mL for calycosin-7-O-β-D-glycoside, 50–25000 ng/mL for cinnamic acid, 5–2500 ng/mL for paeoniflorin and albiflorin. The intra-day and inter-day precisions (relative standard deviation) were within 11.8%, the accuracy (relative error) ranged from −9.4% to 9.1%, and the lower limit of quantification (LLOQ) were 0.1, 50, 5, 5 ng/mL for calycosin-7-O-β-D-glucoside, cinnamic acid, paeoniflorin and albiflorin, respectively. Extraction recovery, matrix effect and stability were satisfactory in rat plasma. The validated method was successfully applied to a pharmacokinetic study of calycosin-7-O-β-D-glucoside, cinnamic acid, paeoniflorin and albiflorin after oral administration of HGWWD to rats.

Pharmacokinetic Study and Tissue Distribution of Lorlatinib in Mouse Serum and Tissue Samples by Liquid Chromatography-Mass Spectrometry.

In the present study, we developed and validated a rapid and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of lorlatinib in mouse serum and tissue samples, and such a method was successfully applied to investigate the pharmacokinetic study and tissue distribution of lorlatinib after oral administration. Samples were processed with methanol to precipitate protein and extract drugs, and Afatinib-d6 was used as the internal standard (IS). For LC-MS/MS analysis, compounds were separated on a C18 column by gradient elution (0.1% of formic acid and methanol) at 0.5 mL/min in the positive-ion mode with m/z 407.28 [M + H]+ for lorlatinib and m/z 492.10 [M + H]+ for IS. Good linearity was observed within the calibration ranges. Selectivity, accuracy (−6.42% to 8.84%), precision (1.69% to 10.98%), recoveries (91.4% to 115.0%), and matrix effect (84.2% to 110.6%) were all within the acceptable ranges. After oral administration, serum concentration of lorlatinib quickly achieved the maximal concentration (2,705.683 ± 539.779 μg/L) at 0.625 ± 0.231 h. The highest concentration was detected in the liver (3,153.93 ng/100 mg), followed by the stomach (2,159.92 ng/100 mg) and the kidney (548.83 ng/100 mg). In conclusion, a simple and rapid detection method was established and validated for determination of lorlatinib in blood and tissue samples of mouse. The pharmacokinetic study and tissue distribution of lorlatinib were successfully investigated using this method.

LC-MS/MS-based quantification of tryptophan metabolites and neurotransmitters in the serum and brain of mice

l-Tryptophan (Trp) metabolites and related neurotransmitters play crucial roles in physiological functions, and their imbalances are implicated in the pathology of depression, Alzheimer's disease and other diseases. Measurement of Trp metabolites and related neurotransmitters possesses a great potential to elucidate the disease mechanisms and evaluate the outcomes of therapeutic interventions. A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of Trp, l-kynurenine (Kyn), kynurenic acid (Kyna), 3-hydroxykynurenine (3-HK), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), norepinephrine (NE), l-glutamic acid (Glu), γ-aminobutyric acid (GABA) and acetylcholine (ACh) in mice serum and the brain tissues in a single chromatographic run. Samples were spiked with the internal standard, mixed with trifluoroacetic acid to precipitate protein and analyzed by LC-MS/MS. Chromatographic separation was achieved using a Restek Ultra Aqueous C18 column in combination with a gradient elution within 8 min. Mass spectrometric detection was performed using multiple reaction monitoring with electrospray ionization source in positive mode. The method exhibited good selectivity and correlation coefficient values for the calibration curves of each analyte were >0.99. The limit of detection and quantification ranged from 0.96 to 24.48 nmol/L and 3.42 to 244.82 nmol/L, respectively. The intra- and inter-day precision were ≤13.92%. All analytes were stable in prepared samples at room temperature in the autosampler for 24 h. This method was successfully applied to the analysis of biological samples from control and chronic mild stress (CMS) induced depression mice. It was found that Kyn and 3-HK pathways were enhanced by CMS, while the levels of Trp, Kyna, 5-HIAA, Glu, GABA and ACh were significantly reduced. The changes in 5-HT and NE levels were not uniform in the periphery and the brain. This method can therefore be applied to analyze Trp metabolites and related neurotransmitters levels to monitor disease states, study the mechanisms and outcomes of therapeutic interventions.