Rapid Liquid Chromatography-tandem Mass Spectrometry Research Articles

Liquid Chromatography-Tandem Mass Spectrometry Analysis of Riboflavin in Beagle Dog Plasma for Pharmacokinetic Studies

Riboflavin is a water-soluble vitamin, which serves as a precursor to flavin mononucleotide and flavin adenine dinucleotide. This study aimed to develop a simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis for the quantification of riboflavin in the Beagle dog plasma. This method utilized simple protein precipitation with acetonitrile and 13C4,15N2-riboflavin was used as an internal standard (IS). For chromatographic separation, a hydrophilic interaction liquid chromatography (HILIC) column was used with gradient elution. The mobile phase consisted of 0.1% (v/v) aqueous formic acid with 10 mM ammonium formate and acetonitrile with 0.1% (v/v) formic acid. Since riboflavin is an endogenous compound, 4% bovine serum albumin in phosphate buffered saline was used as a surrogate matrix to prepare the calibration curve. The quantification limit for riboflavin in the Beagle dog plasma was 5 ng/mL. The method was fully validated for its specificity, sensitivity, accuracy and precision, recovery, and stability according to the US FDA guidance. The developed LC-MS/MS method may be useful for the in vivo pharmacokinetic studies of riboflavin.

The rapid profiling and simultaneous determination of 12 major alkaloids in Nauclea officinalis by UPLC-Q-TOF-MS and HPLC-ESI-MS/MS.

For the first time, we determined the phytochemical profile of alkaloids from N. officinalis using ultraperformance liquid chromatography-quadrupole-time-of-flight-tandem mass spectrometry (UPLC-Q-TOF-MS/MS). A rapid, specific, and sensitive high-performance liquid chromatography-tandem mass spectrometry method was subsequently developed and fully validated for the simultaneous determination of 12 major alkaloid constituents in N. officinalis: pumiloside; naucleoxoside A; naucleoxoside B; nauclefine; angustidine; angustoline; (3S,19S)-3,14-dihydroangustoline ([α]20D: (-)191°); (3S,19R)-3,14-dihydroangustoline ([α]20D: (-)294.7°); strictosamide; angustine; vincosamide; and 3,14-dihydroangustine. The analytes were detected with an electrospray ionization (ESI) source and multiple reaction monitoring (MRM) using positive scanning mode. Three pairs of epimers (naucleoxoside A and naucleoxoside B; (3S,19S)-3,14-dihydroangustoline ([α]20D: (-)191°) and (3S,19R)-3,14-dihydroangustoline ([α]20D: (-)294.7°); and strictosamide and vincosamide) were successfully separated using an ACQUITY UPLC® BEH C18 column (2.1 mm × 100 mm, 1.7 μm) at 30 °C, with a gradient mobile phase consisting of 0.1% formic acid aqueous solution (A) and acetonitrile (B), a flow rate of 0.2 mL min-1, and a total run time of 30 min. All calibration curves exhibited excellent linear regression (r > 0.999) within the test range. The precision, repeatability, and stability of the method toward the 12 alkaloid compounds were less than 2.0% in terms of the relative standard deviation (RSD) values. The mean recoveries for all compounds were between 98.7% and 101.1%, with RSD values ranging from 0.55% to 1.7% for N. officinalis samples.

Simultaneous LC-MS/MS Determination of Sacubitril, Valsartan and LBQ657 in Human Plasma and Its Application to Clinical Study

A rapid and reproducible liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determine sacubitril, valsartan and a metabolite of sacubitril (LBQ657) in human plasma using sacubitril-d4 and valsartan-d3 as the internal standards. Following protein precipitation, the analytes were operated on an Ultimate® XB-C18 column (2.1 × 50 mm, 3.5 μm, Welch) with a gradient elution with acetonitrile, and 5 mM ammonium acetate and 0.1% formic acid in water as the mobile phase. The detection was performed on a Triple Quad™ 4000 mass spectrometer coupled with an electrospray ionization source (ESI) under positive-ion multiple reaction monitoring mode. The linearities are 2.00-4000, 5.00-10000 and 5.00-10000 ng mL-1 for sacubitril, valsartan and LBQ657, respectively. The accuracy and precision of intra- and inter-day, dilution accuracy, recovery and stability of the method were all within the acceptable limits and no matrix effect or carryover was observed. The suitability of the method was successfully demonstrated in terms of the quantification of sacubitril, valsartan and LBQ657 in plasma samples collected from healthy Chinese volunteers in a clinical trial.

Establishment and Validation of a Liquid Chromatography-Tandem Mass Spectrometry Method for the Determination of Tigecycline in Critically Ill Patients.

Utilizing tigecycline-d9 as an internal standard (IS), we establish and validate a simple, effective, and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitative measurement of tigecycline (TGC) in patient plasma. Acetonitrile was used as a precipitant to process plasma samples by a protein precipitation method. The analyte and IS were separated on an HSS T3 (2.1 × 100 mm, 3.5 μm) chromatographic column using isocratic program with a mobile phase comprising of 80% solvent A (water containing 0.1% formic acid (v/v) with 5 mM ammonium acetate) and 20% solvent B (acetonitrile) with a flow rate of 0.3 mL/min. The mass spectrometer, scanning in multireaction monitoring (MRM) mode and using an electrospray ion source (ESI), operated in the positive-ion mode. The ion pairs used for quantitative analysis were m/z 586.4 ⟶ 513.3 and m/z 595.5 ⟶ 514.3 for TGC and the IS, respectively. The range of the linear calibration curve obtained with this approach was 50–5000 ng/ml. Intra- and interbatch precision for TGC quantitation were less than 7.2%, and the accuracy ranged from 93.4 to 101.8%. The IS-normalized matrix effect was 87 to 104%. Due to its high precision and accuracy, this novel method allows for fast quantitation of TGC with a total analysis time of 2 min. This approach was effectively applied to study the pharmacokinetics of TGC in critically ill adult patients.

Determination of a novel photosensitizer sinoporphyrin sodium in human plasma by ultra-performance liquid chromatography–tandem mass spectrometry

Sinoporphyrin sodium (DVDMS) is a new photosensitizer (PS) and it is used in photodynamic therapy (PDT) against tumor. In this paper, a simple, rapid and specific ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the quantitation of DVDMS in human plasma was developed. The analytes were extracted from plasma samples using liquid-liquid extraction (LLE) after addition of testosterone (internal standard) and chromatographed on an AQUITY UPLC Protein BEH C4 column (50 × 2.1 mm, i.d. 1.7 μm) thermostatted at 40 °C with acetonitrile-water (0.1% formic acid and 0.1 mM K2EDTA) as the gradient mobile phase at flow rate of 0.5 mL/min. The detection was performed on an API 5500 mass spectrometer coupled with electrospray ionization (ESI) source in positive mode. The multiple reactions monitoring (MRM) transitions of m/z 1143.6→563.2 and m/z 289.3→109.1 were used to quantify DVDMS and IS, respectively. The assay was validated over the concentration range of 30−3000 ng/mL. Precision and accuracy are in accordance with the generally accepted criteria for bioanalytical methods. The extraction recovery and the matrix effect were investigated. This method was successfully applied to pharmacokinetic (PK) study of DVDMS in Chinese patients with solid tumor after treated with DVDMS-PDT for the first time.

A UPLC-MS/MS method for determination of endogenous l-carnitine and acetyl-l-carnitine in serum of patients with depression.

A simple, rapid, and selective ultra-performance liquid chromatography-tandem mass spectrometry method for determination of l-carnitine (LC) and acetyl-l-carnitine (ALC) in human serum was developed. Acetyl-l-carnitine-d3 (ALC-d3 ) was selected as internal standard (IS). After protein precipitation with acetonitrile-water (1 mL, 2:1, v/v), the analytes and IS were separated on a 2.5-μm XSelect HSS T3 C18 column by gradient elution with methanol-water (containing 0.01% ammonia water) as the mobile phase at a flow rate of 0.2 mL/min. Analytes were detected with multiple reaction monitoring using a positive scan mode with electrospray ionization. Good linearity (R2 > 0.999) was observed in the concentration range for LC and ALC. The inter- and intra-day values of relative error were -10.4% to 10.0% with CVs less than 9.84%. The average recoveries of the two analytes were 91.29%-98.23%. Blood samples containing LC and ALC were stable under various storage conditions. Normal, haemolytic, and hyperlipidaemic serum had no significant effect on the quantification of LC and ALC. This method was successfully applied to study the concentrations of endogenous LC and ALC in the serum of patients with first-episode depression.

Development of LC-MS/MS determination method and backpropagation artificial neural networks pharmacokinetic model of febuxostat in healthy subjects.

Febuxostat is a well-known drug for treating hyperuricemia and gout. The published methods for determination of febuxostat in human plasma might be unsuitable for high-throughput determination and widespread application. We need to develop a highly selective, sensitive and rapid liquid chromatography-tandem mass spectrometry method. The chromatographic separation was achieved on a Hypersil Gold-C18 (2.1mm×100mm, 1.9μm) column with mobile phase A (Water containing 0.1% formic acid) and mobile phase B (acetonitrile containing 0.1% formic acid). Multiple reaction monitoring (MRM) mode was used for quantification using target ions at m/z 315.3→m/z 271.3 for febuxostat and m/z 324.3→m/z 280.3 for Febuxostat-d9 (IS). A backpropagation artificial neural network (BPANN) pharmacokinetic model was constructed by the data of bioequivalence study. After the LC-MS/MS method validated, it was successfully applied to the bioequivalence study of 30 human volunteers under fed condition. The predicted concentrations generated by BPANN model had a high correlation coefficient with experimental values. A sensitive LC-MS/MS method had been developed and validated for determination of febuxostat in healthy subjects under fed condition, and a BPANN model was developed that can be used to predict the plasma concentration of febuxostat.

Simultaneous determination of YZG-331 and its metabolites in monkey blood by liquid chromatography-tandem mass spectrometry

N6-[(S)-1- (phenyl)-propyl]-adenine riboside (YZG-331) is being developed as a novel sedative and hypnotic agent. The hydroxylated metabolites of YZG-331 have the same mass transition ion pair, making their determination in blood challenging. In this study, a rapid and sensitive liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of YZG-331 and its metabolites M1 (hydrolysis), M2 and M4 (hydrolysis and hydroxylation), M3, M5 and M6 (hydroxylation) in monkey blood. Propranolol was used as the internal standard (IS). Blood samples were prepared using a simple protein precipitation with acetonitrile. The chromatographic separation was performed on an Eclipse Plus C18 column (2.1 × 50 mm, 3.5 μm) at a flow rate of 0.3 mL/min with a gradient mobile phase of methanol/water containing 0.5 % formic acid (v/v). Detection was carried out on a triple quadrupole mass spectrometer in positive ion multiple reaction monitoring mode. The optimized mass transition ion pairs for quantitation were 386→254 for YZG-331, 254→136 for M1, 270→136 for M2 and M4, 402→136 for M3, M5 and M6 and 260→183 for IS. Acceptable linearity was obtained for the analytes over the range of 15−2000 ng/mL for YZG-331, 3−400 ng/mL for M1-M6. The lower limits of the quantification were 15 ng/mL for YZG-331, 3 ng/mL for M1-M6. The intra- and inter-day precisions wre within 10.5 % for all analytes, while the accuracy ranged from -8.3 %-8.8 %. There was no obvious matrix effect and the recoveries of the analytes were 90.6 %–118.2 %. The analytes were proved to be stable during all sample storage, preparation and analytic procedures. The sensitive and rapid LC–MS/MS method for YZG-331 in monkey blood has been applied to pharmacokinetic studies of YZG-331 in monkeys. The oral bioavailability of YZG-331 in monkeys is 74.1 %.

A Sensitive and Rapid LC-MS/MS Method for Quantification of Aminocaproic Acid in Human Plasma and its Pharmacokinetic Application

This paper describes the determination of aminocaproic acid in human plasma by simple, sensitive, and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using aminocaproic D6 acid as the internal standard (ISD). Extraction of aminocaproic acid and ISD was achieved from 200 μL plasma through protein precipitation with acetonitrile. Acetonitrile and 5 mM ammonium acetate buffer in the ratio 60:40 was used as the mobile phase at the flow rate of 1.0 mL/min. The method was developed with a short chromatographic run time of 3.0 min using Ace phenyl column. The retention times of both analyte and ISD were found to be 1.50 ± 0.1 min. The quantification of the separated components was done in positive ion mode by Multiple Reaction Monitoring (MRM) with mass transitions from m/z 132.2 (parent ion) to m/z 79.2 (product ion) for aminocaproic acid and from m/z 138.2 (parent ion) to m/z 74.3 (product ion) for the ISD. The method was validated as per the USFDA guidelines. The linearity was established over the concentration range of 0.3-80 μg/ mL with r2>0.98. The % recovery was 86.69 % and 98.29 %, respectively for aminocaproic acid and ISD. The inter- and intra- day accuracy and precision (%CV) were in the range of 100.91 to 103.80 % and 0.91 to 3.63 %, respectively. The developed method was successfully applied for pharmacokinetic study in twelve healthy adult male subjects under fasting conditions and the results were authenticated by performing incurred sample reanalysis.

A 3-min UPLC-MS/MS method for the simultaneous determination of plasma catecholamines and their metabolites: Method verification and diagnostic efficiency

ObjectiveTo verify a rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the quantification of catecholamines and their metabolites, and to validate its efficiency for the diagnosis of phaeochromocytomas and paragangliomas (PPGLs). MethodsPlasma samples were pretreated with solid-phase extraction, followed by a 3-min UPLC-MS/MS analysis to quantify epinephrine (E), norepinephrine (NE), dopamine (DA), metanephrine (MN), normetanephrine (NMN) and 3-methoxytyramine (3-MT), simultaneously. The UPLC-MS/MS method was comprehensively verified and its diagnostic efficiency on PPGLs was tested using 7 PPGLs and 408 non-PPGLs patient plasma samples. ResultsUsing the developed method, the limit of detections (LODs) of the 6 analytes ranged from 0.0002 nmol/L (MN) to 0.0250 nmol/L (NE), while the lower limit of measuring intervals (LLMIs) ranged from 0.05 nmol/L (E, MN and NMN) to 0.10 nmol/L (NE and DA). The reportable ranges were 0.05–30.00 nmol/L for E, MN and NMN, 0.10–30.00 nmol/L for NE and DA, 1.00–300.00 pg/mL for 3-MT. No significant matrix effect was detected after correcting using internal standard. Besides, intra-day and inter-day precision were also within acceptance criteria with coefficient of variations (CVs) ≤ 15% and recoveries ranged from 95% to 115% for all the 6 analytes. The carryover effect was lower than 10%. Its diagnostic efficiency for PPGLs was significantly increased, the areas under the receiver operating characteristic (ROC) curves were increased from 68.7% to 89.1% (using E, NE and DA) to 75.2%–99.9% (using MN, NMN and 3-MT). ConclusionThis study verified a rapid UPLC-MS/MS method for the determination of catecholamines and their metabolites in human plasma. It showed high diagnostic efficiency and will serve as an important tool to avoid the risk for missing patients with PPGLs.

Assessment of carbonic anhydrase 3 as a marker for meat authenticity and performance of LC-MS/MS for pork content

In recent years, food fraud is a global issue that has raised wide public concern. Mass spectrometry techniques have a significant advantage of qualitatively and quantitatively analyzing food authenticity, especially for highly processed meat products. In this work, a simple and specific, rapid resolution liquid chromatography-tandem mass spectrometry (LC–MS/MS) method was developed and validated for the determination of pork content in processed meat products according to internal standard (ISTD) method. To improve the efficiency of sample preparation, simplified bead-beating and enzymolysis process were investigated. In contrast with different heat-stable and specific porcine-peptides, EPITVSSDQMAK, GGPLTAAYR, HDPSLLPWTASYDPGSAK from Carbonic anhydrase 3 proved to have an excellent quantitative ability, thus obtaining good linear relationship and satisfactory recovery. This method was successfully applied to different types of meat products, thus demonstrating that complex mixtures of pork content can be accurately quantified.

Development of a fast liquid chromatography-tandem mass spectrometry method for simultaneous quantification of neurotransmitters in murine microdialysate

The continuous measurement of multiple neurotransmitters in microdialysate of freely moving mice to study neurochemical changes in specific brain regions requires a rapid and very sensitive quantitative analytical method. The quantitative analysis of 11 neurotransmitters and metabolites, including serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), melatonin (ME), dopamine (DA), levodopa (l-DOPA), 3-methoxytyramine (3-MT), norepinephrine (NE), epinephrine (EP), acetylcholine (ACh), choline (Ch), and γ-aminobutyric acid (GABA), was performed using a biphenyl column coupled to an API-QTrap 3200 (AB SCIEX) mass spectrometer in positive electrospray ionization mode. To the microdialysate samples, 0.5 ng of isotopically labeled standard was added for analyte quantification. A rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous analysis of monoamines, their precursor, and metabolites, as well as ACh, Ch, and GABA in murine microdialysate within 7.0 min. The limit of detection in artificial CSF ranged from 0.005 ng/mL (ME) to 0.75 ng/mL (NE and GABA). A comprehensive pre-analytical protocol was validated. Recovery was between 87 and 117% for neurotransmitter concentrations from 0.6 to 45 ng/mL with an inter-day accuracy of below 20%. Basal neurotransmitter values were determined in the striatum of mice over a time period of 3 h. This LC-MS/MS method, including a short and gentle sample preparation, is suitable for simultaneous measurements of neurotransmitters in murine cerebral microdialysate and enables the determination of basal neurotransmitter levels in specific brain regions to detect disease-related and drug-induced neurochemical changes.Graphical abstract

Pharmacokinetics and tissue distribution study of 15 ingredients of Polygonum chinense Linn extract in rats by UHPLC-MS/MS.

A rapid and sensitive ultrahigh-performance liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous determination of 15 bioactive ingredients in rat plasma and tissues after oral administration of Polygonum chinense Linn extract (PCE). After addition of internal standards (ISs; rutin and danshensu), plasma and tissue samples were pre-treated by protein precipitation with acetonitrile-ethanol. The chromatographic separation was performed on an Agilent ZORBAX RRHD Eclipse Plus C18 column with gradient elution using a mobile phase composed of methanol and water (containing 0.2% acetic acid) at a flow rate of 0.3 mL min-1 . Mass spectrometric detection was carried out using a mass spectrometer in both positive and negative ion electrospray ionization modes by multiple reaction monitoring. The method provided excellent linearity, and the lower limit of quantification range 0.5-30 ng mL-1 for all analytes. The intra- and inter-day precision were less than 9.12% and the accuracy ranged from -4.02% to 6.32%, respectively. The mean extraction recovery and matrix effect of analytes and ISs ranged from 83.65% to 109.20%. The method was successfully applied to the pharmacokinetics and tissue distribution study of 15 ingredients of PCE in rats.

Determination of Organic Acids in Honey by Liquid Chromatography with Tandem Mass Spectrometry

Organic acids in honeys are currently quantified by enzymatic, capillary zone electrophoresis, and chromatographic methods; however, these methods have long analysis times and low sensitivities and selectivities. Here, we developed a simple, rapid liquid chromatography–tandem mass spectrometry (LC-MS/MS)–based method for the determination of organic acids: gluconic acid, tartaric acid, malic acid, citric acid, and succinic acid in honey. First, we evaluated the linearity, matrix effects, detection limits, quantification limits, and repeatability of our method; the limit of detection for organic acids ranged from 0.005 to 0.70 mg/kg. In this study, it was 8 to 31 times higher sensitive than the high-performance liquid chromatography method. We then used our method to determine the concentrations of gluconic acid, tartaric acid, malic acid, citric acid, and succinic acid in 25 honey samples. Gluconic acid was found to account for 64.6 to 99.8% of the total organic acids in the samples. From the correlation and statistical analysis of each component, it is considered that the organic acid is produced by worker bee enzymes such as glucose oxidase and the TCA cycle. The developed method, which has high sensitivity and selectivity, will enable the analysis of more complex and low-concentration components.

Simple and rapid LC-MS/MS method for determination of sitagliptin in human plasma and application to bioequivalence study

A simple, rapid, sensitive, and reproducible liquid chromatography-tandem mass spectrometry method was developed to determine sitagliptin in human plasma. Diphenhydramine HCl was used as internal standard (IS). The chromatographic separation was achieved using Agilent Poroshell 120 EC-C18 – Fast LC column (100 × 2.1mmID, 2.7) fitted with UHPLC Guard Poroshell 120 EC-C18 (5 × 2.1mmID, 2.7 µm). The mobile phase consisted of 0.1% v/v formic acid and methanol (45:55, v/v) run at a flow rate of 0.45 mL/min at 30 °C. Methanol produced relatively cleaner plasma sample as deproteinization agent. Polytetrafluoroethylene membrane was preferred over nylon membrane as the former produced clear plasma samples. The standard calibration curve was linear over the concentration range of 5–500.03 ng/mL. The within-run precision was 0.53–7.12% and accuracy 87.09–105.05%. The between-run precision was 4.74–11.68% and accuracy 95.02–97.36%. The extended run precision was 3.60–6.88% and accuracy 93.18–95.82%. The recovery of analyte and IS was consistent. Sitagliptin in plasma was stable at benchtop (short term) for 24 h, in autosampler tray for 48 h, in instrumentation room for 48 h (post-preparative), after 7 freeze-thaw cycles (−20 ± 10 °C), and 62 days in the freezer (−20 ± 10 °C). Both sitagliptin (analyte) and IS stock solutions were stable for 62 days when kept at room temperature (25 ± 4 °C) and in chiller (2–8 °C). The validated method was successfully applied to a bioequivalence study of two sitagliptin formulations involving 26 healthy Malaysian volunteers.

UPLC-MS/MS Method for Determination of Khasianine in Mouse Blood: Application for Its Pharmacokinetic Study

Background: The aim of this study was to determine the concentrations of khasianine in mouse whole blood sample and its application for the pharmacokinetics by a rapid, selective and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. Methods: The blood samples were preprocessed by one-step protein precipitation with acetonitrile. The study was performed on an ACQUITY I-Class UPLC system with a UPLC BEH column. Lannaconitine (internal standard, IS) and khasianine were gradient eluted by a mixture of acetonitrile and water with 0.1% formic acid at a flow rate of 0.4 mL/min. The mass spectrometer was equipped with an Electrospray Ionization (ESI) source in positive mode. The quantitative detection was performed in a multiple reaction monitoring modes at transitions m/z 722.4→70.7 for khasianine and m/z 585.3→119.9 for the corresponding IS. Results: The calibration curve was of good linearity ranging from 0.5 to 1000 ng/mL (r > 0.995). The Lower Limit of Detection (LLOD) and Lower Limit of Quantitation (LLOQ) were 0.2 and 0.5 ng/mL, respectively. The inter-day and intra-day precision (RSD%) were both less than 14%, and the accuracy ranged from 86.6% to 108.3%. The matrix effects were between 98.0% and 103.7%, and the average recovery was better than 67.4%. Conclusion: This assay established a sensitive, rapid, selective UPLC-MS/MS method which was successfully used for the pharmacokinetic study of khasianine in mouse blood, and the absolute availability of khasianine was 0.78% which exhibited a poor oral absorption.

Development of a Diagnostic Screening Strategy for Niemann-Pick Diseases Based on Simultaneous Liquid Chromatography-Tandem Mass Spectrometry Analyses of N-Palmitoyl-O-phosphocholine-serine and Sphingosylphosphorylcholine.

Early diagnosis of Niemann-Pick diseases (NPDs) is important for better prognosis of such diseases. N-Palmitoyl-O-phosphocholine-serine (PPCS) is a new NPD biomarker possessing high sensitivity, and with its combination with sphingosylphosphocholine (SPC) it may be possible to distinguish NPD-C from NPD-A/B. In this study, a rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method (method 1) and a validated LC-MS/MS analysis (method 2) of PPCS and SPC were developed, and we have proposed a diagnostic screening strategy for NPDs using a combination of serum PPCS and SPC concentrations. Nexera and API 5000 were used as LC-MS/MS systems. C18 columns with lengths of 10 and 50 mm were used for method 1 and 2, respectively. 2H3-Labeled PPCS and nor-SPC were used as internal standards. Selective reaction monitoring in positive-ion mode was used for MS/MS. Run times of 1.2 and 8 min were set for methods 1 and 2, respectively. In both methods 1 and 2, two analytes showed high linearity in the range of 1-4000 ng/mL. Method 2 provided high accuracy and precision in method validation. Serum concentrations of both analytes were significantly higher in NPD-C patients than those of healthy subjects in both methods. Serum PPCS correlated between methods 1 and 2; however, it was different in the case of SPC. The serum PPCS/SPC ratio was different in healthy subjects, NPD-C, and NPD-A/B. These results suggest that using a combination of the two LC-MS/MS analytical methods for PPCS and SPC is useful for diagnostic screening of NPDs.

Multi-Component Comparative Pharmacokinetics in Rats After Oral Administration of Fructus aurantii Extract, Naringin, Neohesperidin, and Naringin-Neohesperidin.

Citrus × aurantium L., Chinese name: Fructus Aurantii (FA) has been largely used as Qi-invigorating herb in China for centuries. The main components (meranzin hydrate, naringin, neohesperidin, meranzin, nobiletin) have good physiological activity with relatively high abundance in FA. Few multi-component comparative pharmacokinetics are simultaneously accessible for the flavone glycosides, polymethoxy flavones, and coumarins in FA. In this work, a reliable and rapid ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established and validated to determine the five ingredients in the SD rat plasma, and further applied to the pharmacokinetic studies after oral administration of monomer, drugs in compatibility, and FA extract. After hydrolysis with β-glucuronidase and sulfatase, the concentration of naringin and neohesperidin in rat plasma were expressed respectively by the total concentration of naringenin and hesperitin which was determined by UPLC-MS/MS. Double-peak phenomenon was observed for naringin and neohesperidin, which may be due to the enterohepatic circulation or multiple site absorption of the two flavone glycosides. Meranzin hydrate and meranzin (coumarins) were absorbed rapidly (Tmax, about 1.0 h) but eliminated slowly (t1/2z exceeds 6.5 h). Nobiletin, a typical polymethoxy flavone, was also rapidly absorbed according to Tmax and AUC(0-t). DAS 3.1 software suggests the pharmacokinetic profiles of the five components in rats be depicted as a two-compartment pharmacokinetic model. There were significant differences in pharmacokinetic parameters for naringenin and hesperetin between the compatibility, FA extract group vs monomer group: ① remarkable increases in the values of AUC(0–∞), AUC(0–t) and Cmax; ② obvious decrease of CLZ/F; and ③ longer tmax and t1/2z. The results suggest that compatibility can promote mutual absorption and affect the elimination behaviors.

Development and validation of LC-MS/MS method with QuEChERS clean-up for detecting cannabinoids in foods and dietary supplements

ABSTRACT a rapid and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) clean-up for a variety of foods and dietary supplements (DS). QuEChERS is widely used in extraction or clean-up procedures to eliminate interference of matrices such as sugars, organic acids, lipids, and fatty acids. The samples were categorised into three types, and various pretreatment methods were compared for each type. In all types, the QuEChERS was superior and selected as the final pretreatment method. The optimised method was validated for specificity, limit of detection (LOD), limit of quantification (LOQ), linearity, recovery, precision and accuracy. All of the validation results met the requirements of the international guidelines for all types of samples. The validated method was applied to 30 commercial food samples, CBD was detected in 17 samples, with 2 of them detected below the LOQ level and the rest detected in a range of 70 μg/kg to 31305 mg/kg (3.1%, w/w). Meanwhile, THC was detected in 14 samples; 2 of them were detected below the LOQ level and the rest detected in a 0.08–98.62 μg/g range. These results indicated that the validated method can be successfully applied for the determination of cannabinoids in a variety of samples. Furthermore, it will be useful for controlling the illegal distribution of cannabinoids.

Network pharmacology strategy for revealing the pharmacological mechanism of pharmacokinetic target components of San-Ye-Tang-Zhi-Qing formula for the treatment of type 2 diabetes mellitus

Ethnopharmacological relevanceSan-Ye-Tang-Zhi-Qing formula (SYTZQ) is an effective prescription for the treatment of pre-diabetes disorders of glycolipid metabolism in type 2 diabetes mellitus (T2DM). It consists of five Chinese herbs including Mori Folium, Nelumbinis Folium, Crataegi Folium, Salviae Miltiorrhizae Radix et Rhizoma and Paeoniae Radix Rubra. Aim of the studyThis study was aimed to reveal the pharmacological mechanism of pharmacokinetic target components of SYTZQ for the treatment of T2DM. Materials and methodsA rapid, precise and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to quantify simultaneously nuciferin, vitexin-4″-O-glucoside, vitexin-2″-O-rhamnoside, paeoniflorin and rosmarinic acid in rat plasma after oral administration of SYTZQ. The network pharmacology was used to analyze the effect of the compounds absorbed into the blood of SYTZQ on T2DM. The effects of paeoniflorin, nuciferine and rosmarinic acid on adipogenic differentiation were validated in vitro experiments. ResultsThe separation was performed on an ACQUITY UHPLC HSS T3 column (2.1 mm × 100 mm, 1.7 μm) using acetonitrile and 0.1% (v/v) formic acid in water as the mobile phase in gradient elution. The calibration curves of five analytes showed good linearity (r ≥ 0.9991) with the lower limits of quantification (LLOQ) between 0.3 and 5.0 ng/mL. The recoveries and matrix effects of five analytes ranged from 81.1% to 113%. The RSDs of inter-day and intra-day precision were all within 13.7%. The validated method was successfully applied to the pharmacokinetic study of five ingredients after oral administration of SYTZQ to rat. 39 major targets and 22 candidate pathways of five compounds absorbed into the blood of rats after administration of SYTZQ were identified and successfully constructed a compound-target-disease-pathway network. It was confirmed that paeniforin, nuciferine and rosmarinic acid could decrease the adipogenicity differentiation in vitro experiments. ConclusionsThe pharmacokinetic parameters indicated that the five components (nuciferin, vitexin-4″-O-glucoside, vitexin-2″-O-rhamnoside, paeoniflorin and rosmarinic acid) were absorbed and eliminated quickly in vivo. These five absorbed components were associated with 22 pathways, including insulin resistance, regulation of lipolysis in adipocytes, PI3k/AKT-, TNF-, cAMP- and cGMP-PKG-signaling pathway. Paeoniflorin, nuciferine and rosmarinic acid have the effect of inhibiting adipocyte differentiation. This study could provide more reference for quality control, and provide a firm basis for evaluating the clinical efficiency of SYTZQ.