LC-tandem Mass Spectrometry Method Research Articles

Development and validation of a liquid chromatography-tandem mass spectrometry method for simultaneous quantification of eight Xiakucao Oral liquid-related compounds in rat plasma and its application in pharmacokinetic study.

Xiakucao Oral Liquid (XKCOL) has been widely used for treating mammary gland hyperplasia and goiter in China. However, its pharmacokinetic data have been missing to date. To conduct its pharmacokinetic study, we established an LC-tandem mass spectrometry method for the simultaneous determination of eight XKCOL-related compounds in rat plasma. Liquid-liquid extraction was used for the sampling process. Chromatographic separation was performed on a Phenomenon Luna C18 column with a mobile phase of methanol and 2 mM ammonium acetate, using gradient elution at a flow rate of 0.8 mL/min. Detection was performed in the multiple reaction monitoring mode using negative electrospray ionization (ESI-) with optimized MS parameters. Endogenous substances and carryover did not interfere in the detection of analytes. The calibration curves showed a good linear relationship within the linear ranges. The intra- and inter-batch accuracy and precision were 94.8%-110.0% and ≤11.2%, respectively. There was no significant matrix effect and the recovery was reproducible. The dilution of samples did not affect the accuracy and precision. The solution and plasma samples were stable under the various test conditions. The major components of XKCOL absorbed into the blood were salvianic acid A and rosmarinic acid. They demonstrated linear kinetics over the dose range used in this study.

Pharmacokinetic and oral bioavailability study of schaftoside in rats.

A simple and sensitive LC-tandem mass spectrometry method was established and validated for the determination of schaftoside in rat plasma. After prepared by protein precipitation with acetonitrile, schaftoside and internal standard were separated on a Waters HSS T3 column using acetonitrile containing 0.1% formic acid and 0.1% formic acid in water as the mobile phase by gradient elution. The method showed excellent linearity over the range of 0.5-500 ng/mL with acceptable intra- and inter-day precision, accuracy, matrix effect, and recovery. The stability assay indicated that schaftoside was stable during the sample acquisition, preparation, and storage. The method was applied to a pharmacokinetic study of schaftoside in rats. The result suggested that after intravenous administration at a dose of 1 mg/kg, schaftoside was quickly eliminated from the plasma with an elimination half-life of 0.58 h. After oral administration at doses of 5, 10, and 20 mg/kg, schaftoside was quickly absorbed into the plasma and reached the peak concentration (Cmax) of 45.1-104.99 ng/mL at 0.67-1.17 h. The increase of exposure (area under the curve) was linear with the increase of dose. The oral bioavailability was 0.42%-0.71% in the range of 5-20 mg/kg.

Development and validation of a liquid chromatography-tandem mass spectrometry method for the quantification of the acetyl-coenzyme A competitive p300/CBP catalytic inhibitor A-485 in biological samples.

The small molecule A-485 competitively inhibits the histone acetyltransferase domain of CBP (cyclic-adenosine monophosphate response element-binding protein)/p300. Apart from its antineoplastic activity, researchers are exploring its potential benefits in treating osteoporosis and its impact on energy metabolism. However, so far, only limited pharmacokinetic data are available, and the crucial determination of A-485 concentration in various biological materials with small sample volumes remains unpublished. A rapid and sensitive LC-tandem mass spectrometry method has been developed and validated to quantify A-485 in mouse serum and tissue. In this method, serum samples underwent precipitation with acetonitrile, while cell lysates were appropriately diluted. The determination of A-485 utilized a reversed-phase column with a mobile phase gradient, and detection was carried out in multiple reaction monitoring mode. The lower standard sample, with a concentration of 7.8 ng/mL, served as the lower limit of quantification, while the upper standard was established at 1000 ng/mL. A-485 concentrations were assessed in both serum samples and the lysate of all examined tissues, revealing swift metabolic clearance. The analytical method outlined here is deemed appropriate for subsequent studies. The ability to measure the active ingredient in various compartments facilitates the determination of accurate pharmacokinetic parameters. In the event of human use of A-485, the analysis method can be seamlessly transferred to human samples.

A simple and rapid LC-MS/MS method for the simultaneous determination of 15 bile acids in human serum and its application to patients with decompensated cirrhosis.

Liver cirrhosis is currently the twelfth leading cause of death globally and the sixth leading cause of death in China. Its treatment is expensive. Changes in the composition of the serum bile acid pool are sensitive indicators of the severity of liver cirrhosis. In this study, a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and used to simultaneously determine 15 bile acids in human serum in patients with decompensated cirrhosis. Sample preparation involved spiking with isotope internal standards (ISs) followed by protein precipitation and the analytical run time was 5 min. The LC-MS/MS method was fully validated according to CLSI C62A and the Consensus of method development and validation of liquid chromatography-tandem mass spectrometry in clinical laboratories. The method achieved an acceptable coefficient of variation for precision (0.83-14.80%) and accuracy (89.39-107.62%). Finally, as proof of applicability, the method was applied to patients with decompensated cirrhosis in routine clinical sample analysis. The degree of variation of different bile acids was clearly shown. These results indicated that abnormal metabolic pathways might play important roles in decompensated cirrhosis.

Development of a Simultaneous Liquid Chromatography-Tandem Mass Spectrometry Analytical Method for Urinary Endogenous Substrates and Metabolites for Predicting Cytochrome P450 3A4 Activity.

CYP3A4, which contributes to the metabolism of more than 30% of clinically used drugs, exhibits high variation in its activity; therefore, predicting CYP3A4 activity before drug treatment is vital for determining the optimal dosage for each patient. We aimed to develop and validate an LC-tandem mass spectrometry (LC-MS/MS) method that simultaneously measures the levels of CYP3A4 activity-related predictive biomarkers (6β-hydroxycortisol (6β-OHC), cortisol (C), 1β-hydroxydeoxycholic acid (1β-OHDCA), and deoxycholic acid (DCA)). Chromatographic separation was achieved using a YMC-Triart C18 column and a gradient flow of the mobile phase comprising deionized water/25% ammonia solution (100 : 0.1, v/v) and methanol/acetonitrile/25% ammonia solution (50 : 50 : 0.1, v/v/v). Selective reaction monitoring in the negative-ion mode was used for MS/MS, and run times of 33 min were used. All analytes showed high linearity in the range of 3-3000 ng/mL. Additionally, their concentrations in urine samples derived from volunteers were analyzed via treatment with deconjugation enzymes, ignoring inter-individual differences in the variation of other enzymatic activities. Our method satisfied the analytical validation criteria under clinical conditions. Moreover, the concentrations of each analyte were quantified within the range of calibration curves for all urine samples. The conjugated forms of each analyte were hydrolyzed to accurately examine CYP3A4 activity. Non-invasive urine sampling employed herein is an effective alternative to invasive plasma sampling. The analytically validated simultaneous quantification method developed in this study can be used to predict CYP3A4 activity in precision medicine and investigate the potential clinical applications of CYP3A4 biomarkers (6β-OHC/C and 1β-OHDCA/DCA ratios).

Quantitation of navtemadlin in human plasma and brain tissue by liquid chromatography-tandem mass spectrometry.

Navtemadlin is an orally bioavailable small molecule that blocks the protein-protein interaction between murine double minute 2 protein (MDM2) and the tumor suppressor protein p53, leading to p53-mediated cell cycle arrest and apoptosis. It is being evaluated in clinical trials for a variety of malignancies, both as a single agent and in combination regimens. A sensitive, robust LC-tandem mass spectrometry (LC-MS/MS) method was developed to quantitate navtemadlin in plasma, and this method was also validated using brain tissue homogenate. Sample preparation involved protein precipitation of plasma or brain tissue homogenate using acetonitrile. Navtemadlin, navtemadlin glucuronide, and the internal standard, D6 -navtemadlin, were separated from microsomal incubation extracts using gradient elution and a ZORBAX XDB C18 column. Analytes were detected using a SCIEX 5500 triple quadrupole mass spectrometer in positive electrospray ionization mode. The assay range of 1-1000 ng/mL was shown to be accurate (96.1-102.0% and 95.7-104%) and precise (coefficient of variation ≤ 10.6% and ≤ 6.6%) in plasma and brain tissue homogenate, respectively. An 8000 ng/mL navtemadlin sample diluted 1:10 (v/v) with plasma was also accurately quantitated. Navtemadlin has been stable in frozen plasma at -70°C for at least 20 months. This validated LC-MS/MS method was applied to determine navtemadlin concentrations in plasma and brain tissue samples from two separate patients receiving 120 mg/day navtemadlin on protocol ABTC1604.

Validated liquid chromatography-tandem mass spectrometry method for simultaneous quantitation of bendamustine and copanlisib in mouse plasma: Application to a pharmacokinetic study in mice.

In this study, we report the development and validation of an LC-tandem mass spectrometry method for the simultaneous quantitation of bendamustine and copanlisib in mouse plasma as per the US FDA regulatory guidelines. The sample processing involves extraction of bendamustine and copanlisib along with internal standard (IS; warfarin) from 50 μL mouse plasma using a liquid-liquid extraction method. The chromatographic separation of bendamustine, copanlisib and the IS was achieved on an Atlantis dC18 column using an isocratic mobile phase (5 mM ammonium acetate:methanol, 20:80 v/v). Bendamustine, copanlisib and the IS eluted at 0.88, 1.39 and 0.74 min, respectively, with a total run time of 2.5 min. The calibration curve ranged from 3.99-2996 and 4.33-3248 ng/mL for bendamustine and copanlisib, respectively. Inter- and intra-day precision and accuracy, stability in processed samples and upon storage, dilution integrity and incurred sample reanalysis were investigated for both the analytes. The intra- and inter-day precisions were in the ranges of 2.01%-5.05% and 2.74%-6.13% and 1.98%-7.64 and 8.62%-9.04% for bendamustine and copanlisib, respectively. Stability studies showed that both analytes were stable on bench top for 6 h, in auto-sampler for 24 and at -80°C for 30 days. The validated method was successfully applied to a pharmacokinetic study in mice.

A Simple and Sensitive LC-MS/MS Method for Determination and Quantification of Potential Genotoxic Impurities in the Vismodegib Active Pharmaceutical Ingredient

A rapid and sensitive LC-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantitative analysis of four potential genotoxic impurities Imp-A (2-chloro-5-nitroaniline), Imp-B (1-chloro-2-iodo-4-nitrobenzene), Imp-C (1-(2-chloro-5-nitrophenyl)ethan-1-one) and Imp-D (2-chloro-5-nitrobenzoic acid) in Vismodegib API drug sample. This trace analysis was achieved on CSH C18, 15.0 cm x 3.0 mm, 1.7 micron column maintained at 45°C. Optimal mobile phase consisted of 0.05% formic acid in water was used as mobile phase A and acetonitrile used as mobile phase B in gradient mode with the flow rate of 0.5 mL/min. The developed method had the short run time of 12 minutes. Quantification of four potential genotoxic impurities were carried out using mass detection with electrospray ionization in multiple reaction monitoring mode. The method was linear in the range of 0.03 ppm to 1.50 ppm for four potential genotoxic impurities with a correlation coefficient not less than 0.999. The recoveries were found satisfactory over the range between 96.67 and 106.90% for all selected impurities. The developed method was able to quantitate all four PGIs at a concentration level of 0.03 ppm (0.03 ppm with respect to 20 mg /mL Vismodegib).

Determination of nootkatone in rat plasma by LC-tandem mass spectrometry and its application in a pharmacokinetic study.

This study aimed to develop a rapid, sensitive, and specific LC-tandem mass spectrometry method for the determination of nootkatone in rat plasma. α-Cyperone was chosen as the internal standard (IS). The plasma was processed using a one-step acetonitrile protein precipitation method. Chromatographic separation of nootkatone was achieved on a Phenomenex Kinetex XB-C18 column (2.10 × 50 mm, 2.6μm) at 35°C with a mobile phase consisting of acetonitrile and water under a gradient elution at a flow rate of 0.35 mL/min. An electrospray ionization source was applied and operated in positive ion and multiple reaction monitoring modes. Nootkatone and IS were quantified using the transitions of m/z 219.200 → 163.110 and m/z 219.200 → 111.000, respectively. The calibration curves were linear over the range of 10-2000 ng/mL (r = 0.9943). The lower limit of quantification was 10ng/mL. The intra- and inter-day precision (relative standard deviation) ranged from 2.56% to 8.41%, with the accuracy values ranging from 98.9% to 99.17% for four different concentration levels. The matrix effect and extraction recovery were within acceptable limits. The validated method was successfully applied to the pharmacokinetic study of nootkatone in rats after oral and intravenous administration at three dosages. The main pharmacokinetic parameters were calculated, showing low bioavailability of nootkatone.

Comparative pharmacokinetic and bioavailability study of lobetyolin in rats after administration of lobetyolin and Codonopsis pilosula extract by ultra-performance LC-tandem mass spectrometry.

Codonopsis pilosula (CP) is a traditional Chinese medicine used to invigorate spleen, replenish lung, nourish blood and engender fluid. A rapid, selective and sensitive ultra-performance LC-tandem mass spectrometry method was developed and validated to determine lobetyolin in rat plasma. The calibration curve showed good linearity over a concentration range of 0.46-1000 ng/mL for lobetyolin. The extraction recovery ranged from 72.5% to 89.1% with matrix effects of 81.6%-107.8%. The intra- and inter-batch precision and accuracy were 0.02-14.4% and -13.9%to -1.36%, respectively. The method was successfully applied for the bioavailability study of lobetyolin in rats after oral administration of pure lobetyolin and CP extract. Results showed that the elimination half-time (t1/2 ) and the area under the concentration-time curve from zero to infinity of lobetyolin in CP extract were statistically different from those of the pure monomer (P < 0.05). However, the time to reach the maximum plasma concentration (Tmax ) and the maximum concentration (Cmax ) showed no significant differences between the two treatments. Furthermore, the bioavailability of lobetyolin in the experimental group was only 3.90%, significantly lower than that of the CP extract group (6.97%). The low bioavailability indicated that this component may be absorbed poorly or metabolized extensively in rats. Our results will provide useful information for further preclinical studies and formulation preparation of lobetyolin.

Simultaneous determination of sacubitrilat and fimasartan in rat plasma by a triple quad liquid chromatography-tandem mass spectrometry method utilizing electrospray ionization in positive mode.

An LC-tandem mass spectrometry method was developed and validated for the simultaneous quantitation of fimasartan and sacubitrilat using positive ion mode. The protein precipitation method was employed for the extraction of fimasartan, sacubitrilat and alprazolam (internal standard) from rat heparinized plasma. Baseline separation of the analytes was accomplished using an ACE-5, C18 (4.6 × 50 mm) column and gradient elution of mobile phase A (5 mm ammonium formate and 0.1% formic acid in purified water) and B (acetonitrile:methanol, 80:20; v/v). All peaks of interest were eluted within a 5-min runtime. The quantitation was achieved in the selected reaction monitoring mode. The developed method was validated as per US Food and Drug Administration guidelines and met the pre-defined acceptance criteria. The method showed linearity from 5 to 10,000 ng/mL. The accuracy/precision of intra- and inter-batch assays was 96.64%/2.05% to 109.17%/13.70% and 100.74%/3.76% to 106.39%/9.75% for fimasartan and 100.02%/1.49% to 113.80%/9.38% and 100.75%/2.31% to 108.40%/7.74% for sacubitrilat, respectively, in rat plasma. Fimasartan and sacubitrilat remained stable in rat plasma at different experimental conditions up to 21 days. The developed method was sensitive, selective and applied successfully to monitor plasma concentrations of fimasartan and sacubitrilat in an oral rat pharmacokinetic study.

Method development and validation for simultaneous determination of ebastine and its active metabolite carebastine in human plasma by liquid chromatography-tandem mass spectrometry and its application to a clinical pharmacokinetic study in healthy Chinese volunteers.

A simple LC-tandem mass spectrometry (MS/MS) method to determine ebastine and carebastine (active metabolite) in human plasma was developed and validated. Analytes and internal standards were precipitated by protein precipitation and separated on Synergi Hydro-RP 80A column (4 μm, 50 mm × 2.0 mm; Phenomenex) by gradient elution with mobile phase A comprising 0.1% formic acid in 5 mm ammonium acetate (NH4 Ac) and B comprising 100% methanol at a flow rate 0.4 mL/min. Ions were detected in positive multiple reaction monitoring mode, and they exhibited linearity over concentration range 0.01-8.0 and 1.00-300 ng/mL for ebastine and carebastine, respectively. A clinical pharmacokinetic study was conducted in healthy Chinese volunteers under fasting and fed conditions after a single oral administration of 10 mg ebastine. The maximum plasma concentration (Cmax ), time to Cmax (Tmax ) and elimination half-life for ebastine were 0.679 ± 0.762 ng/mL, 1.67 ± 1.43 h and 7.86 ± 6.18 h, respectively, whereas these for carebastine were 143 ± 68.4 ng/mL, 5.00 ± 2.00 h and 17.4 ± 4.97 h, respectively under fasting conditions; the corresponding values under fed conditions were 4.13 ± 2.53 ng/mL, 3.18 ± 1.09 h and 21.6 ± 7.77 h for ebastine and 176 ± 68.4 ng/mL, 6.14 ± 2.0 h and 20.0 ± 4.97 h for carebastine.

Simultaneous quantitative determination of liraglutide and insulin degludec in rat plasma by liquid chromatography-tandem mass spectrometry method and its application.

A simple, fast and high-throughput LC-tandem mass spectrometry method was developed and validated to simultaneously measure liraglutide and insulin degludec in rat plasma. After protein precipitation, plasma samples were subjected to gradient elution using an InertSustain Bio C18 column with 1000/20/1 water/acetonitrile/formic acid (v/v/v) and 1000/1 acetonitrile/formic acid (v/v) as the mobile phase. The method was validated from 1.00 to 500 ng/mL of liraglutide and insulin degludec. Further, the extraction recovery from the plasma was 41.8%-49.2% for liraglutide and 56.5%-69.7% for insulin degludec. Intra- and inter-day precision of liraglutide was 3.5%-9.4% and 8.4%-9.8%, respectively, whereas its accuracy was between -12.6% and -1.3%. Intra- and inter-day precision of insulin degludec was 5.2%-13.6% and 11.8%-19.1%, respectively, showing an accuracy between -3.0% and 9.9%. As a result, the method was successfully applied to a pharmacokinetics study of liraglutide and insulin degludec following a single-dose subcutaneous administration to rats.

A simplified and reliable LC-tandem mass spectrometry method for determination of ulipristal acetate in human plasma and its application to a pharmacokinetic study in healthy Chinese volunteers.

In this study, a simplified, sensitive and reliable LC-tandem mass spectrometry method was established and validated for the quantification of ulipristal acetate (UPA) in human plasma and for the investigation of pharmacokinetic profile of UPA following a single oral administration of ella (UPA 30-mg tablet) in healthy Chinese volunteers. Plasma samples were analyzed after being processed by protein precipitation with methanol. Chromatographic separation was performed on a Kinetex EVO C18 column (2.1 × 50 mm, 2.6 μm) using gradient elution with a mobile phase composed of methanol and water containing 2 mm ammonium acetate and 0.3% formic acid at a flow rate of 0.3 mL/min. The chromatographic running time was 4.0 min per sample. The MS detection was performed via an LC system with the positive ion electrospray ionization interface in multiple reaction monitoring mode using the transition of m/z 476.2 → 134.1 for UPA and m/z 479.3 → 416.2 for UPA-d3 [internal standard (IS)], respectively. UPA and IS were monitored without severe interference from the biological matrices. The method was linear over the wide concentration range of 0.300-300 ng/mL. The intra- and inter-day precision and accuracy were well within the limits required for bioanalytical assays. The method was first used to describe the pharmacokinetic characteristic of UPA after a single oral administration of ella in healthy Chinese volunteers. Based on a between-study comparison, there were statistically significant differences (p < .05) between Chinese and Caucasian volunteers for the systemic exposure of UPA, suggesting that race seems to significantly impact the systemic exposure of UPA.

In vitro metabolism of 2'-ribose unmodified and modified phosphorothioate oligonucleotide therapeutics using liquid chromatography mass spectrometry.

Antisense oligonucleotides (ASOs) have been touted as an emerging therapeutic class to treat genetic disorders and infections. The evaluation of metabolic stability of ASOs during biotransformation is critical due to concerns regarding drug safety. Because the effects of the modifications in ASOs on their metabolic stabilities are different from unmodified ASOs, studies that afford an understanding of these effects as well as propose proper methods to determine modified and unmodified ASO metabolites are imperative. An LC-tandem mass spectrometry method offering good selectivity with a high-quality separation using 30 mm N,N-dimethylcyclohexylamine and 100 mm 1,1,1,3,3,3-hexafluoro-2-propanol was utilized to identify each oligonucleotide metabolite. Subsequently, the method was successfully applied to a variety of in vitro systems including endo/exonuclease digestion, mouse liver homogenates, and then liver microsomes, after which the metabolic stability of unmodified versus modified ASOs was compared. Typical patterns of chain-shortened metabolites generated by mainly 3'-exonucleases were observed in phosphodiester and phosphorothioate ASOs, and endonuclease activity was identically observed in gapmers that showed relatively more resistance to nuclease degradation. Overall, the degradation of each ASO occurred more slowly corresponding to the degree of chemical modifications, while 5'-exonuclease activities were only observed in gapmers incubated in mouse liver homogenates. Our findings provide further understanding of the impact of modifications on the metabolic stability of ASOs, which facilitates the development of future ASO therapeutics.

Evaluation of pharmacokinetics, bioavailability and urinary excretion of scopolin and its metabolite scopoletin in Sprague Dawley rats by liquid chromatography-tandem mass spectrometry.

We aimed to investigate the pharmacokinetics, bioavailability and urinary excretion of scopolin and its metabolite scopoletin in rats. An LC-tandem mass spectrometry (MS/MS) method for simultaneous determination of scopolin and scopoletin in rat biomatrices was developed and validated over a plasma and urine concentration range of 5.0-2000 ng/mL. Chromatographic separation was performed on a Hypersil GOLD C18 column with acetonitrile and 0.1% formic acid in water as mobile phase with gradient elution. Detection was performed in the positive ionization and selected reaction monitoring mode. The intra- and inter-batch precision and accuracy, extraction recovery and matrix effect and stability of scopolin and scopoletin were well within the acceptable limits of variation. There was no gender-related difference in the pharmacokinetic profiles of scopolin. There were significant differences in total area under the concentration-time curve (AUC), time required to achieve a maximal concentration (Tmax ) and apparent clearance from plasma (Cl/F) of scopoletin between the male and female rats (p < .05). The bioavailability (F) of scopolin was exceptionally low. The maximal excretion rates were 7.61 μg/h and 7.15 μg/h for scopolin and 31.68 μg/h and 25.58 μg/h for scopoletin in male and female rats, respectively. The LC-MS/MS method was successfully applied to the pharmacokinetic, bioavailability and urinary excretion studies of scopolin and its metabolite scopoletin following a single administration of scopolin to rats.

Practical liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of amitriptyline, nortriptyline and their hydroxy metabolites in human serum.

Amitriptyline (AMI) has been in use for decades in treating depression and more recently for the management of neuropathic pain. A highly sensitive and specific LC-tandem mass spectrometry method was developed for simultaneous determination of AMI, its active metabolite nortriptyline (NOR) and their hydroxy-metabolites in human serum, using deuterated AMI and NOR as internal standards. The isobaric E-10-hydroxyamitriptyline (E-OH AMI), Z-10-hydroxyamitriptyline (Z-OH AMI), E-10-hydroxynortriptyline (E-OH NOR) and Z-10-hydroxynortriptyline (Z-OH NOR), together with their parent compounds, were separated on an ACE C18 column using a simple protein precipitation method, followed by dilution and analysis using positive electrospray ionisation with multiple reaction monitoring. The total run time was 6 min with elution of E-OH AMI, E-OH NOR, Z-OH AMI, Z-OH NOR, AMI (+ deuterated AMI) and NOR (+ deuterated NOR) at 1.21, 1.28, 1.66, 1.71, 2.50 and 2.59 min, respectively. The method was validated in human serum with a lower limit of quantitation of 0.5 ng/mL for all analytes. A linear response function was established for the range of concentrations 0.5-400 ng/mL (r2 > .999). The practical assay was applied on samples from patients on AMI, genotyped for CYP2C19 and CYP2D6, to understand the influence of metaboliser status and concomitant medication on therapeutic drug monitoring.

Simultaneous Quantification of Five Flavanone Glycosides in Rat Plasma by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry: Application to a Comparative Pharmacokinetic Study of Aurantii Fructus Immaturus and Aurantii Fructus Extracts

Background: Aurantii Fructus Immaturus (AFI) and Aurantii Fructus (AF) are two traditional citrus herbs with health-promoting and nutritive properties. Objective: This paper presents the first attempt to simultaneously investigate the absorption of five major flavanone glycosides, namely narirutin, naringin, hesperidin, neohesperidin, and poncirin, in rat plasma following a single oral administration of AFI and AF extracts to rats. Methods: The plasma concentrations were determined by liquid-liquid extraction followed by a rapid and sensitive ultra-performance LC-tandem mass spectrometry method. Pharmacokinetic parameters were analyzed by noncompartmental modeling using DAS software. Results: The developed method was validated and successfully applied to the pharmacokinetic study of these five flavanone glycosides. Conclusions: The comparison of the pharmacokinetic parameters of flavanone glycosides showed that the absorption of AF extract was lower, while the elimination was relatively rapid, compared with those of AFI extract. Highlights: This study may be useful for further utilization of these two citrus herbs.

Development of an LC⁻Tandem Mass Spectrometry Method for the Quantitative Analysis of Hercynine in Human Whole Blood.

Given that the peculiar redox behavior of ergothioneine involves a rapid regeneration process, the measurement of its precursor and redox metabolite hercynine could be particularly useful in assessing its role in oxidative stress or other biological processes. Thus, a LC-MS/MS method for the determination of hercynine concentrations in whole blood was developed. After lysis of red blood cells by cold water, samples were filtered on micro concentrators at a controlled temperature of 4 °C. The clear filtered fluid was then treated with diethylpyrocarbonate to derivatize hercynine for the analysis by LC-MS/MS. The derivatized analyte was isocratically separated as a carbethoxy derivative on a C18 column with a mobile phase of an aqueous 0.1% v/v formic acid and acetonitrile (95:5). Effluents were monitored by MRM transitions at m/z 270.28→95 and 273.21→95 for hercynine and its deuterated counterpart, respectively. No cross-talk between MRM transitions was observed and a good linearity was found within a range of 35–1120 nmol/L. The LOD and LOQ were, respectively, 10.30 and 31.21 nmol/L with an intraday and intermediate precision below 7%. The average hercynine concentration in whole blood from 30 healthy male volunteers (aged 77 ± 12 years) was 178.5 ± 118.1 nmol/L. Overall, the method is easy to perform, allowing a rapid and accurate assessment of whole blood concentrations of hercynine.

LC–tandem mass spectrometry method for the simultaneous determination of metformin and sitagliptin in human plasma after ion-pair solid phase extraction

A reversed-phase liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) method was established for simultaneous determination of two oral hypoglycemic drugs metformin (MET) and sitagliptin (STG) in human plasma. The analytes were extracted from 50μL human plasma by ion-pair solid phase extraction using sodium lauryl sulphate on Phenomenex Strata-X (30mg/1mL) cartridges. The chromatographic separation was accomplished on XSelect HSS CN (150×4.6mm, 5μm) column using mobile phase consisting of methanol-8.0mM ammonium formate in water, pH 4.5 (80:20, v/v) under isocratic condition. Tandem MS detection was performed on a triple quadrupole spectrometer equipped with an electrospray ionization source, operated in the positive mode. Multiple reaction monitoring (MRM) was used to quantify the analytes following transitions, m/z 130.1→60.1 and m/z 408.3→235.1 for MET and STG respectively. The method displayed acceptable linearity in the concentration range of 4.00–3200ng/mL for MET and 1.00–800ng/mL for STG. The intra-batch and inter-batch precisions were ≤5.1% and accuracy ranged from 96.5 to 103.3% for both the drugs. The mean recovery of MET and STG obtained from spiked plasma samples was 82.5% and 90.4% respectively with minimal matrix interference. Both the drugs were found to be stable under all mandatory storage conditions. The validated method was successfully applied to a clinical pharmacokinetic study for a fixed-dose tablet formulation containing 500mg MET and 50mg STG in 16 healthy volunteers.