Simultaneous determination of Obeticholic acid and its two major metabolites in human plasma after administration of Obeticholic acid tablets using ultra-high performance liquid chromatography tandem mass spectrometry.

Obeticholic acid (OCA), a semisynthetic bile acid derivative, was approved for its therapeutic use in primary biliary cirrhosis. OCA has a enterohepatic circulation and host-gut microbiota metabolic interaction, which produce various metabolites. Such metabolites, especially structural isomers of OCA, together with the need to achieve idea lower limit of quantitation (LLOQ) with minimum matrix interference, bring about significant difficulties to the bioanalysis of OCA. Herein, by applying a combination of solid-phase extraction (SPE) and ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), we introduced an approach for the bioanalysis of OCA along with its two major metabolites-glyco-OCA (GOA) and tauro-OCA (TOA) in human plasma, the full validation results of which showed excellent performance. The quantitative range is 0.2506 âˆ¼ 100.2 ng/mL for OCA, 0.2500 âˆ¼ 100.0 ng/mL for GOA, as well as 0.1250 âˆ¼ 50.00 ng/mL for TOA, respectively. This method was successfully applied to the pharmacokinetic studies in healthy subjects following administration of OCA tablets.

Determination of azodicarbonamide in flour samples using high-performance liquid chromatography-tandem mass spectrometry with xanthydrol pre-column derivatisation.

Azodicarbonamide (ADA) is approved as a food additive in flour products due to its oxidising and bleaching properties. However, it is prohibited in Australia and Europe on account of its toxicity and the risk of causing asthma in humans. A method was developed to determine ADA in actual flour samples. This work presents an optimised methodology based on derivatisation and clean-up procedures followed by ultra-performance liquid chromatography coupled with electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS/MS). The analytical method was successfully validated. An excellent result was obtained for the linearity of matrix-matched calibration curves (R2 > 0.99) in the concentration range of 0.10-80 mg/kg. The recovery rate varied from 81.7% to 102.3%. The relative standard deviations (RSDs) of repeatability (n = 6) were 1.3-4.1%, and inter-day RSDs (n = 6) were 2.2-4.8%. The limit of detection and the limit of quantification were 0.014 and 0.042 mg/kg, which were significantly lower than the requirement of 45 mg/kg stipulated in the Chinese National Food Safety Standard (GB 2760-2014). The detection rate of ADA in 26 flour samples was 23.1%, with the concentration ranging from 0.023 to 23.2 mg/kg.

A UPLC-MS/MS coupled with GC-MS method for quantification of twenty-one chemical ingredients from Suxiao Jiuxin pill in multiple tissue of rat and its application to tissue distribution study.

Suxiao Jiuxin pill (SJP) was a commonly-used traditional Chinese medicine for treating cardiovascular diseases. It was composed of the rhizome of Ligusticum chuanxiong Hort. and Borneolum Syntheticum. The distribution of SJP in vivo was still ambiguous. A UPLC-MS/MS coupled with GC-MS method was developed to quantify twenty-one chemical ingredients in multiple tissues from rat after administration of SJP. Protein precipitation and liquid-liquid microextraction were both utilized in sample pretreatment. All analytes were detected under acceptable specificity, linearity (correlation coefficient > 0.992), sensitivity (LLOQ < 12.5 ng/mL), precision (RSD < 14.8 %), accuracy (RE < ±14.6 %), extraction recovery (between 52.8 % and 124.1 %), matrix effect (ranged from 60.5 % and 149.7 %) and stability (RE < ±16.0 %). The established method was successfully applied in the tissue distribution study of SJP in rats. As a result, the distribution characteristics of ten analytes were clearly elucidated, including borneol, isoborneol, ligustilide, senkyunolide A, ferulic acid, senkyunolide I, levistolide A, neocnidilide, senkyunolide H and angelicide. The information provided by this research was greatly meaningful for the active chemical ingredient exploration and clinical application of SJP.

Chemical Constituents from the Whole Plants of Limonium sinense and Their in vitro Anti-inflammatory Activity.

The Yellow River Delta possesses lots of characteristic medicinal plants due to its high salinity and high alkaline environment and Limonium sinense is an iconic plant. However, there are very few studies on L. sinense and its chemical constituents have not been investigated in recent ten years. In the present study, the chemical constituents and bioactivities of L. sinense were fully studied for the first time. UPLC-MS/MS method combined with database comparison identified 109 compounds mainly including flavonoids, alkaloids and polyphenols. In addition, the potential bioactivities of L. sinense were considerated as anti-inflammatory, anti-oxidative, anti-tumor, hepatoprotective and hpyerglycemic activities based on these identified compounds and their related literature. Furthermore, four derivatives of 12-oxo-phytodienoic acid and butenolide including two new ones (1 and 2) were isolated from the whole plants of L. sinense. Their structures, including the absolute configurations, were determined by the analysis of comprehensive spectroscopic data. All isolates were evaluated for their anti-inflammatory activity. Compound 1 exhibited moderate anti-inflammatory activity with IC50 value of 37.5 ± 1.2 µM on NO production level.

UPLC-MS/MS method for fluconazole determination in plasma and its application in Mexican patients with candidaemia.

Aim: An accurate and fast ultra-high performance liquid chromatography coupled with tandem mass spectrometry analytical method was developed and validated for quantifying fluconazole levels in human plasma according to the US FDA guidelines.Materials & methods: A simple protein precipitation by acetonitrile was employed for the sample preparation. The chromatographic separation was carried out using isocratic elution of water (0.1% formic acid) and acetonitrile on an Acquity ultra-high performance liquid chromatography HSS T3 column. Samples from ten adult patients diagnosed with candidemia who received fluconazole treatment were analyzed.Results & conclusion: The method demonstrated excellent linearity and stability within the 1-50 µg/ml range (r2 >0.999). The intraday and interday precision were determined with coefficient of variation values ranging from 1.4 to 4.38% and 2.8 to 6.6%, respectively. This rapid and selective method has successfully analyzed 27 plasma samples. The straightforward sample preparation in a single step and the reduced analysis time make this method suitable for adult patients with candidemia, leading to improved clinical outcomes.

[Box: see text].

Excretion characteristics of main compounds of Yigong San in urine, feces, and bile of rats.

Yigong San (YGS) is a traditional Chinese medicine formula used for pediatric anorexia, chronic atrophic gastritis, and irritable bowel syndrome. In this study, the excretion of eight main compounds, including liquiritin; isoliquiritin; hesperidin; ginsenosides Rb1, Re, and Rg1; and atractylenolides I and II, in rat urine, feces, and bile, was investigated by ultra-high performance liquid chromatography-tandem mass spectrometry. The results showed that the cumulative excretion rates of the compounds in rat urine, feces, and bile were 0.018-1.15%, 0.024-19.89%, and 0.0025-0.72%, respectively. Among the eight compounds detected, liquiritin was the richest in urine, and ginsenosides Re and Rg1 and atractylenolide I were mainly found in feces and bile. In summary, the main components of YGS are excreted via multiple approaches. Liquiritin is mainly through urine, whereas isoliquiritin; hesperidin; ginsenosides Rb1, Re, and Rg1; and atractylenolides I and II are mainly through feces. The excretion of these compounds in bile is usually positively correlated with that in feces. This study lays a foundation for further pharmacological research and application of YGS.

Squaraine-Linked Magnetic Covalent Organic Framework as a Solid-Phase Extraction Absorbent to Determine Trace Phenylpyrazoles.

Phenylpyrazoles are widely used pesticides in the food industry. It is highly desirable to develop efficient pre-treatment and analysis methods to extract and detect phenylpyrazoles in complex food matrices. Herein, the study reports novel squaraine-linked zwitterionic core-shell magnetic covalent organic frameworks (MCOFs),  which are found to be excellent pretreatment materials for the detection of trace phenylpyrazoles in samples. By coupling MCOFs to magnetic solid-phase extraction (MSPE) with Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS) analysis, the detection of phenylpyrazoles (fipronil, fipronil sulfone, fipronil sulfide, fipronil de-sulfoxide, fipronil desulfinyl, ethiprole, and flufiprole) is achieved and shows good linearity at concentrations of 1-800 µg L-1 (R2 ≥ 0.9930). The limit of detection (LOD), limit of quantification (LOQ), and recovery rates are 0.01-0.50 µg kg-1, 0.04-1.72 µg kg-1, and 70.96-115.32%, respectively. More importantly, this method is successfully applied to determine the phenylpyrazoles in commercial egg, poultry, milk, jujube, cabbage, tea, and rice with a detection rate of ≈0.04%. Therefore, the developed method may contribute to a new strategy for the purification and multi-target extraction of complex food matrices.

[Simultaneous determination of 61 hormones in water by solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry].

Concerns over the emergence of steroid hormones as pollutants in water have grown. Steroid hormone compounds present challenges in the simultaneous detection of total residual hormones owing to their analogous structures and diverse types. In this study, we established a rapid and high-throughput continuous online method based on solid phase extraction (SPE) coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the simultaneous determination of 61 hormone components, including 48 glucocorticoids, 1 mineralocorticoid, 4 androgens, and 8 progesterones, in water. Various SPE columns were investigated to assess their extraction efficiency for enriching and purifying target compounds in a large sample volume (1 L). An HC-C18 SPE column was selected because of its superior performance. Acetonitrile was used as a washing solution during SPE to ensure that the majority of the tested substances achieved recoveries exceeding 70% and effectively avoid interferences from water-soluble components. Various C8 and C18 columns were tested, and the optimal HPLC conditions for hormone retention were established. We systematically evaluated different UPLC columns and mobile phases, including methanol-water and acetonitrile-water systems with 0.1% formic acid added to the aqueous phase. The optimized UPLC conditions were as follows: BEH C18 column (100 mm×2.1 mm, 1.7 µm); column temperature, 40 ℃; flow rate, 0.3 mL/min; injection volume, 5 µL; mobile phase A: 0.1% formic acid aqueous phase; mobile phase B: acetonitrile. Gradient elution was performed as follows: 0-0.5 min, 30%B; 0.5-15.0 min, 30%B-75%B; 15.0-18.0 min, 75%B-98%B; 18.0-19.0 min, 98%B; 19.0-19.1 min, 98%B-30%B; 19.1-20.0 min, 30%B. Both positive- and negative-ion modes were explored in the UPLC-MS/MS experiment to obtain the full scan of the parent ions, and positive mode was finally selected for electrospray ionization (ESI). Two product ions exhibiting strong signals and minimal interference were selected for quantitative and qualitative ion analyses, using an external standard method for quantification. MS/MS was performed in positive-ion (ESI+) mode with multiple reaction monitoring (MRM) scanning. The MS/MS parameters were as follows: atomizing gas pressure, 379 kPa; curtain air pressure, 241 kPa; spray voltage, 5500 V; desolvation temperature, 550 ℃; collision exit voltage (CXP), 13 V; intake voltage (EP), 10 V; and residence time of each ion pair, 0.5 ms. Other instrument settings, such as the collision energy and declustering voltage, were also optimized. The 61 hormones exhibited excellent linear relationships within their corresponding concentration ranges, with correlation coefficients greater than 0.99. The method detection limits (MDLs) were in the range of 0.05-1.50 ng/L. The average recoveries of the 61 hormones across three spiked levels ranged from 62.3% to 125.2%, with relative standard deviations (RSDs, n=6) of 1.1%-10.5%. Using this method, we successfully detected 10 hormone components (cortisone, fluticasone propionate, ciclesonide, betamethasone dipropionate, clobetasone butyrate, diflucortolone valerate, halobetasol propionate, isoflupredone, difluprednate, and hydroxyprogesterone caproate) in various surface water and groundwater samples collected from the Taihu Basin region. The SPE-UPLC-MS/MS method presented in this paper is simple, highly sensitivity, and exceptionally accurate. Thus, it exhibits promising potential for tracing targeted hormone residues in water and will be of great value in monitoring and ensuring water safety. Finally, a regional analysis was conducted on the hormone levels in water, and suggestions were made for the targeted treatment of hormone residues in future sewage treatment processes.

Determination of doxorubicin in plasma and tissues of mice by UPLC-MS/MS and its application to pharmacokinetic study.

A rapid and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous determination of doxorubicin (DOX) in mouse plasma and tissues, including the heart, liver, spleen, lung, kidney and tumor, and to investigate the pharmacokinetics and distribution in mice. In this study, daunorubicin (DNR) was used as an internal standard, and the mobile phase consisted of ammonium formate 2 mM containing 0.1 % formic acid (A) and acetonitrile (B), the chromatographic column was ACQUITY UPLC BEHTM C18 with a gradient elution at a flow rate of 0.2 mL/min. Electrospray ionization (ESI) in positive ion pattern was utilized for the ion separation of DOX, with the ions used for quantitative analysis being DOX m/z 544.28 â†’ 397.10 and DNR m/z 528.35 â†’ 321.08, respectively. The results showed that a good linear relationship in the calibration curve range of 1-800 ng/mL in mouse plasma and 1-2500 ng/g in tissues (R2 > 0.99) with the limits of quantification of 1 ng/mL in plasma and tissues. The method exhibited good matrix effect and extraction recovery, with the intra-day and inter-day precision of plasma and tissue were less than 10.3 % and 15.4 %, and the relative error (RE) were both less than ±14.8 % and ±18.9 %, respectively. The stability results under different conditions were found to be accurate. It also revealed the distribution of DOX in various tissues of mice, with the concentration ranking as liver > heart > kidney > spleen > lung > tumor. This method was successfully used to the study for the pharmacokinetics in plasma and drug distribution in tissues of BALB/c mice.

Characterization of the in vitro metabolic profile of nazartinib in HLMs using UPLC-MS/MS method: In silico metabolic lability and DEREK structural alerts screening using StarDrop software.

The orally given, irreversible, third-generation inhibitor of the epidermal growth factor receptor (EGFR), known as Nazartinib (EGF816), is now undergoing investigation in Phase II clinical trials conducted by Novartis for Non-Small Cell Lung Cancer. The primary aim of the current research was to establish a rapid, specific, environmentally friendly, and highly versatile UPLC-MS/MS methodology for the determination of nazartinib (NZT) levels in human liver microsomes (HLMs). Subsequently, same approach was used to examine the metabolic stability of NZT. The UPLC-MS/MS method employed in HLMs was validated as stated in the bioanalytical method validation criteria outlined by the US- FDA. The evaluation of the metabolic stability of NZT and the identification of potentially structural alarms were performed using the StarDrop software package that includes the P450 and DEREK software. The calibration curve for NZT showed a linearity in the range from 1 to 3000 ng/mL. The inter-day accuracy and precision exhibited a range of values between -4.33 % and 4.43 %, whereas the intra-day accuracy and precision shown a range of values between -2.78 % and 7.10 %. The sensitivity of the developed approach was verified through the determination of a LLOQ of 0.39 ng/mL. The intrinsic clearance and in vitro half-life of NZT were assessed to be 46.48 mL/min/kg and 17.44 min, respectively. In our preceding inquiry, we have effectively discerned the bioactivation center, denoted by the carbon atom between the unsaturated conjugated system and aliphatic linear tertiary amine. In the context of computational software, making minor adjustments or substituting the dimethylamino-butenoyl moiety throughout the drug design process may increase the metabolic stability and safety properties of new synthesized derivatives. The efficiency of utilizing different in silico software approaches to conserve resources and reduce effort was proved by the outcomes attained from in vitro incubation experiments and the use of NZT in silico software.

An LC-MS/MS method for the determination of Lifitegrast in human plasma and tear and its application in the pharmacokinetic study.

Aim: A new, selective and simple UPLC-MS/MS method was developed and validated for the determination of lifitegrast in human plasma and tear in order to obtain PK data. Materials & methods: Lifitegrast-d4 solutions were added in the samples, and then were extracted and transferred to a UPLC vial. Results: The respective working ranges were 25.00-2000.00 pg/ml in plasma and 4.00-1000.00 µg/ml in tear. The fully validated method complied with existing regulatory criteria for accuracy and precision, recovery, etc. It was applied to plasma and tear samples, which were from a clinical study, successfully. Conclusion: This method is useful in the evaluation of lifitegrast in plasma and tear.

[Box: see text].

Chemical profiling and quality evaluation of raw and vinegar-processing frankincense by multiple UPLC-MS/MS techniques.

INTRODUCTION: Frankincense is used for analgesic, tumor-suppressive, and anti-inflammatory treatments in Traditional Chinese Medicine but poses toxicological concerns. Vinegar processing is a common technique used to reduce the toxicity of frankincense. OBJECTIVE: This study aimed to investigate the chemical composition and quality evaluation of raw and vinegar-processing frankincense by multiple UPLC-MS/MS techniques. Additionally, we purposed refining the vinegar processing technique and identifying potentially harmful ingredients in the raw frankincense. METHODOLOGY: Sub-chronic oral toxicity studies were conducted on raw and vinegar-processing frankincense in rats. The composition of frankincense was identified by UPLC-Q-TOF-MS/MS. Chemometrics were used to differentiate between raw and vinegar-processing frankincense. Potential chemical markers were identified by selecting differential components, which were further exactly determined by UPLC-QQQ-MS/MS. Moreover, the viability of the HepG2 cells of those components with reduced contents after vinegar processing was assessed. RESULTS: The toxicity of raw frankincense is attenuated by vinegar processing, among which vinegar-processing frankincense (R40) (herb weight: rice vinegar weight = 40:1) exhibited the lowest toxicity. A total of 83 components were identified from frankincense, including 40 triterpenoids, 37 diterpenoids, and 6 other types. The contents of six components decreased after vinegar-processing, with the lowest levels in R40. Three components, specifically 3α-acetoxy-11-keto-ß-boswellic acid (AKBA), 3α-acetoxy-α-boswellic acid (α-ABA), and 3α-acetoxy-ß-boswellic acid (ß-ABA), inhibited the viability of HepG2 cells. The processing of frankincense with vinegar at a ratio of 40:1 could be an effective method of reducing the toxicity in raw frankincense. CONCLUSION: Our research improves understanding of the toxic substance basis and facilitates future assessments of frankincense quality.

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

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

Biosensor-based active ingredient recognition system for screening potential small molecular Severe acute respiratory syndrome coronavirus 2 entry blockers targeting the spike protein from Rugosa rose.

The traditional formulation Hanchuan zupa granules (HCZPs) have been widely used for controlling coronavirus disease 2019 (COVID-19). However, its active components remain unknown. Here, HCZP components targeting the spike receptor-binding domain (S-RBD) of SARS-CoV-2 were investigated using a surface plasmon resonance (SPR) biosensor-based active ingredient recognition system (SPR-AIRS). Recombinant S-RBD proteins were immobilized on the SPR chip by amine coupling for the prescreening of nine HCZP medicinal herbs. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) identified gallic acid (GA) and methyl gallate (MG) from Rosa rugosa as S-RBD ligands, with KD values of 2.69 and 0.95 µM, respectively, as shown by SPR. Molecular dynamics indicated that GA formed hydrogen bonds with G496, N501, and Y505 of S-RBD, and MG with G496 and Y505, inhibiting S-RBD binding to angiotensin-converting enzyme 2 (ACE2). SPR-based competition analysis verified that both compounds blocked S-RBD and ACE2 binding, and SPR demonstrated that GA and MG bound to ACE2 (KD = 5.10 and 4.05 µM, respectively), suggesting that they blocked the receptor and neutralized SARS-CoV-2. Infection with SARS-CoV-2 pseudovirus showed that GA and MG suppressed viral entry into 293T-ACE2 cells. These S-RBD inhibitors have potential for drug design, while the findings provide a reference on HCZP composition and its use for treating COVID-19.

An innovative UPLC-MS/MS method for the quantitation and pharmacokinetics of eupafolin in rat plasma.

In this experiment, a rapid and highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technology was established and validated for the quantitation and pharmacokinetic analysis of eupafolin in rat plasma, utilizing licochalcone B as internal standard (IS). After liquid-liquid extraction of the analyte samples by ethyl acetate, chromatographic separation was achieved using a UPLC HSS T3 column under gradient elution conditions, with the mobile phase consisting of acetonitrile and water (with 0.1 % formic acid). Eupafolin was quantified by multiple reaction monitoring (MRM) in electrospray positive-ion mode (ESI+), employing the mass transition m/z 315.2 â†’ 300.3 for eupafolin and m/z 285.4 â†’ 270.3 for IS. Eupafolin demonstrated excellent linear relationship (r > 0.99) over the concentration range of 1.25-1250 ng/mL, with the lower limit of quantification (LLOQ) of the UPLC-MS/MS assay determined as 1.25 ng/mL. Method validation followed the bioanalytical method validation criteria outlined by the FDA. The accuracy of eupafolin ranged from 86.7 % to 111.2 %, and the precision was less than 12 %. The matrix effect was observed at 92.8 %-98.6 %, while the recoveries exceeded 83.2 %. The established UPLC-MS/MS assay was successfully employed for the pharmacokinetic evaluation of eupafolin in rats. The half-lives (t1/2z) were determined to be 1.4 ± 0.4 h and 2.5 ± 1.4 h for intravenous and oral administration, respectively. Notably, the bioavailability of eupafolin was relatively low (8.3 %). The optimized UPLC-MS/MS technology showed highly sensitive, selective, and effective, rendering it suitable for the pharmacokinetics of eupafolin in preclinical practice.

Validated UPLC-MS/MS method for quantification of melatonin receptor agonists and dual orexin receptor antagonists in human plasma and breast milk: Application to quantify suvorexant and lemborexant in clinical samples.

Pharmaceutical care is important for mental health during the perinatal period, which is often characterized by insomnia. In recent years, prescriptions of melatonin receptor agonists (MRAs) and dual orexin receptor antagonists (DORAs) for insomnia have increased; however, their use during the perinatal period has scarcely been reported. In the present study, we developed a UPLC-MS/MS method for the quantification of ramelteon, its metabolite M-II, suvorexant, and lemborexant in human plasma and breast milk to accumulate information on the safety and transfer of MRAs and DORAs into breast milk. Samples of MRAs (ramelteon and M-II) in plasma and breast milk were prepared using liquid-liquid extraction (LLE) with ethyl acetate. For DORAs (suvorexant and lemborexant), LLE with ethyl acetate was applied to plasma samples. For breast milk samples, significant ion suppression was observed for LLE with ethyl acetate. Solid-phase extraction (SPE) cartridges capable of removing phospholipids improved the matrix effects. Finally, protein precipitation with methanol and an SPE cartridge, InertSep® Phospholipid Remover, were selected for breast milk sample preparation. An ACQUITY UPLC BEH C18 column was used for analyte separation. MRAs and DORAs were eluted using isocratic and gradient elution, respectively, and analyzed using electrospray ionization in the positive mode with multiple reaction monitoring. The range of calibration curve for MRAs and DORAs was 0.1-25 and 0.5-50 ng/ml, respectively. Both the plasma and breast milk samples exhibited good linearity over this range. The method was validated by evaluating its accuracy and precision, matrix effect, recovery, carry-over, stability, and dilution integrity. The validated method was successfully applied to clinical samples donated by breastfeeding women and the milk/plasma (M/P) ratio and relative infant dose (RID) of lemborexant (one case) and suvorexant (two cases) were estimated. The M/P ratio of lemborexant was <1, and the RID was 1.05 %. The M/P ratio of suvorexant was <0.1, and RID was 0.11-0.20 %. This method will be useful for future studies evaluating the safety of these drugs during breastfeeding.

Simultaneous determination of icotinib, osimertinib, aumolertinib, and anlotinib in human plasma for therapeutic drug monitoring by UPLC-MS/MS.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) such as icotinib, osimertinib, and aumolertinib have emerged as promising treatment options for EGFR mutated Non-small cell lung cancer (NSCLC) patients. Additionally, anlotinib, an anti-angiogenic agent targeting VEGFR, FGFR, and PDGFR, has been used in combination with EGFR-TKIs in NSCLC cases. A method utilizing ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated for quantifying icotinib, osimertinib, aumolertinib and anlotinib simultaneously in clinical TDM. The chromatographic separation was performed using a Kinetex C18 column (100 mm × 2.1 mm) and an elution gradient of ammonium acetate in water acidified with 0.1 % formic acid and in acetonitrile. The assay was validated over a linear range of 4-2000 ng/mL for icotinib, 2-1000 ng/mL for osimertinib, 1-500 ng/mL for aumolertinib, and 0.8-400 ng/mL for anlotinib, following the guidelines on bioanalytical methods by FDA. The quantification method exhibited satisfactory performance in terms of selectivity, accuracy (from 91.3 % to 107 %), precision (intra- and inter-day coeffficients of variation ranged from 0.944 % to 7.48 %), linearity, recovery (from 86.0 % to 91.9 %), matrix effect (IS-normalized matrix factors were from 96.7 % to 102 %), and stability. Overall, the method proved to be sensitive, reliable, and straightforward, enabling successful simultaneous determination of blood concentrations of icotinib, osimertinib, aumolertinib, and anlotinib in patients. The validity of the method has been confirmed across various instruments.

Simultaneous determination of quaternary phosphonium compounds and phosphine oxides in environmental water and solid samples by ultrahigh performance liquid chromatography-tandem mass spectrometry.

Quaternary phosphonium compounds (QPCs) and phosphine oxides (POs) are emerging contaminants that are attracting increasing attention. In the present study, a method for the quantification of QPCs and POs in multiple environmental media was developed using ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Analytes were extracted from water samples using solid phase extraction, and for the solid samples, ultrasonic extraction was employed. Compared with analytical methods established by previous studies, the approach developed in this study is more suitable for the quantitative analysis of compounds along with high sensitivity. The method quantification limit reached 0.12-2.55 ng⋅L-1 in water samples and 0.004-0.10 ng⋅g-1 in solid samples. The recoveries of target analytes spiked at low, medium and high concentrations in water and solid samples were in the range of 56.4-120 %, with relative standard deviations below 20 % (n = 6). Furthermore, the validated method succeeded in applying to analyse of eight QPCs and four POs in real environmental samples. At least five QPCs and two POs were detected in each environmental medium. This quantitative method would assist in further investigations on the occurrence, migration and the source of QPCs and POs.

A Quick and Sensitive LC-MS/MS Method for Simultaneous Quantification of Sofosbuvir Metabolite (GS-331007) in Human Plasma: Application to Hepatitis C Infected Patients with End-Stage Renal Disease.

Background: Sofosbuvir (SOF) is a revolutionary treatment for patients with hepatitis C virus (HCV). However, its efficacy and safety among patients with end-stage renal disease (ESRD) remains controversial. In this study, we examined the levels of SOF metabolite (GS-331007) (SOF-007) in human plasma of patients infected with HCV having ESRD using an optimized liquid chromatography-mass spectrometry (LC-MS) analytical method. Methods: In this case-control study, 10 clinically confirmed cases and five controls were enrolled. SOF-007 was extracted from plasma using methanol precipitation. The limit of detection (LOD) for the drug and its metabolite were 0.85 and 2.3, respectively. Such a wide range of quantification in a period of separation time shorter than 3.0 minutes (run time) allowed monitoring of the plasma concentration of analytes up to 4 hours (pre-dialysis and post-dialysis) for 12 weeks in non-cirrhotic patients with HCV infection undergoing dialysis. Results: SOF-007 in the plasma of HCV patients with healthy kidneys showed no cumulative effect. An analysis comparing patients with ESRD and healthy participants showed that their behaviour was similar, followed by dialysis with a relatively small cumulative effect. Conclusion: The plasma concentrations of SOF-007 decreased significantly after the 4-hour period of dialysis compared with the plasma concentrations hemodialysis of pre-dialysis in HCV patients with ESRD.

Development of a UPLC-MS/MS method for quantifying KPT-335 (Verdinexor) in feline plasma for a study of PK.

KPT-335 (Verdinexor) is a novel SINE that potently inhibits the nucleoprotein Exportin 1 (XPO1/CRM1) of tumor cell lines and reduces the replication level of the influenza virus. KPT-335 is mainly used for the treatment of canine tumors. Drugs for the effective treatment of feline tumors are currently unavailable in China. KPT-335 may have potential in the treatment of cat tumors. However, the effects of KPT-335 in cats are unreported, and no relevant methodology has been established for pharmacokinetic studies. In this study, a UPLC-MS/MS method was developed to determine KPT-335 concentrations in cat plasma, followed by pharmacokinetic studies. Briefly, plasma proteins are precipitated with acetonitrile, and the supernatant was collected for detection after centrifugation. The linearity for KPT-335 in cat plasma was in the range of 5-1,000 ng/mL. Satisfactory accuracy and precision were obtained. The intra-day accuracy was between -4.10% and 10.48%, the precision was ≤4.65%; the inter-day accuracy was between -0.11% and 8.09%, and the precision was ≤5.85%. Intra-day and inter-day accuracy and precision were within regulatory limits. The results of preliminary pharmacokinetic studies were as follows: Tmax was 1.46 ± 0.51 h; Cmax was 239.54 ± 190.60 ng·mL-1; T1/2 was 5.16 ± 2.30 h; AUC0-t was 1439.85 ± 964.64 ng·mL-1·h. The AUC0-∞ was 1589.82 ± 1003.75 ng·mL-1·h. The purpose of this study was to develop a rapid and simple UPLC-MS/MS method to detect KPT-335 concentration in cat plasma and to conduct preliminary pharmacokinetic studies to support the future application of KPT-335 in felines.