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Accurate measurement of serum glycocholic acid (GCA) is crucial for evaluating the activity of chronic hepatitis. Moreover, GCA is a novel identified biomarker for hepatocellular carcinoma. Although some laboratories have used the liquid chromatography-tandem mass spectrometry (LC–MS/MS) method to measure GCA in recent years, the problem of potential interference of GCA analogues has not been solved well yet. Neither reference measurement procedures nor reference materials for GCA have been listed in the Joint Committee for Traceability in Laboratory Medicine (JCTLM) database. For standardization of GCA, it is urgent to establish a candidate measurement procedure for GCA. In this study, a candidate reference measurement procedure for the quantification of GCA in human serum based on isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC–MS/MS) by a two-step sample pretreatment of protein precipitation and MAX solid-phase extraction was developed and validated. GCA can be completely separated from its structural analogues with gradient elution in 9 min compared with short time gradients published in previous literature by Huang's group. Method validation indicated perfect quantitation precision with intra-day and inter-day values that were ≤1.30% and ≤1.80%, respectively. The method showed excellent linearity with high regression coefficients (R2 > 0.999) over a range of 0.92 ng/g–38.38 μg/g and perfect recoveries at three spiked levels (99.87–100.43%). No interference, matrix effect, and carryover were observed. Moreover, the cRMP was successfully applied to measure GCA in serum samples and compared with two immunoassays in a clinical laboratory. As a candidate reference method, this method can promote a GCA standardization program. [ABSTRACT FROM AUTHOR]

A candidate reference measurement procedure (RMP) for serum theophylline via isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. With a single-step precipitation pretreatment and a 6-min gradient elution, the method achieved baseline separation of theophylline and its analogs on a C18-packed column. A bracketing calibration method was used to ensure repeatable signal intensity and high measurement precision. The intra-assay and inter-assay imprecisions were 1.06%, 0.84%, 0.72% and 0.47%, 0.41%, 0.25% at concentrations of 4.22 µg/mL (23.40 µmol/L), 8.45 µg/mL (46.90 µmol/L), and 15.21 µg/mL (84.43 µmol/L), respectively. Recoveries ranged from 99.35 to 102.34%. The limit of detection (LoD) was 2 ng/mL, and the lowest limit of quantification (LLoQ) was 5 ng/mL. The linearity range extended from 0.47 to 60 µg/mL (2.61–333.04 µmol/L). No ion suppression and carry-over (< 0.68%) were observed. The relative bias for this candidate RMP that participated in 2023 External Quality Control for Reference Laboratories (RELA) conducted by the International Federation of Clinical Chemistry (IFCC) was within a range of 0.17 to 0.93%. Furthermore, two clinical immunoassay systems were compared with this candidate RMP, demonstrating good correlations. The results of the Trueness Verification Plan indicate significant differences among routine systems, highlighting the need for standardization efforts. The developed candidate RMP for serum theophylline serves as a precise reference baseline for standardizing clinical systems and assigning values to reference materials. [ABSTRACT FROM AUTHOR]

A variety of LSD analogs have emerged in recent years with dual purposes of avoiding prosecution from possession while providing new options for those willing to experiment with hallucinogenic drugs. In this study, a previously published automated sample preparation method for LSD and its primary metabolite (OH‐LSD) was utilized to extract LSD, OH‐LSD, and nine LSD analogs from urine. The liquid chromatography tandem mass spectrometry (LC–MS/MS) method was modified from the previously published LC conditions to utilize a different analytical column and gradient elution program. Mobile phases of 10 mM ammonium formate with 0.1% formic acid in deionized water (mobile phase A) and 0.1% formic acid in methanol (mobile phase B) were employed. The method was validated to ANSI/ASB Standard 036 with a 0.1 ng/mL limit of detection for all analytes and was utilized for the analysis of 325 urine specimens. Although no LSD analogs were observed in the samples analyzed, this validated method was demonstrated to be suitable for the analysis of these compounds in laboratories seeking to expand their testing scope. Automated sample preparation allows for the efficient analysis of these analytically challenging compounds with minimal manual handling. Additionally, there was no increased analytical time burden when the LC column and gradient were modified to target nine additional analytes. Detection may improve as new reference standards are developed to allow laboratories to focus on the metabolic products of these analogs. For now, this validated procedure can assist with the routine analysis and surveillance of these emerging substances. [ABSTRACT FROM AUTHOR]

The most common strategy to assess the occupational exposure risk to hazardous drugs in cancer healthcare settings is by monitoring environmental contamination of work surfaces with cytotoxic drugs. Healthcare workers, especially pharmacy technicians and nursing, handle multiple hazardous drugs, so they really may be exposed to different cytotoxic drugs simultaneously. Therefore, simultaneous determination of several cytotoxic drugs provides a more accurate assessment of the real occupational exposure risk in healthcare settings. Our objective was to develop a method for surface wipe sampling and a quantification method for five cytotoxic drugs commonly used in chemotherapy treatments preparation: cyclophosphamide, 5-fluorouracil, epirubicin, gemcitabine and paclitaxel. Wiping procedure was performed using cellulose swabs moistened in a mixture solution containing acetonitrile, water, 2-propanol and methanol with 0.1% formic acid. The obtained extracts were simultaneously quantified by an LC-MS/MS method. Chromatographic separation was achieved using an Acquity UPLC® BEH C18 column by a gradient elution, and detection was carried out in multiple reaction monitoring mode with electrospray source operating in positive and negative ion mode. Wipe and extraction procedures developed were simple and easy to implement, being able to recover the cytotoxic target drugs from two type surfaces sampling, stainless steel surfaces and polyethylene bags surfaces. The analytical method was linear over the calibration range and the limits of quantification were 1 ng/mL for cyclophosphamide, gemcitabine and paclitaxel, 1.5 ng/mL for epirubicin and 5 ng/mL for 5-fluorouracil. Intra- and inter-day precision and accuracy for all drugs were always inferior to 15%. This work provides a suitable procedure to identify cytotoxic contamination on work surfaces, being a useful tool to monitor occupational exposure risk to hazardous drugs, as well as to evaluate the effectiveness of decontamination protocols applied and hazardous drug handling protocols in cancer healthcare settings. [ABSTRACT FROM AUTHOR]

We measured the intracellular concentrations of tenofovir-diphosphate (TFV-DP) and emtricitabine-triphosphate (FTC-TP) in dried blood spots (DBS) for pre-exposure prophylaxis (PrEP) adherence using sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS). A total of 191 DBS were obtained from 85 participants who were receiving tenofovir disoproxil fumarate (TDF; 300 mg) and emtricitabine (FTC; 200 mg) as PrEP at the Sexual Health Clinic, National Center for Global Health and Medicine, Tokyo, Japan. DBS punch (3 mm) added to 25 μL of 50% methanol and 400 μL of internal standard solution was used for solid phase extraction. Chromatographic separation was achieved on an Atlantis Premier BEH C18 AX Column (50 mm × 2.1 mm i.d.; particle size 1.7 μm) using gradient elution (flow rate: 0.6 mL/min); injection volume: 7 μL and run time: 5.5 min. Calibration curves for the two drugs were linear in the range 0.05–12.5 ng/punch. We determined the intracellular TFV-DP and FTC-TP concentrations in 191 DBS obtained from 85 patients administered with TDF and FTC as PrEP. The analytical performance data (calibration curve and QC samples) for all the analytical runs met the acceptance criteria. Intracellular concentrations of TFV-DP and FTC-TP in the DBS remained stable for at least 24 h after oral administration. A multiplex LC–MS/MS method was successfully developed for DBS, which can be useful for monitoring the levels of TFV-DP and FTC-TP in individuals receiving PrEP. [ABSTRACT FROM AUTHOR]

In this work, a UPLC-MS/MS assay was established for the determination of morphine, codeine, thebaine, papaverine and noscapine in rat plasma. ACQUITY UPLC BEH C18 column was employed for chromatographic separation with the mobile phase comprised acetonitrile-10 mmol L−1 ammonium acetate aqueous solution (0.05% aqueous ammonia) using gradient elution. Midazolam was used as internal standard (IS). Electrospray ionization (ESI) in positive-ion mode with reaction monitoring (MRM) was used for quantitative analysis. The calibration curves for morphine, codeine, thebaine, papaverine and noscapine demonstrated good linearity (r > 0.995) in the range of 5–500 ng mL−1 for morphine and codeine, and 1–100 ng mL−1 for thebaine, papaverine and noscapine. The intra-day and inter-day precisions of morphine, codeine, thebaine, papaverine and noscapine were within 15%, the intra-day and inter-day accuracies were 89–114%, the recovery was better than 65%, and the matrix effects were 96–112%. The developed UPLC-MS/MS assay was successfully applied in the pharmacokinetics of papaverine and noscapine. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rationale: Cloxacillin and flucloxacillin are prone to degradation and polymerization in humid and hot environments, and their polymers have long been recognized to trigger allergic manifestations. A series of the degradation and polymerized impurities in cloxacillin and flucloxacillin were separated and characterized to ensure safe use of these drugs by the public. Methods: By studying the chromatographic behavior of the degradation impurities and polymerized impurities in reversed‐phase high‐performance liquid chromatography (RP‐HPLC) gradient elution, the impurities in cloxacillin and flucloxacillin were effectively separated and eluted. RP‐HPLC tandem ion trap/time‐of‐flight mass spectrometry (MS) was applied to characterize the structures of unknown impurities eluted from the RP‐HPLC methods for cloxacillin and flucloxacillin. The mechanisms of formation of the impurities in cloxacillin and flucloxacillin were also investigated. Results: The structures of 10 unknown impurities in cloxacillin and 8 unknown impurities in flucloxacillin were elucidated based on the high‐resolution MSn data at positive and negative modes, respectively. Six polymerized impurities were found and characterized, of which three were from the polymerization of cloxacillin and three were from the polymerization of flucloxacillin. Conclusions: The study on the impurity profiles of cloxacillin and flucloxacillin provided a scientific basis for improving their production processes and quality control. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The oil used to fry food is often used multiple times to reduce costs. However, when foods containing sweeteners are processed in this way, the sweeteners may produce substances harmful to the body as a result of repeated frying at high temperatures. This article investigated the stability of sodium cyclamate during deep-frying by HPLC using a pre-column derivatization method. The results showed that cyclohexylamine was a decomposition product of a standard sample of sodium cyclamate when deep-fried at 200°C for 25 min. A pre-column derivatization/HPLC method was established to determine cyclohexylamine, a decomposition product of sodium cyclamate, under these conditions. Dansyl chloride was used as the derivatization reagent, the derivatization temperature was 60°C, the derivatization time was 20 min, the pH of sodium bicarbonate buffer solution was 11, and the concentration of dansyl chloride was 2.0 mg/mL. Detection was carried out by using an Agilent 1260 high-performance liquid chromatograph coupled with an ultraviolet detector. The ultraviolet detection wavelength was 254 nm, and the mobile phase was acetonitrile-1.0 g/L potassium dihydrogen phosphate solution at a flow rate of 1.0 mL/min. Gradient elution was adopted, the peak of the cyclohexylamine derivative appeared at a retention time of 17.75 min, and the peak area response value was the largest. The methodological validation analysis showed that the detection limit of cyclohexylamine was 0.5 mg/kg, the quantification limit was 2.0 mg/kg, and the spiked recoveries were in the range of 99.37–110.16%. The relative standard deviations (RSDs) were in the range of 0.17–1.26%. Four samples were tested and analyzed by the established method, and cyclohexylamine was not detected. [ABSTRACT FROM AUTHOR]

Objective Individual differences challenge the treatment of vancomycin, linezolid and voriconazole in severe infections. This study aimed to build a simple and economical method for simultaneous determination of the three antibiotics in human plasma by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS) and provided a reference for therapeutic drug monitoring (TDM) of infected patients. Methods The plasma samples were precipitated by acetonitrile and detected and separated on a shim-pack GIST C18 column following the gradient elution within 5 min. Mass quantification was performed on multiple reaction monitoring mode under positive electrospray ionization. Results The linear ranges of vancomycin, linezolid and voriconazole were 1.00–100.00, 0.10–15.00 and 0.10–20.00 μg·mL−1, respectively, with good linearity (R 2 > 0.99). The accuracy and precision, matrix effect, extraction recovery and stability were validated, and the results all meet the acceptance criteria of China Food and Drug Administration (CFDA) guidelines. Conclusion The UHPLC–MS/MS method was established and validated for the simultaneous determination of vancomycin, linezolid and voriconazole in human plasma and successfully applied to routine TDM for individualized treatment. [ABSTRACT FROM AUTHOR]

Copyright of Forensic Science & Technology is the property of Institute of Forensic Science, Ministry of Public Security and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

AbstractThe combination of an anticoagulant and a hypolipidemic agent is commonly used in patients at risk for stroke because it controls thrombosis and lowers cholesterol levels. However, the use of anticoagulants carries a high risk of life-threatening bleeding. To address the need for personalized clinical monitoring and risk management, we developed a rapid and sensitive HPLC method with a streamlined sample preparation process. This method enables the simultaneous determination of concentrations for two commonly used anticoagulant drugs (apixaban and rivaroxaban) and three hypolipidemic drugs (rosuvastatin, atorvastatin calcium, and simvastatin). The chromatographic conditions and sample preparation methods were optimized. The drugs were well separated by the gradient elution of phosphoric acid (0.01%, v/v) and acetonitrile at a flow rate of 1.0 mL/min within 40 min on an Athena C18-WP column (4.6 × 150 mm, 5-μm particle size). The proposed method was linear (r2 ≥ 0.994) within the concentration ranges of 0.22–20 μg·mL−1 for the five analytes, including the expected range of therapeutic concentrations. This method enables simultaneous monitoring of the levels of the mentioned drugs in clinical practice. Furthermore, the chromatographic conditions were simple and feasible, making them highly suitable for emergency clinical medication monitoring in basic medical institutions. [ABSTRACT FROM AUTHOR]

Cannabigerol, cannabidiol, cannabinol and cannabichromene are non-psychoactive phytocannabinoids, highly present in Cannabis sativa, for which numerous therapeutical applications have been described. However, additional pre-clinical and clinical data, including toxicopharmacokinetic and pharmacodynamic studies, remain required to support their use in clinical practice and new therapeutic applications. To support these studies, a new high performance liquid chromatography technique (HPLC) with diode-array detection (DAD) was developed and validated to quantify these cannabinoids in human plasma and mouse matrices. Sample extraction was accomplished by protein precipitation and double liquid–liquid extraction. Simvastatin and perampanel were used as internal standards in human and mouse matrices, respectively. Chromatographic separation was achieved in 16 min on an InfinityLab Poroshell® 120 C18 column (4.6 mm × 100 mm, 2.7 μm) at 40 °C. A mobile phase composed of water/acetonitrile was pumped with a gradient elution program at 1.0 mL min−1. The technique revealed linearity in the defined concentration ranges with a determination coefficient of over 0.99. Intra and inter-day accuracy and precision values ranged from −14.83 to 13.97% and 1.08 to 13.74%, respectively. Sample stability was assessed to ensure that handling and storage conditions did not compromise analyte concentrations in different matrices. Carry-over was absent and recoveries were over 77.31%. This technique was successfully applied for the therapeutic monitoring of cannabidiol and preliminary pre-clinical studies with cannabigerol and cannabidiol. All samples were within calibration ranges, with the exception of cannabigerol after intraperitoneal administration. This is the first HPLC-DAD technique that simultaneously quantifies cannabinoids in these biological matrices, supporting future pre-clinical and clinical investigations. [ABSTRACT FROM AUTHOR]

Ensuring the quality control of active pharmaceutical ingredients is crucial for drug products being introduced into the market. Even for established drugs, it is necessary to maintain a cutting-edge impurity control system. To analyze caffeine and chlorphenoxamine hydrochloride in their binary mixture, as well as theophylline and chlorphenoxamine N-oxide as related substances, a reversed phase-high performance liquid chromatography combined with a diode array detector system was created. The chromatographic separation was conducted using a C18 X-select Waters® column. The mobile phase consisted of 20.0 mM potassium dihydrogen phosphate modified to pH 3 with o-phosphoric acid and methanol. A gradient elution program was adopted at a flow rate of 1.3 mL/min and detected at a wavelength of 222 nm. The present methodology demonstrates a concentration ranging from 2–60, 1–80, 0.5–20 to 0.4–20 µg/mL for chlorphenoxamine hydrochloride, caffeine, chlorphenoxamine N-Oxide and theophylline, respectively. Chlorphenoxamine N-Oxide, being an impurity of chlorphenoxamine was prepared by refluxing intact drug with 5% H2O2 for 24 h at 100 °C. One of the objectives of the analytical community is to promote the adoption of green analysis methods, which involve the development of environmentally friendly techniques. The levels of greenness and whiteness were evaluated using four specific tools: Eco-Scale System, GAPI, AGREE, and RGB tool. Furthermore, we have evaluated the greenness of the analytical method presented and compared its performance and greenness to that of the approach described in the literature. In this study, results from CPX and CAF analysis were compared to those obtained in a previous study. The result shows that there is no notable variation in precision and accuracy. The proposed method was validated in accordance with the requirements of ICH. [ABSTRACT FROM AUTHOR]

AbstractIsosorbide dinitrate and hydralazine hydrochloride tablets treat heart failure in addition to conventional therapy, prolong hospitalization for heart failure, and enhance patient-reported functional status. LC-MS/MS methods developed and validated separately for the quantification of hydrazine mono-lactose adduct and hydrazine di-lactose adduct impurities in the isosorbide and hydralazine hydrochloride tablets. Separation of hydrazine mono-lactose adduct impurity achieved on ZIC-HILIC (100 × 4.6 mm, 5 µm) column with 0.1% formic acid in water as mobile phase A and acetonitrile as mobile phase B. The HPLC method gradient elution is; Tmin/% of B: 0/90, 15/40, 15.1/90, and 20/90. The flow rate is 1.0 mL per minute, and the injection volume is 20 µL. Separation of hydrazine di-lactose adduct impurity achieved on Inertsil HILIC (150 × 4.6 mm, 5 µm) column with 10 Mm ammonium acetate in water as mobile phase A and acetonitrile as mobile phase B. The HPLC method gradient elution is; Tmin/% of B: 0/90, 15/40, 15.1/90, and 18/90. The flow rate is 1.0 mL per minute, and the injection volume is 40 µL. Method validation has demonstrated both methods are specific, sensitive, linear, precise, accurate, stable and robust. [ABSTRACT FROM AUTHOR]

Mitapivat is a novel, first‐in‐class orally active pyruvate kinase activator approved by the US Food and Drug Administration in 2022 for the treatment of hemolytic anemia. There is no literature available regarding the identification of degradation impurities of mitapivat. The present study deals with the degradation behavior of mitapivat under various stress conditions such as hydrolytic, photolytic, thermal, and oxidative stress. The multivariate analysis found that the independent variables, that is, molarity, temperature, and time, are interacting with each other to affect the degradation of mitapivat. A specific, accurate, and precise high‐performance liquid chromatographic (HPLC) method was developed to separate mitapivat from its degradation products. The separation was achieved on the C‐18 column (250 mm × 4.6 mm × 5 µm) using the combination of 0.1% formic acid buffer and acetonitrile in gradient elution profile. The method was validated as per the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use Q2(R2) guideline. LC‐electrospray ionization‐Quadrupole‐time of flight was employed to identify degradation products. A total of seven novel degradation products of mitapivat were identified based on tandem mass spectrometry and accurate mass measurement. In‐silico toxicity of mitapivat and its degradation products was qualitatively evaluated by the DEREK toxicity prediction tool. [ABSTRACT FROM AUTHOR]

AbstractNucleosides and nucleobases in edible mushrooms collected from the Tekirdağ region of Turkey were determined by high performance liquid chromatography (HPLC). Separation of compounds was accomplished by gradient elution on a C18 column. A mixture of methanol (MeOH):50 mM sodium phosphate buffer (1:99, v/v) at pH 3.70 and methanol:50 mM sodium phosphate buffer (20:80) at pH 6.20 was used as the solvent. Two methods were used to treat the lyophilized mushrooms: ultrasound-assisted solid-liquid extraction (US-SLE) and pressurized (accelerated) solid-liquid extraction (PSLE). Deionized water was used as the extraction solvent. The extraction temperature and time were optimized. Fourteen nucleosides and nucleobases were simultaneously monitored at 254 nm within 25 min. Ultrasound-assisted solid-liquid was demonstrated to be more effective, perhaps because the pressurized liquid extraction system is a closed system and the matrix-solvent interaction may be insufficient. Adenosine, guanosine and uridine were the most abundant compounds in all studied mushrooms. [ABSTRACT FROM AUTHOR]

In this study, a rapid and sensitive ultra‐high performance liquid chromatography‐tandem mass spectrometry method was established for the simultaneous determination of four Vitexin‐4"‐O‐glucoside (VOG), Vitexin‐2"‐O‐rhamnoside (VOR), vitexin (VIT), and hyperoside (HP) in plasma, which are representative flavonoids constituents of hawthorn leaves. The four components were separated by CORTECS UPLC C18 column (100 × 3.0 mm, 1.6 µm), using acetonitrile‐water containing 0.02% formic acid and 2 mmol/L ammonium formate as the mobile phase, the gradient elution flow rate was 0.30 mL/min. The analyte was quantified using an electrospray ionization triple quadrupole mass spectrometer. The analytes and baicalin internal standard were performed at m/z 593.2/413.2 for VOG, m/z 577.2/413.1 for VOR, m/z 431.1/310.9 for VIT, m/z 463.2/300 for HP and m/z 445.1/269 for internal standard. Among the four flavonoids, the correlation coefficient of the standard curve of each component is between 0.9939 and 0.9987. After oral administration of hawthorn leaf extract, VOG and VOR showed similar pharmacokinetic characteristics; VIT was eliminated in the body more slowly than the other three flavonoids and distributed more in the tissues; HP can be quickly absorbed in the blood. The developed analytical method has high sensitivity, precision, and accuracy with no interference from plasma components and has been successfully used in pharmacokinetic studies. [ABSTRACT FROM AUTHOR]

The simultaneous determination of Mometasone furoate (MOM) and Olopatadine hydrochloride (OLO) in a combined dose has been developed and validated using a specific, precise, accurate, fast, reliable, and economical high‐performance liquid chromatography technique. Methanol:water:acetonitrile (20:25:55, v/v/v) was used as the mobile phase during the separation. The procedure was performed using a low‐pressure gradient elution on the reversed‐phase Phenomenex C18 column. At 238 nm, separated components were densitometrically measured. The flow rate was fixed at 1.0 mL/min with a continuous run up to 10 min, while the retention time was located near about 3.2 and 6.1 min for OLO and MOM, respectively. The method was validated for Linearity and range, precision, reproducibility, specificity, accuracy, limit of detection, limit of quantification, and robustness as per the International Council for Harmonization Q2(R1) guideline. MOM and OLO regression coefficients (r2) were found to be 0.9994 and 0.9997, over the range of 2.5–15 and 33.25–199.5 µg/mL, respectively. MOM and OLO percentage recoveries were measured to be 99.49 ± 0.14 and 99.98 ± 0.22, respectively. The method can be successfully applied for routine analysis of the quantitative determination of MOM and OLO in a combined dose. [ABSTRACT FROM AUTHOR]

A two-component model of gradient elution chromatography is investigated to theoretically study the effects of simultaneous variations in temperature and solvent strength on the retention behaviors of elution profiles in thermally insulated liquid chromatographic columns. The gradient elution technique is based on the gradual increase or decrease in eluent strength during the chromatographic operation by varying the composition of the mobile phase. The enthalpy of adsorption is primarily responsible for internal temperature variations inside the column, as heat adsorbs during the adsorption process and releases in the desorption phase. Both types of variations change the propagation speeds of moving pulses inside the column which can lead to better separation of the components and a reduction in the recycling time for the next injection. The equilibrium dispersive model (EDM) coupled with the energy balance equation for temperature and transport equation for the volume fraction of the solvent is utilized to simulate this complex process. The resulting nonlinear model equations are approximated by applying a semi-discrete second-order finite volume scheme. The numerical solutions are used to study the impact of a gradient starting and ending times, volume-fraction of the solvent, solvent strength parameter, the slope of gradient, enthalpy of adsorption, injection temperature, and the ratio of specific heats on the concentration profiles. [ABSTRACT FROM AUTHOR]

Background The topical veterinary drug product containing fipronil and permethrin provides an effective repellent protection and high insecticidal efficacy for dogs. Objective The objective of this study was to develop a stability-indicating high-performance liquid chromatography (HPLC) method for simultaneous detection and quantification of fipronil, permethrin, their key degradation products, and butylated hydroxytoluene (BHT) in a topical drug product. Method The two active ingredients, their degradation products, and the antioxidant (BHT) were separated by a gradient elution on a Phenomenex Kinetex C18 column (150 × 3 mm, 2.6 µm particle size) maintained at 37°C with H2O “acetonitrile “isopropyl alcohol “85% H3PO4 (65.5 + 32.5 + 4/0.0053, v/v/v/v) as mobile phase A and acetonitrile (100%) as mobile phase B. The flow rate was 0.9 mL/min, and analytes were detected and quantified at 235 nm. Results The specificity of the method was demonstrated by adequate separation of fipronil, permethrin, their degradation products, and BHT in the forced degraded finished product. The linearity of the method was demonstrated in the range of 0.2% to 150% of target analytical concentration of both active ingredients and 50% to 150% for BHT. Excellent recoveries of fipronil, permethrin, and BHT in placebo spiked active ingredient solutions in the linearity range showed sufficient accuracy of the method. The LOQ and LOD of the method were determined to be 0.2% and 0.07% of the analytical concentration. A robustness study did not identify any critical parameter that adversely affected the separation and quantification. Conclusions Here, we report the development and validation of a robust, stability-indicating HPLC method for identification and assay of fipronil, permethrin, and BHT, including estimation of fipronil's and permethrin's degradation products in a topical drug product for dogs. Highlights The new HPLC method permits the acquisition of data for all analytes of interest for a topical finished drug product containing fipronil, permethrin, and BHT. [ABSTRACT FROM AUTHOR]

Background Fipronil is a commonly used pesticide in the agricultural and animal health industries for the protection of crops and control of fleas, ticks, and chewing lice. It is difficult to obtain reproducible retention time and relative retention time (RRT) for a common hydrolytic degradation product of fipronil with the current European Pharmacopeia (EP) monograph for assay and estimation of related substances of fipronil. This situation causes misidentification, mislabeling, and/or false out-of-specification results for this hydrolytic degradation product of fipronil in bulk commercial batches during batch release and/or in the stability samples during the shelf life of a released batch. Objective This study aimed to develop a reversed-phase ultra performance liquid chromatography (UPLC) method for assay and identification of fipronil including identification and estimation of its related substances in bulk drug substance batches of fipronil and provide consistent retention time of the hydrolytic degradation product. Methods Fipronil and its related substances were separated by gradient elution on a Halo C18 column (50 mm × 2.1 mm id, 2.0 µm particle size) maintained at 40°C with 0.1% H3PO4 in H2O as mobile phase-A and acetonitrile–methanol (50 + 50, v/v) as mobile phase-B. Fipronil and its related substances were detected and quantified at 280 nm with a quantitation limit of 0.05% of the target (analytical) concentration. Results The UPLC method was able to separate all analytes of interest by gradient elution with a total run time of 7 min (approximately 40% faster than EP). Conclusion In this paper, we report the development and validation of a fast, stability-indicating reversed-phase UPLC method for assay and estimation of related substances of fipronil in stability samples and bulk batches of fipronil. Highlights The new UPLC method is approximately 40% faster than the current Ph. Eur. monograph for fipronil assay and the new method provides reproducible retention of a common hydrolytic degradation product of fipronil. [ABSTRACT FROM AUTHOR]

A HPLC method was developed for the simultaneous determination of euscaphic acid, 2α,19α-dihydroxy-3-oxo-urs-12-en-28-oic acid, maslinic acid, corosolic acid, oleanic acid, and ursolic acid in Malus doumeri fruits. Analyses were conducted on the distribution and content of these six triterpenic acids in Malus doumeri fruits from six producing areas in Guangxi. Using gradient elution at a flow rate of 0.8 mL/min, a Diamonsil C18 (2) column was used with a mobile phase of 0.1% formic acid aqueous solution/methanol (v/v). The detection wavelength was 210 nm and the column temperature was 30 °C. The results showed that the mass concentrations of the six triterpenic acids had a good linear relationship with the chromatographic peak areas in the linear range. The correlation coefficients were greater than 0.9990, the detection limits were within 0.46-2.00 μg/mL, the lower quantitation limits were within 1.53-6.67 μg/mL, the coefficients of variation were less than 5.0%, and the recovery percentages were within 99.2%-101.3%. Six samples from different production areas contained six triterpenic acids (euscaphic acid, 2α,19α-dihydroxy-3-oxo-urs-12-en-28-oic acid, maslinic acid, corosolic acid, oleanic acid, and ursolic acid). Each of the six triterpenic acids was a pentacyclic triterpenic acid. Among the six triterpenic acids, euscaphic acid and 2α,19α-dihydroxy-3-oxo-urs-12-en-28-oic acid were first detected in Malus doumeri fruits. Ursolic acid, euscaphic acid, and 2α,19α-dihydroxy-3-oxo-urs-12-en-28-oic acid were predominant, accounting for 71.82%-81.38% of the total triterpenic acids. The total triterpenic acids content ranged from 808.74 to 1090.75 μg/g FM. The total triterpenic acids content of fruits from Liujiang district of Liuzhou and Pingle of Guilin were relatively high, reaching 1090.75 μg/g FM and 1045.20 μg/g FM, respectively. Overall, this study's HPLC method can detect the triterpenic acids content of Malus doumeri fruits and provide scientific references for the quality evaluation of Malus doumeri fruit's raw materials and products. [ABSTRACT FROM AUTHOR]

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Rationale: Nirmatrelvir is a protease inhibitor that is essential for virus replication. Nirmatrelvir is indicated for the management of mild to severe cases of COVID‐19 in individuals who are 12 years of age or older. Forced degradation studies of nirmatrelvir were carried out on the drug substance in solid and solution forms, subjecting it to various stress conditions according to International Conference on Harmonisation (ICH) Q1A(R2) and Q1B guidelines. The analytical method was validated as per the ICH Q2(R1) guidelines. Methods: The drug substance (nirmatrelvir) was subjected to hydrolysis (acidic, alkaline, and neutral), thermal, photolytic, and oxidative stress conditions. Five degradation products (DPs) of nirmatrelvir formed under hydrolytic (acidic and alkaline) and oxidative (2,2‐azobisisobutyronitrile) stress conditions. These degradation products were identified and separated using reverse‐phase HPLC on a phenomenex kinetex C8 column (250 mm × 4.6 mm × 5 μm) with gradient elution. The mobile phase consisted of 0.1% formic acid and acetonitrile, and detection was carried out at a wavelength of 210 nm. Results and conclusions: Nirmatrelvir and its five DPs were efficiently separated using reverse phase–HPLC. These five DPs were identified and characterized using LC‐electrospray ionization (ESI)‐Q‐TOF‐coupled mass spectrometry analysis in the ESI‐positive ionization mode. The formation mechanisms of the DPs and the most probable mass fragmentation pathways for both nirmatrelvir and its DPs were elucidated. The developed method demonstrated selectivity, accuracy, linearity, and reproducibility, making it appropriate for quality control of nirmatrelvir and future research studies. Additionally, the physicochemical and Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) properties of nirmatrelvir and its DPs were predicted using ADMET predictor software. The toxicity profile revealed that DP2 and DP3 have teratogenic effects while DP1 and DP3 caused phospholipidosis. [ABSTRACT FROM AUTHOR]

A method was established to simultaneously determine 2'-fucosyllactose (2'-FL) and lactose-N-neotetraose (LNnT) in infant milk powder by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS). The sample was extracted by water, precipitated protein, and purified through a needle-type water system filtration membrane. Then the sample solution was separated using an amide column by gradient elution, within acetonitrile and 10 mmol/ L ammonium formate aqueous solution (containing 0.1% formic acid, V/V). The selective reaction monitoring mode was used to measure and quantify by external standards. In addition, it also evaluated the solvent effect and matrix effect by dilution method and extraction addition respectively. Results showed that the addition ion peaks [M + NH4+] and [M + H+ ] of 2'-FL and LNnT in the positive ion mode were better than others. After the gradient conditions and flow rate optimization, both 2'-FL and LNnT could be eluted within 8 min. However, it was found that 2'-FL and LNnT had serious solvent effects, while, in the elimination test, the effect could be eliminated using 50% acetonitrile ammonium formate aqueous solution as the diluted solvent, within 20 times dilution. The linear ranges of 2'-FL and LNnT were 5. 0 - 150.0 ng/ mL and 2.5 - 75.0 ng/ mL, respectively. And there was no matrix effect in either 2'-FL or LNnT. The method verification showed that the precision and accuracy parameters of 2'-FL and LNnT met the requirements of the national standard, and this method was suitable for the simultaneous determination of 2'-FL and LNnT in infant formula. [ABSTRACT FROM AUTHOR]

This article discusses the synthesis and characterization of 3-triazinyl-7-aminocoumarins, which are important compounds with various applications. The authors explore different synthetic approaches and find that a C–H/C–H cross-coupling method using heptafluorobutyric acid as a catalyst is a more straightforward and environmentally-friendly approach. They optimize the reaction conditions and identify the best conditions for synthesis. The article also provides detailed information on the physical and chemical properties of various compounds, including their spectroscopic data and yields. Supporting information is available online. [Extracted from the article]

Propolis is a resinous bee product with a very complex composition, which is dependent upon the plant sources that bees visit. Due to the promising antimicrobial activities of red Brazilian propolis, it is paramount to identify the compounds responsible for it, which, in most of the cases, are not commercially available. The aim of this study was to develop a quick and clean preparative-scale methodology for preparing fractions of red propolis directly from a complex crude ethanol extract by combining the extractive capacity of counter-current chromatography (CCC) with preparative HPLC. The CCC method development included step gradient elution for the removal of waxes (which can bind to and block HPLC columns), sample injection in a single solvent to improve stationary phase stability, and a change in the mobile phase flow pattern, resulting in the loading of 2.5 g of the Brazilian red propolis crude extract on a 912.5 mL Midi CCC column. Three compounds were subsequently isolated from the concentrated fractions by preparative HPLC and identified by NMR and high-resolution MS: red pigment, retusapurpurin A; the isoflavan 3(R)-7-O-methylvestitol; and the prenylated benzophenone isomers xanthochymol/isoxanthochymol. These compounds are markers of red propolis that contribute to its therapeutic properties, and the amount isolated allows for further biological activities testing and for their use as chromatographic standards. [ABSTRACT FROM AUTHOR]

Glutathione (GSH) is an important antioxidant that is generated and degraded via the GSH cycle. Quantification of the main components in the GSH cycle is necessary to evaluate the process of GSH. In this study, a robust ultra‐performance liquid chromatography‐tandem mass spectrometry method for the simultaneous quantification of 10 components (GSH; γ‐glutamylcysteine; cysteinyl‐glycine; n‐acetylcysteine; homocysteine; cysteine; cystine; methionine; glutamate; pyroglutamic acid) in GSH cycle was developed. The approach was optimized in terms of derivative, chromatographic, and spectrometric conditions as well as sample preparation. The unstable thiol groups of GSH, γ‐glutamylcysteine, cysteinyl‐glycine, n‐acetylcysteine, cysteine, and homocysteine were derivatized by n‐ethylmaleimide. The derivatized and underivatized analytes were separated on an amino column with gradient elution. The method was further validated in terms of selectivity (no interference), linearity (R2 > 0.99), precision (% relative standard deviation [RSD%] range from 0.57 to 10.33), accuracy (% relative error [RE%] range from ‐3.42 to 10.92), stability (RSD% < 5.68, RE% range from ‐2.54 to 4.40), recovery (RSD% range from 1.87 to 7.87) and matrix effect (RSD% < 5.42). The validated method was applied to compare the components in the GSH cycle between normal and oxidative stress cells, which would be helpful in clarifying the effect of oxidative stress on the GSH cycle. [ABSTRACT FROM AUTHOR]

In this paper, a simple and efficient high‐performance liquid chromatography method was established to analyze the chemical composition fingerprint of Centellae Herba (CHA) and determine five triterpenoid active components in CHA, namely, asiaticoside B (AB), madecassoside, asiaticoside, madecasic acid, and asiaticoic acid. The separation of the compounds was carried out on an XD‐C18 column (250 mm × 4.6 mm, 5 µm), the wavelength of the ultraviolet detector was set to 205 nm, and the mobile phase was composed of acetonitrile −0.05% phosphoric acid, 2 mmol/L β‐cyclodextrin aqueous solution, and gradient elution at the flow rate of 1.0 mL/min. A general chromatographic fingerprint consisting of 20 characteristic peaks of 18 batches of CHA samples was established, and the samples were classified and evaluated by similarity analysis, hierarchical cluster analysis, and principal component analysis combined with multivariate econometric analysis. In quantitative analysis, all calibration curves showed good linear regression in the test range (r > 0.999), the average recovery was 96.12%–104.63%, and the relative standard deviations of repeatability and stability were less than 2.00%. The results show that the method is accurate and effective and can be used for the comprehensive quality control of CHA. [ABSTRACT FROM AUTHOR]

A comprehensive analytical method based on liquid chromatography–tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous detection of 12 mushroom toxins (ibotenic acid, muscimol, muscarine, β-amanitin, α-amanitin, desoxoviroidin, γ-amanitin, phallisacin, illudin S, phallacidin, phalloidin and illudin M) in mushrooms, serum, urine and simulated gastric fluid. The samples were extracted with water or acetonitrile solution, and the serum sample was further purified with PSA sorbent. Chromatographic separation was performed on an ACQUITY UPLC HSS T3 column with gradient elution using methanol and water containing 1 mM ammonia fluoride as a mobile phase. Mass spectrometric acquisition was performed in electrospray positive ionization mode. Good linearities (R2 > 0.994) were obtained for 12 toxins over the range of 0.05~200 µg/L. Matrix-matched calibration curves were used for quantification. The method limits of quantification were 0.01~0.2 mg/kg for mushrooms and 0.15~2.0 µg/L for three biological liquid samples. The mean recoveries of 12 target toxins (spiked at three concentration levels) ranged from 73.0% to 110.3%, with relative standard deviations not exceeding 19.4%, which meets the requirements for the determination of trace compounds in a biological matrix. This method was applied to the analysis of mushroom samples from Yunnan Province. As a result, 11 toxins, not including illudin M, were detected with a concentration range of 0.61~2143 mg/kg. [ABSTRACT FROM AUTHOR]

Animal venoms are intricate and teem with potential for groundbreaking medical advancements. Although traditional methods for purifying venom proteins are effective, they usually require complicated, multi-step processes that lead to lower yields. Our study introduces an efficient, one-step technique for extracting venom-derived proteins through reverse-phase high-performance liquid chromatography (RP-HPLC). We carefully optimized the RP-HPLC process, focusing on the gradient elution conditions and the strategic use of our columns' stationary phase characteristics, to enhance the effectiveness of our separations. This enabled us to efficiently isolate six venom proteins: melittin (2.846 kDa) from Apis mellifera with a yield of 4.5% and homogeneity of 99%; α-cobratoxin (7.821 kDa) from Naja kaouthia with a yield of 15% and homogeneity of 99%; α-bungarotoxin (7.983 kDa) from Bungarus multicinctus with a yield of 7% and purity of 99%; calciseptine (7.035 kDa) from Dendroaspis polylepis with a yield of 6% and homogeneity of 95%; notexin (13.593 kDa) from Notechis scutatus with a yield of 10% and homogeneity of 95%; and CVFm (150 kDa) from Naja melanoleuca with a yield of 0.8% and homogeneity of 94%. These were all accomplished in one step. This breakthrough simplifies the purification of venom peptides and proteins, making the process more feasible and economical. It paves the way for developing new drugs and promising treatments that are both more effective and precisely targeted. [ABSTRACT FROM AUTHOR]

Indoxyl sulfate (IxS) and p-cresyl sulfate (pCS) are toxic uremic compounds with documented pathological outcomes. This review critically and comprehensively analyzes the available liquid chromatography-mass spectrometry methods quantifying IxS and pCS in human matrices and the biological applications of these validated assays. Embase, Medline, PubMed, Scopus, and Web of Science were searched until December 2023 to identify assays with complete analytical and validation data (N = 23). Subsequently, citation analysis with PubMed and Scopus was utilized to identify the biological applications for these assays (N = 45). The extraction methods, mobile phase compositions, chromatography, and ionization methods were evaluated with respect to overall assay performance (e.g., sensitivity, separation, interference). Most of the assays focused on human serum/plasma, utilizing acetonitrile or methanol (with ammonium acetate/formate or formic/acetic acid), liquid–liquid extraction, reverse phase (e.g., C18) chromatography, and gradient elution for analyte separation. Mass spectrometry conditions were also consistent in the identified papers, with negative electrospray ionization, select multiple reaction monitoring transitions and deuterated internal standards being the most common approaches. The validated biological applications indicated IxS and/or pCS were correlated with renal disease progression and cardiovascular outcomes, with limited data on central nervous system disorders. Methods for reducing IxS and/or pCS concentrations were also identified (e.g., drugs, natural products, diet, dialysis, transplantation) where inconsistent findings have been reported. The clinical monitoring of IxS and pCS is gaining significant interest, and this review will serve as a useful compendium for scientists and clinicians. [ABSTRACT FROM AUTHOR]

Yeokwisan (YWS) is an herbal medicine prescription consisting of six oriental herbal medicines, developed to treat reflux esophagitis. We focused on developing an analytical method capable of simultaneously quantifying 13 compounds in YWS samples using high-performance liquid chromatography–photodiode array detection (HPLC–PDA) and ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) and exploring their antioxidant effects. All compounds examined in both analytical systems were chromatographically separated on a SunFireTM C18 (4.6 × 250 mm, 5 μm) column and an Acquity UPLC BEH C18 (2.1 × 100 mm, 1.7 μm) column using gradient elution of a water–acetonitrile mobile phase. Antioxidant effects were evaluated based on radical scavenging activity (DPPH and ABTS tests) and ferrous ion chelating activity. In two analytical methods, the coefficient of determination of the regression equation was ≥0.9965, the recovery range was 81.11–108.21% (relative standard deviation (RSD) ≤ 9.33%), and the precision was RSD ≤ 11.10%. Application of the optimized analysis conditions gave quantitative analysis results for YWS samples of 0.02–100.36 mg/g. Evaluation of the antioxidant effects revealed that baicalein and baicalin exhibit significant antioxidant activity, suggesting that they play an important role in the antioxidant effects of YWS. [ABSTRACT FROM AUTHOR]

Itampolin A, a natural brominated tyrosine alkaloid isolated from the sponge Iotrochota purpurea, has been shown to have good inhibitory effects in lung cancer cells as a p38α inhibitor. A simple, sensitive, and reliable ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) method has been established, validated, and applied to the study of the pharmacokinetics and tissue distribution of itampolin A following intragastric and intravenous administration. Itampolin A and theophylline (internal standard, IS) were extracted by the simple protein precipitation technique using methanol as the precipitating solvent. Chromatographic separation was achieved by using the optimized mobile phase of a 0.1% formic acid aqueous solution and acetonitrile in the gradient elution mode. Itampolin A and IS were detected and quantified using positive electrospray ionization in the multiple reaction monitoring mode with transitions of m/z 863.9 → 569.1 for itampolin A and m/z 181.1 → 124.1 for IS, respectively. The assay exhibited a linear dynamic range of 1–1600 ng/mL for itampolin A in biological samples and the low limit of quantification was 1 ng/mL. Non-compartmental pharmacokinetic parameters indicated that itampolin A was well-absorbed into the systemic circulation and rapidly eliminated after administration. The apparent distribution volume of itampolin A was much higher after intragastric administration than that after intravenous administration. A tissue distribution study showed that itampolin A could be detected in different tissues and maintained a high concentration in the lung, which provided a material basis for its effective application in lung cancer. The pharmacokinetic process and tissue distribution characteristics of imtapolin A were expounded in this study, which can provide beneficial information for the further research and clinical application of itampolin A. [ABSTRACT FROM AUTHOR]

Four sample preparation techniques, namely direct protein precipitation through a) trichloroacetic acid addition (PPA) or b) acetonitrile addition (PPO), c) liquid-liquid extraction in n-octanol followed by the direct injection of the organic layer, and d) supramolecular solvent extraction in a tetrahydrofuran/n-octanol/water coacervate (SUPRAS) were evaluated to be used for the RPLC/DAD assay of carbamazepine in human plasma samples, targeting therapeutic monitoring (TM) purposes. The chromatographic approach to separating carbamazepine from human plasma matrices was designed to be a simple gradient elution with an octadecyl chemically modified silica gel stationary phase, and a mobile phase composed of acetonitrile (organic) and HPLC grade water (aqueous), both with 0.1% formic acid. Monitoring at 290 nm allowed for the detection of carbamazepine. After optimizing both sample preparation procedures and chromatographic separation parameters, LOQ values of 3 µg/mL (PPA), 0.6 µg/mL (PPO), 12 ng/mL (LLE) and 50 ng/mL (SUPRAS) were determined. Detector response functions were studied over an interval up to 20 µg/mL (ULOQ). [ABSTRACT FROM AUTHOR]

In this study, a combination approach involving macroporous resin (MR) column chromatography and gradient countercurrent chromatography (CCC) was employed to enrich and purify bufadienolides from the roots and rhizomes of Helleborus thibetanus Franch. Initially, a D101 MR‐packed column chromatography was utilized for fractionation and enrichment of the bufadienolides, which were effectively eluted from the column using a 60% ethanol solution. CCC was subsequently introduced to separate the enriched product using the ethyl acetate/n‐butanol/water (EBuWat, 4:1:5, v/v) and EBuWat (5:0:5, v/v) solvent systems in a gradient elution mode. As results, five bufadienolides, including 6.1 mg of hellebrigenin‐3‐O‐β‐D‐glucoside (1), 2.2 mg of tigencaoside A (2), 8.3 mg of deglucohellebrin (3), 3.5 mg of 14 β‐hydroxy‐3β‐[β‐D‐glucopyranosyl‐(1→6)‐(β‐D‐glucopyranosyl)oxy]‐5α‐bufa‐20,22‐dienolide (4), and 3.0 mg of 14β‐hydroxy‐3β‐[(β‐D‐glucopyranosyl)oxy]‐5α‐bufa‐20,22‐dienolide (5), were effectively separated from 300 mg of the enriched product. The respective high‐performance liquid chromatography purities were as follows: 95.2%, 75.8%, 85.7%, 82.3%, and 92.8%. This study provides valuable insights for the efficient enrichment and separation of bufadienolides from Helleborus thibetanus Franch. [ABSTRACT FROM AUTHOR]

The phytochemical composition of Asphodelus aestivus Brot., a plant with therapeutic properties in traditional medicine, remains largely unexplored, particularly in the specific environmental conditions of Jordan. This study utilized advanced LC-MS techniques to comprehensively analyze the secondary metabolites of a plant species endemic to Jordan. The development of the LC-MS method involved optimizing parameters such as solvent composition, gradient elution, and ionization techniques to achieve comprehensive metabolite profiling. The method was validated to ensure accurate, precise, sensitive, and specific identification and quantification of the compounds. Our analysis identified seven distinct compounds, including both familiar molecules and more complex anthrones and glycosides. This finding emphasizes the wide range of chemical compounds found in the plant and highlights the distinct chemical variations influenced by regional environmental factors. These findings contribute to our understanding of Asphodelus aestivus Brot. and highlight the potential therapeutic uses of its distinct phytochemical composition. This research makes a significant contribution to the field of plant-based natural products by combining modern analytical methods with traditional medicinal knowledge to investigate the complex phytochemical composition of Asphodelus aestivus. [ABSTRACT FROM AUTHOR]

The adsorption characteristics of β-glucooligosaccharides on activated carbon and the purification were systematically investigated. The maximum adsorption capacity of activated carbon reached 0.419 g/g in the optimal conditions. The adsorption behavior was described to be monolayer, spontaneous, and exothermic based on several models' fitting results. Five fractions with different degrees of polymerization (DPs) and structures of β-glucooligosaccharides were obtained by gradient ethanol elution. 10E mainly contained disaccharides with dp2a (G1→6G) and dp2b (G1→3G). 20E possessed trisaccharides with dp3a (G1→6G1→3G) and dp3b (G1→3G1→3G). 30E mainly consisted of dp3a and dp4a (G1→3G1→3(G1→6)G), dp4b (G1→6G1→3G1→3G), and dp4c (G1→3G1→3G1→3G). In addition to tetrasaccharides, 40E and 50E also contained pentasaccharides and hexasaccharides with β-(1→3)-linked or β-(1→6)-linked glucose residues. All fractions could inhibit the accumulation of intracellular reactive oxygen species (ROS) in H2O2-induced Caco-2 cells, and they could improve oxidative stress damage by increasing the activity of superoxide dismutase (SOD) and reduced glutathione (GSH), which were related to their DPs and structures. 50E with high DPs showed better anti-oxidative stress activity. [ABSTRACT FROM AUTHOR]

A high-performance liquid chromatography with diode array detector (HPLC-DAD) analytical method was developed for the simultaneous detection of 17 phenolic compounds, including phenols, chlorophenols, alkylphenols, and nitrophenols, in two types of water matrices: wastewater and surface water. Prior to HPLC-DAD determination, a solid-phase extraction (SPE) procedure was optimized. The proposed method uses multiwavelength analysis, with the optimum detection wavelengths selected as 268 nm, 280 nm, 386 nm, 304 nm, and 316 nm. The highest resolution was achieved using a chromatographic column, Eclipse XDB-C18 (150 × 4.6 mm, 5 μm), which was kept at 20 °C. The mobile phase consisted of a gradient elution program, with mobile phase A being a 0.1% H3PO4 aqueous solution and mobile phase B being acetonitrile. The flow rate was set at 0.6 mL/min. The 17 target phenolic compounds were fully separated in less than 27 min. All compounds showed good linear regression, with correlation coefficients higher than 0.999. The method's quantitation limits ranged from 4.38 to 89.7 ng/L for surface water and 7.83 to 167 ng/L for wastewater. The recovery rates were in the range of 86.2–95.1% for surface water and 79.1–86.3% for wastewater. The SPE-HPLC-DAD method was proven to be fast, sensitive, accurate, and reproducible. The developed method was successfully applied for the analysis of the 17 phenolic compounds in real surface water and wastewater samples, with phenol, 2,4-DNP, and 2,4-DNP being determined at levels greater than the method's limits of quantitation (LOQs). The proposed analytical method represents an original technical resource for the simultaneous determination of 17 phenolic compounds in environmental water matrices. [ABSTRACT FROM AUTHOR]

Using the Design of Experiments methodology (Response-Surface Methodology and Derringer's Desirability Function), a simple, fast and robust RP-HPLC method was developed for the analysis of enrofloxacin (EFC), its impurity A (fluoroquinolonic acid, FQ) and impurity B (ciprofloxacin, CPX). Gradient elution of samples was performed on a Zorbax Eclipse XDB C18 column (150 × 4.6 mm, 3.5 μm) with a mobile phase consisting of 32 mM phosphate buffer pH 3.5 – methanol (0 min-19.6% methanol; 15.5 min-19.6% methanol; 29.5 min-80% methanol; 30 min-19.6% methanol; 35 min-19.6% methanol), delivered at a flow rate of 1.5 mL min−1, wavelength of detection 278 nm (for EFX and CFX) and 265 nm for FQ. A good linear response was achieved in the range 15–35 μg mL−1 (EFX) and LOQ-150% for impurities (CFX and FQ). Other validation parameters were also tested: precision, accuracy, sensitivity and robustness. The developed method was shown to be simple, practical and suitable for the analysis of EFC and its impurities (CPX, FQ) in veterinary drugs. [ABSTRACT FROM AUTHOR]

A rapid and simple method for the determination of stearic acid and 12-hydroxystearic acid in PEG-60 hydrogenated castor oil by high performance liquid chromatography with evaporative light scattering detection was established. The oil sample was first pretreated by alkaline hydrolysis. The analysis was performed on a Zhongpu Develop XD-C18 column (250 mm × 4.6 mm, 5 µm) with gradient elution of methanol and 1% acetic acid aqueous solution at a flow rate of 1.2 mL·min−1 and a column temperature of 40 °C. The drift tube temperature of the evaporative light scattering detection system was set at 40 °C, and the pressure of carrier gas (N2) was 337 kPa. The regression equation revealed a good linear relation (r = 0.9993–0.9995) during the test ranges (119.1–1190.7 μg·mL−1 for 12-hydroxystearic acid, 10.7–107.4 μg·mL−1 for stearic acid). The detection limits of 12-hydroxystearic acid and stearic acid were 1.1 and 2.5 μg·mL−1, the limits of quantitation were 3.2 and 7.4 μg·mL−1, respectively. And the mean recoveries were 101.5 and 101.0%, the corresponding relative standard deviations (RSDs) were 2.1 and 2.8%, respectively. The RSDs corresponding to repeatability (n = 6) were both less than 1.7% in terms of precision. As to the stability, the test results remained stable after 8 h at room temperature (RSDs were both less than 2.6%). The developed method showed high sensitivity, recovery, repeatability and stability, which indicated that the method could be applied as a quality evaluation method for the determination of stearic acid and 12-hydroxyoctadecanoic acid in PEG-60 hydrogenated castor oil. [ABSTRACT FROM AUTHOR]

In this study, a UPLC-MS/MS method was developed for determination of pancratistatin in the mouse blood, and the pharmacokinetics of pancratistatin in mice after intravenous (5 mg kg−1) and intragastric (15 mg kg−1) administration was studied. HSS T3 column was used for separation with mobile phases of acetonitrile and 0.1% formic acid using gradient elution procedure. The blood sample was treated by protein precipitant with acetonitrile, midazolam was used as internal standard (IS). Multiple reaction monitoring mode (MRM) was used for quantitative analysis, m/z 326.2→83.8 for pancratistatin and m/z 326.2→291.4 for IS in electrospray (ESI) positive interface. It showed a good linear in the range of 10–4,000 ng mL−1 (r > 0.998); the intra-day and inter-day precision was <15%, and the accuracy was 93%–105%. The recovery was better than 82%, and the matrix effect was 94%–105%. The developed UPLC-MS/MS method was fast, selective, and suitable for the pharmacokinetics of pancratistatin in mice. [ABSTRACT FROM AUTHOR]

An ultra performance liquid chromatography-quadrupole-time-flight mass spectrometric method was developed for the simultaneous screening and determination of 9 nitrobenzene compounds, including nitrobenzene (NB), 3, 4-dinitrotoluene (3, 4-DNT), 2, 3-dinitrotoluene (2, 3-DNT), 2, 4-dinitrotoluene (2, 4-DNT), 2, 6-dinitrotoluene (2, 6-DNT), 2, 5-dinitrotoluene (2, 5-DNT), 3, 5-dinitrotoluene (3, 5-DNT), 2-nitrotoluene (2-NT) and 1-chloro-4-nitrobenzene (ChNB) in cosmetics. Samples were extracted with ethyl acetate, and the extracts were further hydrogenated using 5% Pd/C catalyst. The target analytes were separated on a Poroshell 120 EC-C18 chromatographic column (100 mm × 4.6 mm, 2.7 μm). Gradient elution was carried out with 0.1% (VIV) formic acid aqueous solution and acetonitrile as the mobile phases. The eluent from the column was further detected using Q-tof MS with information dependent acquisition (Auto MS/MS) mode for MS data acquisition. A database, containing retention time, precise mass of parent ion, isotope abundance ratio and precise mass of fragment ion, was established for screening and confirming the nitrobenzene compounds. The quantitation analysis was carried out by extracting peak area with precise mass. Under optimal conditions, the analytes show good linear relationship within the range, with the correlation coefficient (r) not less than 0.999. The limits of detection are in the range of 0.01-0.3 mg/kg, and the limits of quantification are in the range of 0.04-2.0 mg/kg. Samples, such as cream, lotion, powder and lip balm, are fortified at three levels. The average spiked recoveries range from 85.2% to 113%, with the relative standard deviations (RSDs) ranging from 0.23% to 3.61%. The optimized method is accurate, sensitive, specific and suitable for the detection and screening of nitrobenzene compounds in cosmetics. [ABSTRACT FROM AUTHOR]

Blumea eriantha D.C is a weed from Asteraceae family and is reported to have anticancer activity. The essential oil from the aerial parts was extracted by steam distillation method with the yield of 0.36%. Through GC-MS analysis of the oil, seventeen compounds could be identified by comparing with linear retention indices with the library. Out of the seventeen compounds β-Caryophylline oxide was isolated by column chromatography with gradient elution and the structure was determined through FT-IR, MS, 1HNMR, 13 C NMR and DEPT. The oil was evaluated for its effect on angiogenesis using Chorioallantoic Membrane Assay (CAM Assay). The concentration dependent antiangiogenic effect was observed with IC 50 value of 19.28 ppm. [ABSTRACT FROM AUTHOR]

With the escalating demand for Astragalus polysaccharides products developed from Radix Astragali (RA), the necessity for quality control of polysaccharides in RA has become increasingly urgent. In this study, a specific method for the simultaneous determination of seven monosaccharides in polysaccharides extracted from Radix Astragali (RA) has been developed and validated using ultra-performance liquid chromatography equipped with an ultraviolet detector (UHPLC-UV) for the first time. The 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatizations were separated on a C18 column (Waters ACQUITYTM, Milfor, MA, USA, 1.8 µm, 2.1 × 100 mm) using gradient elution with a binary system of 5 mm ammonium formate (0.1% formic acid)-acetonitrile for 24 min. Additionally, seven monosaccharides showed good linear relationships (R2, 0.9971–0.9995), adequate precision (RSD < 4.21%), and high recoveries (RSD < 4.70%). The established method was used to analyze 109 batches of RA. Results showed that the Astragalus polysaccharides (APSs) mainly consist of mannose (Man), rhamnose (Rha), glucose (Glu), galactose (Gal), arabinose (Ara), xylose (Xyl); and fucose (Fuc); however, their composition was different among RA samples from different growth patterns, species, growth years, and origins, and the growth mode of RA and the age of wild-simulated RA can be accurately distinguished by principal component analysis (PCA). In addition, the immunological activity of APSs were also evaluated jointly by measurement of the NO release with RAW264.7, with the results showing that APSs have a promoting effect on the release of NO and exhibit a significant correlation with Man, Glu, Xyl, and Fuc contents. Accordingly, the new established monosaccharides analytical method and APS-immune activity determination in this study can provide a reference for quality evaluation and the establishment of quality standards for RA. [ABSTRACT FROM AUTHOR]

SIPI6398 is a novel anti-schizophrenia agent with a new mechanism of action and demonstrates better target selectivity and safety compared to its competitors. However, few in vivo studies on the pharmacokinetics and bioavailability of SIPI6398 have been performed. A rapid and simple ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach was developed for accurate quantification of SIPI6398 in rat plasma. A simple protein precipitation of acetonitrile-methanol (9 : 1, v/v) was used to treat plasma. Chromatography was performed on a UPLC HSS T3 column (50 mm × 2.1 mm, 1.8 μm) at a flow rate of 0.4 ml/min. The mobile phase consisted of acetonitrile-water (with 0.1% formic acid) and gradient elution was used, and the elution time was 4 minutes. Quantitative analysis was performed using electrospray ionization (ESI) in positive ion detection mode with multiple reaction monitoring (MRM) mode. To evaluate the pharmacokinetics and bioavailability, SIPI6398 was administered to rats in two different ways: oral (4 mg/kg) and intravenous (2 mg/kg) administration. The calibration curve for the UPLC-MS/MS approach shows excellent linearity in the range of 1–2000 ng/mL with an r value above 0.99. The precision, accuracy, recovery, matrix effect, and stability results all meet the criteria established for biological analytical methods. The UPLC-MS/MS method was successfully applied it to pharmacokinetics study of SIPI6398. The bioavailability of SIPI6398 was calculated to be 13.2%. These studies have the potential to contribute towards a more comprehensive comprehension of the pharmacokinetics and bioavailability of SIPI6398. [ABSTRACT FROM AUTHOR]