Sensitive High-performance Liquid Research Articles

Determination of Nemonoxacin in Small Volumes of Rat Plasma and Bile by a Novel HPLC-Fluorescence Assay and Its Application to Disposition and Biliary Excretion Kinetics.

Nemonoxacin is a novel non-fluorinated quinolone antibiotic for the treatment of community-acquired pneumonia. To investigate the pharmacokinetics (PK) of nemonoxacin, a simple and sensitive high-performance liquid chromatography assay (HPLC) was needed. An HPLC method with fluorescence (FL) detection was developed for the quantification of nemonoxacin in plasma and bile. Ultraviolet (UV) and FL characteristics were examined for the optimal detection conditions. Nemonoxacin and the internal standard gatifloxacin were extracted from plasma utilizing ethyl acetate-isopropanol (70/30, v/v). For bile sample preparation, direct dilution with the mobile phase buffer was used. Chromatographic separation was achieved on a C6-phenyl column (5μm, 25 cm × 4.6 mm i.d.) at 30 °C with a flow rate of 1 mL/min. The mobile phase was composed of methanol and 50mM potassium dihydrogen phosphate containing 0.5% (v/v) triethylamine (pH 7.5) (45/55 and 35/65 (v/v) for plasma and bile samples, respectively). FL was measured at an emission wavelength of 465 nm with excitation at 285 nm. The calibration curves were linear with a lower limit of quantification of 5 and 100 ng/mL in a small volume of plasma (50μL) and bile (10μL). The intra- and inter-day precision was within 9.0% and the accuracy was within 7.6% deviation of the nominal concentration. Nemonoxacin was stable under various storage/handling conditions tested. The method was successfully employed to describe the plasma and biliary profiles of nemonoxacin in rats following a single intravenous dose of 1 mg/kg. Nemonoxacin displayed two-compartment disposition kinetics. The bile-to-plasma area under concentration-time curve ratio (AUCbile/plasma) estimated was 50.7, indicating that nemonoxacin was actively secreted into bile. A validated method was developed and found to be specific, precise and accurate. The applicability of this proposed method was substantiated in pharmacokinetic studies in rats.

Individualized medication of venetoclax based on therapeutic drug monitoring in Chinese acute myeloid leukemia patients using an HPLC method.

The aim of this study was to establish a simple and sensitive high-performance liquid chromatography method for therapeutic drug monitoring of venetoclax (VEN) and optimize regimens. The analysis required the extraction of a 50 μl plasma sample and the precipitation of proteins using acetonitrile extraction. The chromatographic method employed a mobile phase of acetonitrile: 0.5% KH 2 PO 4 (pH 3.5) (60/40, v/v) on a Diamond C 18 (4.6 mm × 250 mm, 5 μm) column at a flow rate of 1.0 ml/min. The quantitative method was validated based on standards described in 'Bioanalytical Method Validation: Guidance for Industry' published by the US Food and Drug Administration (FDA). The calibration curve was linear ( R2 = 0.9998) over the range of 75-4800 ng/ml, with limits of quantification of 25 ng/ml. The coefficients of intraday and interday validation, specificity, recovery, and stability all met the criteria of FDA guidance. The method was successfully applied to analyze VEN concentrations in 30 cases of acute myeloid leukemia patients. The peak concentration ( Cmax ) was 1881.19 ± 756.61 ng/ml, while the trough concentration ( Cmin ) was 1212.69 ± 767.92 ng/ml in acute myeloid leukemia patients. Our study establishes a simple, precise, and sensitive high-performance liquid chromatography method for monitoring VEN and confirms its applicability for therapeutic drug monitoring of VEN in hematological cancers.

RP-HPLC-PDA-Based Simultaneous Estimation of Ramipril and Hydrochlorothiazide in Combined Dosage Forms: A Validated Approach

A rapid, highly sensitive High-Performance Liquid Chromatographic method has been developed for the simultaneous determination of Ramipril (RMP) and Hydrochlorothiazide (HCT) in bulk drug and in tablets. Ramipril (RMP) and Hydrochlorothiazide (HCT) were eluted from an Eclipse plus C18 (250 mm × 4.6 mm I.D.) with particle size 5 µm reversed phase column with a mobile phase consisting of acetonitrile and potassium dihydrogen ortho-phosphate pH 3 (40: 60 v/v) at a flow rate of 1 mL/min with UV detection at 210 nm. The retention time for RMP and HCT was found to be 3.31 ± 0.02 min and 6.64 ± 0.02 min, respectively. The linear response (r2 <0.99) was observed in the range of 2 - 12 μg/mL for RMP and 4 - 24 μg/mL of HCT with low values of limits of detection (LOD) and quantification (LOQ) for both drugs. The method shows good recoveries and intra and inter-day relative standard deviations were less than 1.0%. Validation parameters as specificity, accuracy, ruggedness and robustness were also determined. The proposed method provides accurate and precise quality control tool for routine simultaneous analysis of Ramipril and Hydrochlorothiazide in bulk and in tablet dosage form.

Pharmacokinetics and tissue distribution of LN002, a new compound alternative oxidase inhibitor against Cryptosporidium in rats.

Cryptosporidiosis is considered a crucial zoonotic disease caused by widely distributing parasitic protozoa called Cryptosporidium spp. Nitazoxanide is the only FDA-approved drug but is only effective with a good immune response of the host. In addressing this unmet medical need, we previously identified a compound, namely, LN002, as a potent alternative oxidase inhibitor against cryptosporidiosis. To illustrate the pharmacokinetics, absolute bioavailability, and tissue distribution of LN002 in rats, rapid and sensitive high-performance liquid chromatography was developed and validated for the separation and detection of LN002 in plasma, tissue samples, and intestinal contents. In this study, a single dose of oral administration and intravenous injection of LN002 was used to determine the levels of LN002 in plasma, tissue samples, and intestinal contents by UHLC. Results of the study indicated that after intravenous administration of 1mg/kg LN002, the AUC0-24 h, T1/2,Vd, and Cl were 7024.86h·ng/mL, 10.91h, 1.69L/kg, and 0.11L/h/kg, respectively. After oral administration of a single dosage of 100, 200, and 400mg/kg LN002, the Tmax, Cmax, AUC0-24h, T1/2, F, Vd, and Cl/F in plasma of rats were 1h, 849.88-4033.21ng/mL, 2280.41-7498.10h·ng/mL, 17.96-18.83h, 0.27%-0.32%, 581.54-869.21L/kg, and 25.97-39.00L/h/kg, respectively. After oral administration of 200mg/kg, LN002 was extensively distributed in the main tissues of rats, and massive amounts of LN002 were distributed in the intestine and intestinal contents, indicating its potential as an effective anti-Cryptosporidium compound. After oral administration of a single dosage of 200mg/kg, LN002 has a low bioavailability and high levels in the intestine, which is crucial for the safe and effective treatment of cryptosporidiosis. Overall, the results of this study provide valuable data support for the future study of LN002.

A simple and sensitive high-performance liquid chromatographic method combined with fluorescence detection for bioanalysis of scopoletin in rat plasma: Application to a pharmacokinetic study.

Scopoletin, a coumarin class natural phytoalexin, is present in medicinal plants such as noni (Morinda citrifolia). It exhibits diverse pharmacological properties, including antioxidant, anti-hyperuricemic, and anti-inflammatory effects. The objective of this study was to develop a novel HPLC-fluorescence (HPLC-FL) method for the quantitative analysis of scopoletin in the plasma and to investigate its pharmacokinetics in rats. Sample preparation involved a methanol-based protein precipitation method, and chromatographic separation was conducted using a C18 column with an isocratic mobile phase composed of water and acetonitrile containing 0.1% trifluoroacetic acid. The eluent was detected using an FL detector set to optimized excitation/emission wavelengths of 337/453 nm. Method validation encompassed assessments of selectivity, linearity (1-500 ng/mL), precision, accuracy, recovery, matrix effect, and stability in accordance with the prevailing Food and Drug Administration (FDA) guidelines. The developed method was successfully applied for pharmacokineticstudy in rats. To the best of our knowledge, this study is the first application of a simple and sensitive HPLC-FL method for the quantification of scopoletin in a pharmacokinetic study. This method offers a promising alternative for preclinical pharmacokinetic investigations with appropriate modifications and validations and holds potential for clinical applications.

Quantitation of Key Antioxidants and Their Contribution to the Oxidative Stability of Beer.

A sensitive high-performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-MS/MSMRM) method, leveraging both technique and internal calibration, was developed for the simultaneous and comprehensive quantitative analysis of 46 antioxidants and antioxidant precursors in different beer types without any cleanup procedure. Combined with their in vitro antioxidant activity, a dose-activity estimation exposed a group of 10 key antioxidants, namely, tryptophan, tyrosine, hordatine A, hordatine B, procyanidin B3, prodelphinidin B3, tachioside (3-methoxy-4-hydroxyphenyl-β-d-glucopyranoside), (+)-catechin, tyrosol, and ferulic acid. To study the effect of antioxidants in spiking and aging studies, another liquid chromatography-MS (LC-MS)-based method was developed, monitoring markers for oxidation in beer. A positive effect of the antioxidants on the flavor stability at naturally relevant concentrations was shown by a slowing of oxygen-dependent aging reactions highlighted in beer storage trials under oxygen atmosphere. Thereby, a doubling of the natural concentration of all investigated antioxidants in beer revealed a limit inhibition of 67% on the degradation of cis-isocohumulone to hydroxy-cis-alloisocohumulone.

Determination of Veratrum alkaloid contents in three Veratrum species by HPLC-MS/MS.

Veratrum alkaloids have gained attention due to their toxic effects and potential pharmaceutical applications, particularly in cancer and cardiology. Over 200 alkaloids are found in species of the Veratrum genus. The alkaloid composition and concentrations can greatly vary in plants depending on factors like species, plant part, location, season, weather, or nutrients. This study aims an analytical approach to analyze and quantify Veratrum alkaloids in different plant parts of Veratrum species. The purpose is to contribute essential alkaloid concentration data for future research on the pharmacological and toxicological aspects of Veratrum alkaloids. This study focuses on five Veratrum alkaloids (cevadine, jervine, protoveratrine A, veratramine, and veratridine) in three Veratrum species (Veratrum album L., Veratrum californicum Durand, and Veratrum nigrum L.) collected from four German botanical gardens (Dresden, Leipzig, Marburg, and Schellerhau). A liquid-liquid extraction method and a sensitive high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) method operating in multiple reaction monitoring (MRM) mode were applied for the alkaloid determination. Quantification revealed varying alkaloid concentrations among plant parts and Veratrum species in the μg/g to mg/g range. Protoveratrine A exhibited the highest content, while veratramine concentrations were generally lower. Especially in fruit, roots and rootstock of Veratrum album L. alkaloid concentrations were significant high. The developed HPLC-MS/MS method successfully determined Veratrum alkaloid concentrations in plant samples. The study contributes valuable data on Veratrum alkaloid distribution in different species and plant parts, crucial for understanding their potential medicinal and toxicological significance.

Single Method for Determination of Biocides Benzalkonium Chloride, Chloroxylenol and Chlorhexidine Gluconate in Cosmetics, Hygiene and Health Care Products by Using High Performance Liquid Chromatography.

Benzalkonium chloride (BKC), chloroxylenol (PCMX) and chlorhexidine gluconate (CHG) are widely recognized biocidal compounds that require precise control and monitoring in various applications, including cosmetics, hygiene, health and ophthalmic products. In this study, we present a straightforward and highly sensitive high-performance liquid chromatographic (HPLC) method for the detection of these substances. The HPLC method we developed allows for the detection of BKC at concentrations as low as 1.0ppm, PCMX at 1.0ppm and CHG at 2.0ppm, all with a signal-to-noise (S/N) ratio exceeding 3.0. Additionally, the method enables quantification up to 2.0ppm for BKC, 2.0ppm for PCMX and 5ppm for CHG, with an S/N ratio surpassing 10.0. This validated method serves as a versatile tool for the accurate quantification of BKC, PCMX and CHG in cosmetics, hygiene products, health products and ophthalmic products. Its applicability extends across a wide range of industries, ensuring the reliable assessment of these critical biocides.

Response surface experimental design for simultaneous chromatographic determination of two antiviral agents “Favipiravir and Remdesivir” in pharmaceuticals and spiked plasma samples

AbstractThe antiviral agents, Favipiravir (FAV) and Remdesivir (REM), were introduced in the last few years alone or as combination regimen for successful management of the rapidly spreading CORONA virus pandemic. A newly developed rapid and sensitive high performance liquid chromatographic method (HPLC) has been developed for the simultaneous determination of their mixture. Firstly, one factor at a time optimization (OFAT) has been applied. Afterwards, quality by design approach (QbD) has been utilized using Box Behnken experimental design (BBD) for the development of an experimental design of four independent and nine dependent variables for much better refining of the optimized parameters. The established model has given an optimum resolution at; acetonitrile percentage of 52.66, mobile phase of pH 2.91, percentage of triethylamine of 0.15 and 1.30 mL/min flow rate. The proposed method has been validated according to the USP 31 NF 26 guidelines. Good linearity ranges have been obtained from 5.00 up to 50.00 μg/mL for FAV and from 2.00 up to 60.00 μg/mL for FAV and REM, respectively. Excellent relative standard deviation values (not more than 1.40) were obtained upon investigation of accuracy, precision and robustness. The developed method has succeeded in analysis of investigated drugs in their pharmaceutical formulations and spiked plasma samples with good recoveries of 99.00 and up to 106.00%. The proposed method is considered eligible for the quality control laboratories as well as in‐vivo determinations of both analytes.

Analysis of the Influence of Different Processing Methods on the Main Effective Components in Oviductus Ranae by High-Performance Liquid Chromatography with Diode Array Detector

Oviductus Ranae (OR) is one of the “treasures of Changbai Mountain” in China. It is used clinically for the treatment of infirmity after illness, fatigued spirit, cough, hemoptysis, and so forth. In this study, a simple and sensitive high-performance liquid chromatography-diode array detector (HPLC-DAD) method was developed for the simultaneous determination of five main effective components (1-methyl hydantoin, estradiol, cholesterol, 7-keto-cholesterol, and 4-cholesten-3-one) in OR and its different processed products. The results indicated that these five components showed good linear relationships within their own concentration ranges along with coefficients of determination ≥0.9996. Average recoveries ranged from 97.67% to 100.06%, with RSDs of 1.45%–1.99%. The proposed method was found to be simple, accurate, and stable, which provided an effective analytical method for quality control and evaluation of OR and its different processed products.

Characterization of Forced Degradation Products of Netarsudil: Optimization and Validation of a Stability-Indicating RP-HPLC Method for Simultaneous Quantification of Process-Related Impurities.

The aim of this study is to examine resolution, identification, and characterization of forced degradation products of netarsudil by liquid chromatography-tandem mass spectrometry by validating a simple and sensitive high-performance liquid chromatography method for the resolution, identification, and quantification of two process-related impurities in netarsudil. Chromatographic separation was accomplished on a ZORBAX Eclipse XDB C18 (250 x 4.6 mm; 5 µ id) column at room temperature as the stationary phase and 257 nm as the detector wavelength with the mobile phase consisting of acetonitrile, methanol, and pH 4.6 phosphate buffer in 45:35:20 (v/v) at 1.0 mL/min flow rate in isocratic elution. The method reported very sensitive detection limits of 0.008 µg/mL for impurity 1 and 0.003 µg/mL for impurity 1. The method produces a calibration curve linear in the concentration level of 25-200 for netarsudil and 0.025-0.2 µg/mL for impurities. The proposed method gives acceptable results for other validation parameters such as accuracy, precision, ruggedness, and robustness. The drug was subjected to various stress conditions such as acid, base, peroxide, and thermal and ultraviolet light to investigate the stability-indicating ability of the method. Considerable degradation was observed in stress studies, and the degradation products were well resolved from process-related impurities. The characterization of degradation products was performed on the basis of collision-induced dissociation mass spectral data, and the possible structures of the six degradation compounds of netarsudil were proposed. The outcomes of other validation studies were likewise satisfactory and proven adequate for the regular analysis of netarsudil and its process-related impurities in bulk drug and pharmaceutical dosage forms and can also be applied for the evaluation of the stress degradation mechanism of netarsudil.

Simultaneous Determination of Two Metabolites of Gelsemium elegans by LC-MS/MS in Rat Urine and its Application to Pharmacokinetic Study

Background: G. elegans is a highly useful medicinal plant with broad and superior clinical pharmacological effects. However, it also exhibits high toxicity to humans, so it must be used with extreme caution in clinical practice. Previous studies on G. elegans have mainly focused on its main ingredients from perspectives of pharmaceutical analysis, pharmacokinetics, and pharmacodynamics. The kinetic behavior of G. elegans' main metabolites in vivo has not yet been reported, which is also crucial for studying the herb's toxification and detoxification process. Aims: This study aimed to establish a quantitative method to describe the metabolic profile of the two main metabolites of koumine after oral administration of G. elegans to rats. Objective: The objective of this study was to test two major metabolites of G. elegans in rat urine after administration using a rapid and sensitive high-performance liquid chromatographic-tandem mass spectrometric (HPLC-MS/MS) method developed in advance. Methods: A Kromasil C18 column was used as the stationary phase for chromatographic separation, with an isocratic mobile phase consisting of mixture of water (2 mM ammonium formate), formic acid, and methanol (25:0.05:75, v/v/v) at a flow rate of 0.40 mL/min. The mass spectrometer was equipped with an electrospray ionization (ESI) source operating in positive ionization mode, and detection was performed using a selective reaction monitoring (SRM) mode. Detection was performed in selective reaction monitoring (SRM) mode. Protein precipitation was used to pretreat the rat urine samples before analysis, with acetonitrile as the precipitation solvent. In this study, a "relative quantification" strategy was employed, which avoided the expensive and time-consuming separation of standard substances. The assay was validated in terms of specificity, linearity, precision, stability, recovery, and other aspects. Results: The intra- and inter-day precision values were less than 12.7%. The recoveries at three different concentrations were all above 73.1%. The stability study showed that the analytes were stable during the experiment. The method was then used to study the kinetic profiles of N-demethylkoumine and N-oxidatekoumine in rat urine for the first time. Conclusion: In this study, the established LC/MS method was fully validated and proven to be sensitive and accurate for the simultaneous determination of the two main metabolites of G. elegans in rats' urine samples. These results could provide references for the safe use of koumine and G. elegans in clinical applications.

Quantification of nine bufadienolides of Shexiang Tongxin Dropping Pills in rat plasma and tissues using UPLC-MS/MS and its application to healthy and ischemia-reperfusion rats pharmacokinetic studies

Shexiang Tongxin Dropping Pill (STDP) is a well-known compound preparation used in traditional Chinese medicine for treating cardiovascular diseases. Bufadienolides are the major active compounds of toad venom and are the key to the seven medicinal herbs that comprise STDP. In this study, a reliable and sensitive high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the quantitative determination of nine bufadienolides (bufalin, gamabufotalin, resibufogenin, marinobufagin, arenobufagin, desacetylcinobufagin, telocinobufagin, hellebrigenin, and hellebrigenol) in rat plasma and tissues (heart and liver). The chromatography column used was a Waters ACQUITY UPLC HSS-T3 column with gradient elution using mobile phase consisting of acetonitrile–water (0.1% formic acid added) at a flow rate of 0.25 mL/min. This method passed the methodological validation of plasma and tissues and was successfully applied to pharmacokinetic and tissue distribution studies after oral administration of STDP in healthy and ischemia-reperfusion (I/R) rats. This indicated that most bufadienolides were well absorbed and quickly distributed in the heart and liver. The area-under-the-curve (AUC)(0−t) of most analytes increased in a dose-dependent manner. Moreover, most of the tested components showed lower plasma and higher tissue concentrations in I/R rats than in healthy rats. The above results on the oral pharmacokinetics and tissue distribution may be helpful for the clinical application of STDP.

Investigating a Simple and Sensitive High-performance Liquid Chromatography Method for Simultaneous Determination of Apigenin, Catalpol, and Gallic Acid Contents in Plantago Lanceolata L. and Plantago Major L.

Investigating a Simple and Sensitive High-performance Liquid Chromatography Method for Simultaneous Determination of Apigenin, Catalpol, and Gallic Acid Contents in Plantago Lanceolata L. and Plantago Major L.

Highly selective and sensitive high performance liquid chromatography method for determination of fumonisins from feed samples with MIL-101 based dispersed micro-solid-phase extraction and precolumn fluorescence derivatization

A selective and rapid high-performance liquid chromatography with fluorescence detection (HPLC-FLD) method for determining fumonisins was established and validated, which based on dispersed microsolid-phase extraction (D-μ-SPE) and precolumn derivatization. The MIL-101 was prepared as sorbents to selectively enrich two fumonisins from feed samples. The obtained extracts were labeled by a novel derivatization reagent 2,5-dioxopyrrolidin-1-yl 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoate (MPIBA-Su). There was no fluorescence from fumonisins itself, while their derivatives exhibited considerable fluorescence with a maximum excitation at λex 255 nm and a maximum emission at λem 457 nm. Key factors affecting extraction efficiency and derivatization efficiency were fully optimized. Excellent linearity was achieved with correlation coefficients > 0.9935 under optimal conditions. The detection limits (LODs) were between 2.4 and 3.5 ng·mL−1, and the quantitation limits (LOQs) were between 8.1 and 11.7 ng·mL−1. With recoveries in the range of 83.8% − 94.3%, the established method has successfully been applied to the quantitative analysis of fumonisins in feed samples.

Rapid Determination of Lignans in Schisandra chinensis by Supramolecular Solvent (SUPRAS)-Based Extraction and High-Performance Liquid Chromatography–Tandem Mass Spectrometry (HPLC-MS)

A supramolecular solvent (SUPRAS)-based sample preparation method was proposed for the determination of lignans in Schisandra chinensis (S. chinensis) fruit. The optimal conditions were: proportion of hexafluoroisopropanol in SUPRAS: 35% (v/v), solid-to-liquid ratio: 20:1 mg/mL, and vortex time: 30 s. Additionally, simple, rapid, and sensitive high-performance liquid chromatography coupled with triple quadrupole mass spectrometry and multiple reaction monitoring was employed to simultaneously quantify seven lignans in S. chinensis. The validation showed that the linearity from 0.01 to 20.83 µg/mL was excellent (all R 2 ≥ 0.99). The lowest limits of quantification were from 0.14 to 17.79 ng/mL. The relative standard deviation (RSD) of the intra-day retention time and peak area were from 0.12% to 0.21% and 2.35% to 6.41%. The RSD of retention time and peak area for the inter-day precision ranged from 0.17% to 0.32% and 3.83% to 7.39%. The average recoveries (80.21%–114.53%) demonstrated good accuracy for all analytes. The developed procedure was employed to determine lignans in processed and raw S. chinensis fruit. The lignans were concentrated in the seeds and the wine-processed material had the highest content. This study provides a reference for the analysis of S. chinensis fruit for lignans.

Development of Simultaneous Determination Method of Pesticide High Toxic Metabolite 3,4-Dichloroaniline and 3,5 Dichloroaniline in Chives Using HPLC-MS/MS.

3,4-dichloroaniline (3,4-DCA) and 3,5-dichloroaniline (3,5-DCA) are, respectively, the primary metabolites deriving from the breakdown of phenylurea herbicides and dicarboximide fungicides in both soils and plants, whose residues in vegetable products have a heightened concern considering their higher health risks to humans and greater toxicity than the parent compounds in the environment. In this study, a sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the simultaneous determination of 3,4-DCA and 3,5-DCA residues in chive products based on the optimization of HPLC-MS/MS chromatographic and mass-spectrometric conditions using the standard substances and the modified QuEChERS preparation technique. The preparation efficiency of 3,4-DCA and 3,5-DCA from chive samples showed that acetonitrile was the best extractant. The combination of the purification agent graphite carbon black + primary secondary amine and the eluting agent acetonitrile + toluene (4:1, v/v) had a satisfactory purification effect. The linear correlation coefficients (R2) were more than 0.996 with the six concentration range of 0.001-1.000 mg/L for 3,4-DCA and 3,5-DCA. The limit of detection and limit of quantitation of this method was 0.6 and 2.0 µg/kg for 3,4-DCA, as well as 1.0 and 3.0 µg/kg for 3,5-DCA, respectively. The matrix effect range of 3,4-DCA and 3,5-DCA in chive tissues was from -9.0% to -2.6% and from -4.4% to 2.3%, respectively. The fortified recovery of 3,4-DCA and 3,5-DCA in chive samples at four spiked levels of 0.001-1.000 mg/kg was 75.3-86.0% and 78.2-98.1%, with the relative standard deviation of 2.1-8.5% and 1.4-11.9%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.6, 2.0, and 1.0, 3.03 for 4-DCA and 3,5-DCA, respectively. This study highlights that the analytical method established here can efficiently and sensitively detect residues of 3,4-DCA and 3,5-DCA residues for monitoring chive products. The method was successfully applied to 60 batches of actual vegetable samples from different regions.

Development of HPLC-DAD method for the quantification of pentostatin in the fruiting body of Cordyceps militaris

Cordyceps militaris is an important medicinal mushroom in traditional medicine. It contains many bioactive compounds that have applications in medicine, such as cordycepin, adenosine... Recently, through genome analysis, C. militaris has been shown to have the ability to synthesise pentostatin. Pentostatin is an important active ingredient in the production of chemotherapy drugs used in cancer treatment. However, there have been few studies on the development of methods for quantifying pentostatin in C. militaris. In this study, a simple and sensitive high-performance liquid chromatography with diode-array detection (HPLC-DAD) method for the quantification of pentostatin in C. militaris was developed and validated. The chromatographic separations were obtained by an Agilent C18 column (250x4.6 mm i.d., 5 μm particle size) using gradient elution with acetonitrile and water. The flow rate of 0.6 ml/min and detection wavelength of 280 nm were selected. The calibration curve displayed a good linear correlation (R2>0.99). The validation results displayed great accuracy, repeatability, linearity, and selectivity according to The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guideline.

Development of HPLC-UV Method for Simultaneous Determination of Corticosteroid Co-Administered Immune Therapy.

Prednisolone (PDS) has recently been utilized to treat a variety of medical disorders, including autoimmune illnesses and cancer. It is also used to treat coronavirus disease 2019 infection-related respiratory problems. Because it may induce health problems including gastrointestinal lesions and ulceration, it has to be used alongside other drugs like esomeprazole (ESM), which acts as a proton pump antagonist to reduce the probability of ulceration. As a result, the goal of this research is to create an environmentally safe and sensitive high-performance liquid chromatography (HPLC) approach for determining PDS and ESM in their binary combination and spiked human plasma. C8 column (100 × 4.6mm, 5μm) and gradient mobile phase elution were used to separate the studied drugs with ultraviolet recognition at 290nm. Caffeine was utilized as an internal standard to adjust the sample variance. Plasma, caffeine, ESM and PDS all had tR values of 1.4, 3.5, 6.3 and 7.3, respectively. The suggested method's greenness features were evaluated using three greenness evaluation tools: green analytical procedure index, analytical greenness metric approach and analytical eco-scale, and the findings were approved and satisfied. Validation parameters were evaluated in accordance with US-FDA recommendations in order to meet the global desires for biological analysis technique, acceptable limits were obtained.

Application of solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) and comparison of both detection techniques (DAD and FLD) to analyse nesfatin-1 in fetal bovine serum samples

AbstractIn this study, we propose a simple, cost-effective, and sensitive high-performance liquid chromatography with both detection techniques such as diode-array detection and fluorescence detection (HPLC-DAD-FLD) for the determination of nesfatin-1 in fetal bovine serum samples. The limit of detection (LOD) and limit of quantification (LOQ) for nesfatin-1 were set at satisfactory values in the range 0.22–0.35 mg mL−1 and in the range 0.67–1.05 mg mL−1, respectively (at two different wavelengths (DAD) and at four different wavelengths (FLD)). Analyte concentrations were determined as the average value from fetal bovine serum matrix samples. The preliminary results show that the SPE procedure on Isolute Si-TsOH (SCX-3) could be used for further nesfatin-1 analyses in human serum samples. Both the SPE technique, chromatographic analysis with gradient elution mode and detection technique are fast and convenient.