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A novel simple and cost effective HPLC technique was presented for the quantification of selexipag (SLP) in human plasma sample and the technique's applicability to a pharmacokinetic investigation. Chromatographic separation was achieved with C18 (5 µm × 4.6 mm × 150 mm) column, at 30 °C with isocratic elution, mobile phase composed of solution A (acetonitrile), and solution B (0.5% formic acid) (65:35 v/v) at flow rate 1.2 mL min−1. The linearity range is 10–150 ng mL−1. As sample preparation step human plasma was precipitated with acetonitrile and the detection was provided at 300 nm. The retention time is 8.20 ± 0.02 min. LOD is found to be 3.3 ng mL−1 for drug. The method was applied to the analysis of SLP in human plasma with good recovery as 97.83%. Validation of the studied methods was carried out according to EMA guideline. The new method applied on a prototype pharmacokinetic study by administration of 800 μg SLP to a healthy volunteer and parameters like AUC0–24, AUC0–∞, Cmax, tmax, and t1/2 were assessed. [ABSTRACT FROM AUTHOR]

In this study, the analytical and developed method was successfully validated for the simultaneous determination of benzoic acid (BA) and Sorbic acid (SA) by natural deep eutectic solvent (DES) composed of thymol/water and dispersive liquid–liquid microextraction (DLLME) followed by HPLC/UV in orange juice samples. A response surface methodology (RSM) based on a central composite design (CCD) was applied for optimization of the main variables. The significant parameters including DES volume (600 µL), dispersive solvent volume (THF) (709 µL), sample volume (11.1 mL), salt amount (5% w/v), and vortex time (10 min) were optimized. Under the optimal conditions, the limits of detection (LOD) and limits of quantifications (LOQ) were obtained 0.468 and 1.419 mg L−1 for BA and 2.517 and 7.628 mg L−1 for SA, respectively. The recovery values were between 94 and 97%. R2 of BA and SA were 0.9940 and 0.9921, respectively. [ABSTRACT FROM AUTHOR]

An amide‐based covalent organic framework (COF) was successfully synthesized using the reaction between 1,3,5‐trimesoyl chloride and ethylenediamine. The structure and morphology of the COF were characterized using Fourier‐transform infrared spectra, nuclear magnetic resonance spectroscopy, X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and Brunauer‐Emmett‐Teller surface area analysis. The COF was employed as a solid‐phase extraction adsorbent for the sampling and preconcentration of chlorophenols from industrial wastewater samples prior to high‐performance liquid chromatography with ultraviolet detection. The experimental parameters influencing the extraction efficiency including type and volume of eluent solvent, sample solution volume, salt concentration, sample flow rate, and sample solution pH were investigated and optimized using a response surface methodology employing Box‐Behnken‐design. Under optimized conditions, calibration curves exhibited good linearities over the range of 0.003–10 µg/mL with determination coefficients (R2) ranging from 0.9982 to 0.9999. The method's limits of detection ranged from 0.001 to 0.01 µg/mL. Good repeatability was achieved with relative standard deviations below 4.7%. The developed procedure utilizing the COF adsorbent was successfully applied to determine chlorophenols accurately and precisely in various industrial wastewater samples. [ABSTRACT FROM AUTHOR]

Flavonoids are a prominent group of plant phenolics (polyphenol group) extensively present in the human diet and associated with health promotion. Flavonoids are essential in various pharmaceutical, nutraceutical, and cosmetic applications. To collect and categorize these compounds, we comprehensively assessed High-performance liquid chromatography (HPLC) techniques published to analyze flavonoids in various matrices. Most documented methods employed liquid chromatography with ultraviolet detection (HPLC-UV) and tandem mass spectrometry (LC-MS/MS) methods. Among chromatographic techniques, reversed-phase liquid chromatography remains the predominant and efficient method for separating various analytes. This review explores the primary chromatographic methods used to separate and quantify flavonoids in herbs, fruits, and biological samples. This article examines recent literature on applying liquid chromatography with different detection methods for analyzing flavonoids. To examine recent literature on applying liquid chromatography with different detection methods for analyzing flavonoids. It offers valuable insights to researchers as they prepare to develop quantification methods. [ABSTRACT FROM AUTHOR]

Each year, new psychoactive substances appear on the global drug market leading to constant changes. Most of these compounds with stimulating effect possess a chiral center, thus leading to two enantiomers with presumably different pharmacological properties. Among them, synthetic cathinones, often misleadingly traded as "bath salts," play an important role. There is little knowledge about the distinct effect of the enantiomers. The aim of this study was to test a commercially available Lux® i‐Amylose‐3 column by HPLC‐UV for enantiorecognition of cathinone derivatives. Overall, 80 compounds were tested in normal phase mode, where 75 substances were separated under initial conditions. After method optimization, at least partial separation was achieved for the remaining compounds. The same set of substances was measured in polar‐organic mode, where 63 analytes were resolved into their enantiomers under initial conditions with very short retention times. Both modes showed complementary results for the individual compounds. Furthermore, the tested methods proved to be suitable for differentiation of positional isomers, which can be useful for drug checking programs. All measurements were carried out under isocratic conditions, and intraday and interday repeatability tests were performed. [ABSTRACT FROM AUTHOR]

In this study, phenolic acid compositions in fourteen taxa of Boraginaceae were analyzed by HPLC-UV to obtain informative chromatographic data. In general, 9 phenolic acid compounds were identified in different studied taxa. m-coumaric acid (1.80-1962.09 mg/kg), salicylic acid (13.22-867.35 mg/kg), ferulic acid (0.00-661.69 mg/kg), and pcoumaric acid (12.10-392.48 mg/kg) were characterized as the main compounds of the studied taxa. The results indicated that m-coumaric acid was the main phenolic acid in Heterocaryum rigidium, Myosotis sylvatica, and Solenanthus stamineus. Furthermore, salicylic acid was the main phenolic acids of Myosotis sylvatica and Nonnea caspica. Also, the highest amounts of ferulic acid and p-coumaric acid were detected in Myosotis sylvatica and Heliotropium europaeum, respectively. The qualitative and quantitative evaluation of these compounds was used for the characterization of the taxa and for revealing their phytochemical similarity and differentiation. Hierarchical cluster analysis showed that the studied taxa were classified into two main clusters (I and II) based on main phenolic acid compounds. Cluster I included Heterocaryum rigidum, Solenanthu stamineus, and Lappula microcarpaa, and the rest studied taxa grouped in cluster II. The chemotaxonomic significance of the isolated compounds was discussed. [ABSTRACT FROM AUTHOR]

A technique for quantitative determination of biapenem in human blood plasma using HPLC with UV detection was developed to provide therapeutic drug monitoring in a hospital setting. Detection was made spectrophotometrically at 300 nm. The chromatographic procedure lasted 15 min. Precipitation with MeCN was used for sample preparation. The lower limit of quantification was 0.2 μg/mL. The methodology was validated for the main parameters. Linearity was observed over a wide concentration range from 0.5 to 100 μg/mL. The results made it possible to use the developed method for rapid determination of the biapenem content in patient blood plasma, which enabled personalization of the drug doses and increased the efficiency and rationality of antibacterial therapy. [ABSTRACT FROM AUTHOR]

Owing to ergosterol content, after UV irradiation yeast become a well-known source of ergocalciferol (vitamin D2). Additionally, pharmaceutical yeast-based supplements may represent a suitable option for treating hypovitaminosis, especially in patients adhering to a vegan diet. Using the high-performance liquid chromatographyultraviolet (HPLC-UV) methodology our study sought to analyse three commercially available yeast-based vitamin D2 supplements while comparing the effect of UV-C irradiation (254 nm) on yeast biomass derived from the brewing process and pure ergosterol. The two compounds were precisely separated under the described conditions in an efficient and quick manner with a retention time (Rt) of 4.152 ± 0.018 minutes for vitamin D2 and 5.097 ± 0.013 minutes for ergosterol. However, when approaching the quantitative analysis, based on our findings, it appears that the pharmaceutical supplements deviate from the declared amount of substance indicated on the label. 15 minutes of UVC irradiation generates vitamin D2 in yeast biomass with a conversion rate of 1.78%. Also, high content of ergosterol, beside vitamin D2 formation after irradiation, may trigger the appearance of secondary products such as tachysterol. [ABSTRACT FROM AUTHOR]

Monosodium glutamate is a food additive that gives sweetness, sourness, bitterness, and saltiness tastes together. In the present study, a simple and accurate high-performance liquid chromatography with ultraviolet spectrophotometer detector method was developed for the determination of monosodium glutamate in both dried and moist food samples. This method was carried out on different eleven food samples including potato chips, soups, and vegetable concentrates from the local market in Jordan. The approach was based on the derivatization step of MSG with 1-fluoro-2,4-dinitrobenzene. A good chromatographic separation is obtained by using a 5-micro meter particle size octadecyl column and one-to-one methanol: water mixture as mobile phase. The results in the calibration curve were linear with a correlation coefficient R2 was 0.9533. The tested food samples contained various MSG contents (the highest content was in the Mexicana chips sample 353 ± 7 ppm). The contents of monosodium glutamate in most investigated food samples were between 170 and 350 ppm. These contents are allowed according to the general standards of the codex Alimentarius Commission for food additives. [ABSTRACT FROM AUTHOR]

COVID-19 is a serious virus that can have a lot of effects, one of which is a secondary bacterial infection that can be more life-threatening and even lethal than the initial viral infection. Hence a fast and sensitive HPLC/UV method was developed and validated for the first estimation of a binary mixture of molnupiravir (MOL) and ertapenem (ERT) as a co-administrated medicine for the management of COVID-19 in pharmaceutical dosage forms, and human plasma samples. The drug combination was separated within 5 min via RP-ODS column using isocratic elution with a mobile phase of 0.05 M phosphate buffer (pH 3.5): acetonitrile with a 76: 24% ratio v/v. The presented method provided a linear response ranging from 0.03 to 17.0 and 0.05–20 µg mL−1 with LOD values of 0.009 and 0.008 µg mL−1 for MOL and ERT respectively. The good separation and high sensitivity of the HPLC method provide the determination of the cited drugs in human plasma without matrix interference with a percent of recovery ranging from 94.97 ± 2.05 to 98.44 ± 1.92. Based on the results, this method could be utilized to monitor cited drugs in quality control and therapeutic laboratories. [ABSTRACT FROM AUTHOR]

Efonidipine hydrochloride ethanolate (EFE), a dihydropyridine calcium channel blocker, is used for the treatment of hypertension. To find the EFE in pre-clinical samples (rat plasma), an HPLC method was devised for the current experiment. The biological samples were prepared using the methanolic extraction procedure to eliminate solvent effects. Using a C18 column, a pH-adjusted mobile phase of methanol and water (90:10, v/v) at a flow rate of 1 mL/min, and UV detection at 252 nm were utilized for chromatographic separation. The retention time of EFE was found to be 5.2 min. The developed bioanalytical method was validated with different validation parameters. The validation parameter results are within the acceptable range of the International Council for Harmonization guidelines. The method was successfully employed to evaluate the pharmacokinetic properties in Wistar albino rats following a single oral administration of 10 mg/kg of EFE. Therefore, the simple method would make it possible to detect EFE quickly and affordably from biological material. [ABSTRACT FROM AUTHOR]

Amount of α-escin and β-escin in cosmetic cream formulations were determined by simple reverse phase HPLC method by using the C18 column at 220 nm. The mobile phase is composed of acetonitrile-water (60:40) at pH 2.4. The method validation study was carried out based on the ICH recommendations and linear regression equations were determined as y=1548.3x+340.7 and y=1521.3x-91.9, for the analytes, respectively. While LOD values of the method were determined for α-escin and β-escin as 0.003 μg/mL and 0.027 μg/mL, LOQ values were determined as 0.01 μg/mL and 0.08 μg/mL, respectively. [ABSTRACT FROM AUTHOR]

The method for simultaneous determination of the two types of principal components, C21- steroids and acetophenones, in Cynanchum bungei, C. auriculatum and C. wilfordii by high-performance liquid chromatography-ultraviolet (HPLC-UV) was developed for the first time. Under the optimized conditions, good linearities (R2 ≥ 0.999) were obtained for all analytes, and relative standard deviations (RSDs) of HPLC-UV method validation ranged from 0.01-1.62%. The results of DPPH (1,1-diphenyl 2-picryl hydrazyl) and ABTS (2,2-azobis-3ethylbenzthiazoline-6-sulfonic acid) free radical scavenging assays indicated that the three species had a significant antioxidant activity, with the half maximal effective concentration (EC50) range of 64.56-593.38 μg/mL. Combined with bivariate analysis, the fingerprintactivity relationship of the offline antioxidant activity of the three species with their fingerprints peak was studied, and the results revealed a dose-effect relationship between acetophenones and antioxidant activity. This study provides a theoretical basis for the correct identification and application of the antioxidant activities of C. auriculatum, C. wilfordii and C. bungei. [ABSTRACT FROM AUTHOR]

The present study was to develop and validate a rapid analytical method of high-performance liquid chromatography with UV (HPLC-UV) detection for the determination of levetiracetam (LEV) concentration in human serum and cerebrospinal fluid (CSF) samples. The newly developed method was used to measure LEV concentration in the serum/CSF of 29 patients with different types of epilepsy; 52% (group I, n = 15) were treated with LEV in monotherapy, 48% (group II, n = 14) were co-administered with other antiseizure medications (ASMs). Serum and CSF levels of LEV were correlated with patients' dosage, concomitant ASMs, therapeutic effects, and adverse drug reactions (ADRs). The calibration curves for serum and CSF were linear in the range of 0.5-100 and 0.5-50 mg/L, respectively, with a coefficient correlation (R) value > 0.998 in each case. The quantitation limit was 0.5 mg/L in serum and CSF. The validated method was found to be selective, precise, and accurate. Optimal Css min values according to International League Against Epilepsy (12-46 mg/L) were achieved in 40 and 50% of patients in groups I and II and did not correlate with treatment efficacy in 27 and 21% of patients, respectively. The ratio of serum LEV to CSF concentration (Kp) after 2 h administration LEV ranged in group I from 0.31 to 0.92 and in group II from 0.18 to 0.65. These findings indicate that the developed simple and rapid HPLC-UV method may be useful for monitoring serum/CSF LEV concentrations in patients receiving standard doses. [ABSTRACT FROM AUTHOR]

Objectives: To develop and validate a modified HPLC-UV method for the estimation of serum levetiracetam levels and to assess the usefulness of serum levetiracetam estimation in epileptic patients. Materials and Methods: Modification of a previously existing HPLC-UV method was performed using liquid-liquid phase extraction and processing using reverse phase analytic HPLC-UV detector technique followed by method validation. Serum samples of patients attending our hospital's Therapeutic Drug Monitoring Outpatient Department services were analyzed for levetiracetam levels using the study method. Data of the past 6 years (2015-2020) were descriptively analyzed. Results: The modified HPLC-UV method was validated as per ICH Q2 (R1) 2005 guidelines. Usefulness of levetiracetam estimation was assessed in 1383 patients (635 children, 683 adults, 40 elderly, and 25 pregnant women). Levetiracetam levels were within the therapeutic range (TR) in 520 children, 543 young adults, 35 elderly patients, and nine pregnant women. In 112 of 232 patients with low levetiracetam levels, poor compliance was elicited. Of 641 patients on polytherapy, 446 patients had levetiracetam values within TR, whereas 29 had values above and 166 patients had values less than TR. Sodium valproate, phenytoin sodium, and carbamazepine affected levetiracetam levels when given concomitantly. Levetiracetam dose was adjusted in 61 patients with abnormal levels for better clinical response. Good seizure control was noted in 913 (82.47%) patients whose levels were within TR, whereas 136 (58.62%) patients with low levels reported an increase in seizure frequency. Conclusions: The modified HPLC-UV method is simple, rapid, efficient, and reliable for assaying serum levetiracetam. [ABSTRACT FROM AUTHOR]

Famotidine (FAM), a histamine H2 receptor antagonist, is effective against peptic ulcers and Zollinger Ellison syndrome. In the current investigation, a HPLC approach was developed to detect the Famotidine (FAM) in pre-clinical samples (rat plasma). To get rid of any chromatographic solvent effects, methanolic extraction method was used to prepare biological samples. A C18 column was used for chromatographic separation, with a pH-adjusted to 8 as mobile phase of water, methanol, and acetonitrile (70: 20: 10, v/v/v) at a flow rate of 1 mL/min and UV detection at 264 nm. The retention times of FAM was found to be 5.7 min. The technique was linear in the range of 50 to 1400 ng/mL in plasma concentration with R2 of 0.9985. The newly proposed method's respective limits for quantification and detection were found to be 151.45 ± 6.47 ng/mL and 49.97 ± 2.14 ng/mL. The average recovery rates were discovered to range from 98.06 to 103.56%. After numerous freeze-thaw cycles of the treated plasma samples, analyte was stable and showed no sign of significant deterioration. After a single oral dose of 10 mg/kg of FAM, the approach was effectively used to assess the pharmacokinetic characteristics in Wistar albino rats. Consequently, the straightforward technique would enable quick with affordable detection of the FAM from biological samples. [ABSTRACT FROM AUTHOR]

Introduction: In this study, a new high performance liquid chromatographic method was developed to determine the amount of allicin (AL) and s-allyl cysteine (SAC) in Allium sativum L. extracts. Methods: In the method, C18 column (5 µm x4.6 mm x150 mm) was used as the stationary phase at 25 °C and acetonitrile: water (70:30, v/v) mixture was used as mobile phase with 1 mL/min flow rate. Isocratic elution was applied. The injection volume was 20 µL. Measurements were carried out at 254 nm with ultraviolet detection. Retention times for AL and SAC were 1.1 and 2.4 min, respectively. The method was validated according to International Conference on Harmonization criteria. Results: The limit of detection values for AL and SAC were 0.6 µg/mL and 1.5 µg/mL, respectively. The limit of quantitation values for AL and SAC were 2 µg/mL and 5 µg/mL, respectively. The linearity of the method was between 2-100 µg/mL and 5-30 µg/mL for AL and s-allyl cysteine, respectively. The developed method was also validated and applied to three different trade extracts. Conclusion: This new method, which is quite fast, simple and economical, can be used in the analysis of Allium sativum L. extracts, which are named as black garlic in the contents of food supplements. [ABSTRACT FROM AUTHOR]

Background: Transthyretin amyloidosis is a rare disease currently under wide investigation and many different therapeutic agents were developed for its control and treatment. In addition to the newly discovered drugs, it was also observed drug repurposing of some wellstudied therapeutic agents. Diflunisal was developed in 1971 as an anti-inflammatory and analgesic drug but showed good results when used as a kinetic stabilizer of the transthyretin protein. Objectives: Present study describes a high-performance liquid chromatography method for its determination in bulk drug and human plasma by UV detection. Materials and Methods: Isocratic elution of the mobile phase (consisting of 0.1% trifluoroacetic acid in water and acetonitrile in the ratio 42:58 v/v) at a flow rate 1.0 ml/min was set and the developed analytical procedure became fast and simple. Chromatographic determination was performed on a Purospher® RP - 18 column at room temperature and a UV detector set at 230 nm. Results: The developed method was validated for linearity in the range 0.5-125 µg/ml for the bulk drug and 0.48-120 µg/ml for plasma. Calibration curves were linear over the selected ranges with correlation coefficients (R2) greater than 0.999. The coefficients of variation for intra- and interassay were <2% for both methods - bulk drug and plasma determination. Conclusion: The developed effective and specific method can be applied in routine clinical practice for drug therapy monitoring. [ABSTRACT FROM AUTHOR]

A highly fluorinated porphyrin-based covalent organic frameworks magnetic adsorbent (FPy-COF@PDA@Fe3O4) was fabricated by using polydopamine (PDA) grafting Fe3O4 nanospheres as magnetic core and FPy-COF as shell for magnetic solid phase extraction (MSPE) of fluoroquinolones (FQs). FPy-COF was constructed by using 5,15-bis(4-aminophenyl)-10,20-bis(perfluorophenyl)porphyrin and 4,4′-biphenyldicarboxaldehyde as two building blocks. PDA as a bridge grafting on the surface of Fe3O4 nanospheres facilitated the growth of FPy-COF. The morphology and structure of FPy-COF@PDA@Fe3O4 adsorbent were characterized in detail. The prepared magnetic adsorbent exhibited good extraction capability to amphiphilic FQs due to their superior chemical affinities such as fluorophilic interaction and hydrogen-bond interaction from nitrogen-rich skeleton. Under the optimized conditions, the MSPE method combined with high performance liquid chromatography with ultraviolet detection (HPLC–UV) was developed to sensitively quantify trace level of six FQs in milk samples. The developed MSPE-HPLC method showed good linearity with wide concentration range, precision, and low limits of detection (S/N = 3) for six FQs as low as 2.3 ngꞏmL−1 in milk. The extraction recoveries of different spiked concentrations were in the range 77.8–110.4% for milk samples with RSD less than 9.7%. [ABSTRACT FROM AUTHOR]

The classic Astragalus-Cassia twig drug pair has a long history of proven efficacy. However, a fewer studies on material basis of the Astragalus and Cassia twig decoction (ACD) was researched at present. The method of UPLC-Q-TOF-MS for classifying and identifying the main chemical components of ACD was established and the differences in composition between single decoction and co-decoction were compared by using HPLC-UV. The therapeutic role of ACD on type 2 diabetes (T2D) rats was investigated. Thirty-five compounds were resolved from the ACD. Fifteen compounds were deduced from the decoction of Astragalus, whereas nine compounds were identified from Cassia twig. Pairing of herbs make a significant effect on the chemical composition of herbal decoction. ACD can play a more obvious role in alleviating the symptoms of T2D rats, compared to the application of single herb. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Phthalic acid as switchable-hydrophilicity solvent for the extraction of sildenafil. • No sample cooling is required for the solidification of phthalic acid. • The analytical protocol is rapid using environmentally friendly solvents. Herein, a green liquid phase microextraction protocol using phthalic acid as switchable hydrophilicity solvent (SHS) is reported for the quantification of sildenafil in authentic human urine. The analyte was extracted onto phthalic acid solid particles which were produced through acidification of the sample. Its solidification was accomplished at ambient conditions without sample cooling. The determination of the sildenafil was carried out using high performance liquid chromatography-ultraviolet detection (HPLC-UV). The microextraction parameters that affect the extraction efficiency of the drug (i.e. SHS type and its concentration, acid type and concentration, extraction time, filter type) have been studied. The optimized analytical protocol involved the mixing of 300 μL of phthalate solution (0.75 M) with 600 μL of sample, followed by the addition of 50 μL of concentrated H 3 PO 4. The produced solid was collected using membrane syringe filter (0.45 μm) and was finally dissolved in 500 μL of CH 3 OH. Method validation data showed determination coefficient ≥ 0.99 for the linear range of 50 – 2000 ng/mL. The limit of detection (LOD) and the lower limit of quantitation (LLOQ) were 30 and 100 ng/mL, respectively. The accuracy (expressed as % recovery) of the method ranged between 88.0 – 108.9 % while the precision (expressed as % RSD) was less than 17.8 % in all cases. The robustness of the microextraction procedure and the instrumental method were investigated using Plackett-Burman experimental designs. The applicability of the method was demonstrated by analyzing both spiked and authentic human urine samples after oral administration of drug-containing pharmaceutical formulation. The developed protocol offers cost-efficiency, handling simplicity, and high throughput. Its green character was evaluated using Green Analytical Procedure Index and Blue Applicability Grade Index. [ABSTRACT FROM AUTHOR]

Personalized medicine is a rapidly revolving field that offers new opportunities for tailoring disease treatment to individual patients. The main idea behind this approach is to carefully select safe and effective medications and treatment plant based on each patient's unique pharmacokinetic profile. Isoniazid is a first-line anti-tuberculosis drug that has interindividual variability in its metabolic processing, leading to significant differences in plasma concentrations among patients receiving equivalent doses. This variability necessitates the creation of individualized treatment regimens as part of personalized medicine to achieve more effective therapy. In this work, a deep eutectic solvent-based liquid-liquid microextraction approach for the separation and determination of isoniazid in human plasma by high-performance liquid chromatography with UV–Vis detection was developed for the first time. A new natural deep eutectic solvent based on thymol as a hydrogen bond donor and 4-methoxybenzaldehyde as a hydrogen bond acceptor was proposed as the extraction solvent. The developed microextraction procedure assumed two simultaneous processes during the mixing of the sample and extraction solvent: the derivatization of the polar analyte in the presence of 4-methoxybenzaldehyde (component of the natural deep eutectic solvent) with the formation of a hydrophobic Schiff base (1); mass transfer of the Schiff base from the sample phase to the extraction solvent phase (2). Under optimal conditions, the limits of detection and quantification were 20 and 60 μg L−1, respectively. The RSD value was <10 %, the extraction recovery was 95 %. In this work, the possibility of isoniazid derivatization in the natural deep eutectic solvent phase with the formation of the Schiff base was presented for the first time. The approach provided the separation and preconcentration of polar isoniazid without the use of expensive derivatization agents and solid-phase extraction cartridges. The formation of the Schiff base was confirmed by mass spectrometry. [Display omitted] • New natural deep eutectic solvent (NADES) based on thymol and 4-methoxybenzaldehyde. • Derivatization of isoniazid to Schiff base in NADES. • NADES as a reagent for isoniazid derivatization and as an extraction solvent. • Fast HPLC-UV determination of isoniazid in human plasma. [ABSTRACT FROM AUTHOR]

[Display omitted] • BPL is a common chemical inactivating reagent used in vaccines. • Via BPL carcinogenicity, its residual should be hydrolyzed completely in vaccines to avoid cytotoxicity. • BPL residual determination in vaccines is challenging due to its low concentration, presence in a complex mixture of vaccine and lack of suitable chromophore. • BPL derivatization with RBH was used to enhance analytical sensitivity and stabilize the BPL molecule for measurement with HPLC-UV. β-propiolactone (BPL) is an alkylating agent used for inactivation of biological samples such as vaccines. Due to its known carcinogenic properties, complete hydrolysis of BPL is essential, and the detection of trace amounts is crucial. In this study a novel High-Performance Liquid Chromatography-Ultraviolet (HPLC-UV) method was developed. Rhodamine B hydrazide (RBH) was synthesized and utilized as a derivatizing reagent to react with BPL. The reaction was optimized in a weak acidic solution, resulting in a high yield. The separation of the RBH-derivatized BPL was achieved on a C8 column and detected by a UV detector at a wavelength of 560 nm. The method's validation demonstrated a high linearity (r2 > 0.99) over a concentration range of 0.5–50 µg/mL, with detection and quantification limits of 0.17 µg/mL and 0.5 µg/mL, respectively. The average recovery of samples was 85.20 % with a relative standard deviation (RSD) of 1.75 %. This method was successfully applied for BPL residue analysis in inactivated COVID-19 vaccines. This novel derivatization method offers a promising solution for monitoring BPL residues in the vaccine production process for quality control purposes and compliance with regulatory standards. [ABSTRACT FROM AUTHOR]

Atractylis aristata batt., as an endemic plant from the Asteraceae family, holds a significant position in the Ahaggar region of southern Algeria's traditional medicine. The aerial parts of Atractylis aristata was used to cure inflammation, fever, and stomach disorders. The objective of the present investigation was to ascertain the overall bioactive components and phytochemical components and examine the antioxidant, antidiabetic, anti-inflammatory, acute toxicity, and sedative properties of the crude extract obtained from the aerial portions of Atractylis aristata (AaME). The AaME's antioxidant activity was assessed by the use of pyrogallol autoxidation, (1,1 diphenyl-2-picrylhydrazyl) (DPPH), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and reducing power (RP) techniques. 1 mg/mL of AaME was used to evaluate the antidiabetic activity by applying the enzyme α -amylase inhibitory power test. At the same time, the bovine serum albumin (BSA) denaturation method was employed to quantify the in vitro anti-inflammatory activity at different concentrations (1.5625, 0.78125, 0.390625, 0.1953125 and 0.09765625 mg/mL). In contrast, following the Organization for Economic Co-operation and Development (OECD) guideline No. 423, which covers acute oral toxicity testing protocols, the limit dosage test was employed to assess in vivo acute toxicity. At the dose of 0.08 mg/mL, the carrageenan-induced paw edema approach was used to assess the anti-inflammatory efficacy in vivo , and the sedative activity was carried out at the dose of 0.08 mg/mL using the measurement of the locomotor method. Different bioactive compounds were identified within AaME using LC-MS/MS and HPLC-UV analysis. The acute toxicity study showed no fatalities or noticeable neurobehavioral consequences at the limit test; this led to their classification in Globally Harmonized System (GHS) category Five, as the OECD guideline No 423 recommended. At a concentration of 0.08 mg/mL (2000 mg/kg), AaME showed apparent inhibition of paw edema and a significant (p = 0.01227) reduction in locomotor activity compared to the control animals. Our findings showed that AaME exhibited considerable antioxidant (IC 50 = 0.040 ± 0.003 mg/mL (DPPH), IC 50 = 0.005 ± 5.77 × 10-5 mg/mL (ABTS), AEAC = 91.15 ± 3.921 mg (RP) and IR% = 23.81 ± 4.276 (Inhibition rate of pyrogallol) and rebuts antidiabetic activities (I% = 57.6241% ± 2.81772). Our findings revealed that the maximum percentage of BSA inhibition (70.84 ± 0.10%) was obtained at 1.562.5 mg/mL. Thus, the AaME phytochemical profile performed using phytochemical screening, HPLC-UV, and LC-MS/MS analysis demonstrated that A. aristata can be a valuable source of chemicals with biological activity for pharmaceutical manufacturers. The phytochemical profiling, determined through HPLC-UV and LC-MS/MS applications, reveals this plant's therapeutic value. The aerial parts of Atractylis aristata contain bioactive molecules such as gallic acid, ascorbic acid, and quercetin, contributing to its significant antioxidant capabilities. Furthermore, identifying alizarin, the active compound responsible for its anti-inflammatory properties, could provide evidence supporting the anti-inflammatory capabilities of this subspecies. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Resins from Boswellia exhibit species-specific variations in AKBA and KBA content. • NIR spectra of Boswellia resin confirm species-dependent nature of resin samples. • Principal component analysis shows clear separation of Boswellia species. • Prediction of boswellic acid levels in solid resin was achieved with NIRS and PLSR. The bioactive compounds Acetyl-11-keto-β-boswellic acid (AKBA) and 11-keto-β-boswellic acid (KBA), found in the resin of the Boswellia tree, exhibit anti-inflammatory properties, rendering Boswellia resin an intriguing natural medicinal products. However, the content of boswellic acids varies across different Boswellia species and proper knowledge of its species-dependent nature, as well as alternatives to the resource- and time-intensive HPLC analysis, are lacking. Here we present a comprehensive investigation into the boswellic acid content of seven Boswellia species from ten countries and introduce a novel and non-destructive Near-Infrared spectroscopy method for predicting boswellic acid concentrations in solid resin samples. The HPLC-UV reference analysis revealed AKBA concentrations of up to 7.27 % (w/w) with KBA concentrations reaching up to 1.28 % (w/w). Principal Component Analysis of the HPLC and NIR spectroscopy data unveiled species-specific variations, facilitating differentiation based on boswellic acid content, characteristic chromatograms and NIR spectra. Using the HPLC-UV quantification as reference, we developed a Partial Least Squares regression model based on NIR spectra of the resin samples. This model demonstrated highly satisfactory predictive capabilities for AKBA content, achieving a root mean square error of prediction of 0.74 % (w/w) and an R2 val of 0.79 in independent test set validation. Although the model was less effective for predicting KBA content, it still offered valuable estimates. The spectroscopic method introduced in this study provides a cost-effective and solvent-free approach for predicting boswellic acid content, demonstrating the potential for application in non-laboratory settings through the use of miniaturized NIR spectrometers. Consequently, this method aligns well with the principles of green chemistry and addresses the growing demand for alternative analytical techniques. [ABSTRACT FROM AUTHOR]

• Functonalization of polyurethane sponge with graphitic materials. • Development of In-tube SPE method. • Extraction of drug residues from food samples. • HPLC method development for the determination of drug residues. Veterinary drugs used in animal husbandry raise public health concerns due to their residues in the bodies of animals. This study employs a simple and quick sample preparation technique, in-tube solid phase extraction, to extract drug residues from foodstuffs, including eggs, honey, and water. This technique utilizes the synergy of graphitic-based materials and polyurethane sponges (PU) combined through dip coating method to make reusable sorbents for extracting drugs, including amoxicillin, paracetamol, ciprofloxacin, and cefixime. These prepared sorbents were characterized using FTIR, SEM, and XRD. HPLC analysis assessed the extraction efficiency, considering various parameters such as analyte concentration, sample solution pH, extraction time, type of eluting solvent, and graphitic-based polyurethane sponge reusability and stability. The proposed method exhibited a linear response for all three sorbents in the range of 0.03–1000 µg mL−1, with LOD 0.03–1.60 µg mL−1 and LOQ 0.18–4.84 µg mL−1. The % RSD ranged from 1.3 to 9.3 %, with recoveries of up to 98.42 %. [ABSTRACT FROM AUTHOR]

This study aimed to establish a validated HPLC-UV analytical method for the determination of gallic acid, catechin, scopoletin, and umckalin in phytoformulations containing P. sidoides. Also, to assess the anti-SARS-CoV-2 effect of P. sidoides and these biomolecules in vitro. An HPLC-UV method was developed and verified by testing the commercial forms, Kalobin® and Umca®. It revealed low detectable scopoletin and high umckalin levels. Pelargonium sidoides exhibited a significant reduction of SARS-CoV-2-induced cytopathic effect in Vero E6 cells (IC50 13.79 μg/mL and selectivity index, SI 6.3), whereas scopoletin showed a remarkable anti-SARS-CoV-2 activity with better selectivity (IC50 17.79 μg/mL and SI 14.22). An in-silico prediction of the drugability indicated that the studied biomolecules are under the acceptable norms of Lipinski's rule, water-soluble, and showed high GIT absorption and bioavailability. Docking study towards the essential molecular targets for viral replication and entry of SARS-CoV-2 indicated good binding affinity of scopoletin (−6.4 Kcal/mol) towards the interface region between the SARS-CoV-2 spike protein RBD and the ACE2 surface receptor indicating the probability of interference with the viral entry to the human cells and showed H-bonding with His-41 in the active site of the main protease which may explain its high antiviral activity. [ABSTRACT FROM AUTHOR]

[Objectives] To establish a HPLC-UV method for the determination of Cistanches Herba in Zhenrongdnn mixture. [Methods] According to the content determination method of Cistanches Herba in the 2020 edition of Chimese Pharmacopoeia, using HPLC-UV method, the content determination method of Cistanches Herba in Zhenrongdan mixture was established, and the content of echinacoside was determined. The related chromatographic conditions were explored, and the methodological investigation was caried out. [Results] The chromatographic conditions were determined as flows: octadecylsilane bonded silica gel a filler (C18) ; 80% acetonitrile solution (containing 0. 2% phosphoric acid) -0.2% phosphoric acid aqueous solution (15:85) a mobile phase; detection wavelength was 330 nm. The number of theoretical plates should not be lees than 3 000 according to the peak of echinacoside. The methodological investigation showed that the method had better precision, accuracy and repeatability. Under the conditions of this study, echinacoside had better linear relationship in the range of 74.9 - 1 498 ng, and the average recovery was 99. 1 %, RSD = 0.5% (n = 6). [Conclusions ] A method for the determination of Cistanches Herba in Zhenrongdan mixture by HPLC-UV was established. The method is sensitive, rapid, accurate and suitable for the determination of Cistanches Herba in Zhenrongdan mixture. [ABSTRACT FROM AUTHOR]

The ongoing development of more and more new psychoactive substances continues to be a huge problem in 2022 affecting the European and international drug market. Through slight alterations in the structure of illicit drugs, a way to circumvent the law is created, as the created derivatives serve as legal alternatives with similar effects. A common way of structure modification is the induction of a halogen residue. Recently, halogenated derivatives of the well-known designer drug 4-methylaminorex appeared on the market and are available in various online shops. In this study, three novel halogenated 4-methylaminorex derivatives, namely 4′-fluoro-4-methylaminorex, 4′-chloro-4-methylaminorex, and 4′-bromo-4-methylaminorex, were purchased online and characterized using nuclear magnetic resonance (NMR) spectroscopy, liquid chromatography-high-resolution mass spectrometry (LC-HRMS), and chiral high-performance liquid chromatography with ultraviolet detection (HPLC-UV). These derivatives possess two stereogenic centers, and analyses revealed that all of them were present as a racemic mixture of the trans diastereomeric form. [ABSTRACT FROM AUTHOR]

In many countries, buckwheat is considered an alternative gluten-free food product with a unique set of proteins and amino acid composition, and also the high antioxidant activity (AOA). This study deals with the assessment and comparison of the AOA and the total concentration of free phenolic compounds in various buckwheat products purchased from supermarkets in four countries. It is shown that the optimal extractant of free phenols from buckwheat grain is a 50% water–ethanol solution; vortexing without heating is sufficient for extraction. Using high-performance liquid chromatography with a diode array detector, fluorescence and MS detectors, the dominant components are quantitatively determined in all buckwheat samples: rutin ((6.7–14.1) × 10–2 g/kg), flavan-3-ols (catechin (1.8–8.7) × 10–2 g/kg and epicatechin (2.5–11.6) × 10–2 g/kg). Protocatechuic and gallic acids, as well as unbound vitexin and quercetin, are detected in minor amounts mainly in heat-treated buckwheat grains. Linear correlations between the total concentration of phenolic compounds, estimated by the Folin–Ciocalteu method, and AOA, as well as between the sum of concentrations of three components (rutin, catechin, and epicatechin) and AOA are obtained. The chromatographic profiles and AOA of buckwheat, wheat, barley, corn, and rice are compared. [ABSTRACT FROM AUTHOR]

A new, rapid, efficient, low cost, robust, accurate and reproducible analytical method for the determination of Paraquat has been developed using reverse phase high performance liquid chromatography with UV-Visible detector (HPLC-UV). Paraquat is a frequently used herbicide. This method is useful for the detection and quantification of paraquat in raw materials and commercial samples with excellent recoveries upto almost 100%. pH of the mobile phase (acetonitrile:methanol:water 1:1:2) was optimized as 2.5 with ortho-phosphoric acid. This analytical method was validated with excellent linearity R² = 0.999. LOD and LOQ were calculated to be 0.74 mg/L and 2.45 mg/L, respectively. The method showed a high precision (RSD%) value of 0.32, while the accuracy measured in terms of percentage recovery was almost 100% under optimized conditions. The robustness of the method was studied by changing the flow rate and the mobile phase concentration ratios, and the results obtained were within the permissible accepted values. [ABSTRACT FROM AUTHOR]

Background: Northern Italy has an enormous heritage of hop biodiversity that need to be exploited and studied. The preservation and valorization through the characterization of the existent biodiversity is a primary goal of the European Green Deal 2023–2030. The aim of this study was to acquire information on the biodiversity of Italian wild hops. Methods: Genetic characterization of sixty accessions was done resorting to Single Sequence Repeated (SSR) markers. Phytochemical characterization of wild hops was achieved using: (i) high-performance liquid chromatography with ultraviolet detection for bitter acids quantification, (ii) steam distillation for essential oils quantification and (iii) Gas Chromatography-Mass Spectrometry for the determination of the aromatic profile. Results: The eight SSR primers showed high Polymorphic Information Content (PIC), especially HlGA23. α-Acids reached values between 0 and 4.125. The essential oils analysis highlighted variability within the studied population, with some accessions characterized by important spicy fraction, and others by fruity and floral notes. Conclusions: The present study allowed the characterization of Italian wild hops and demonstrated an interesting biodiversity. Part of this biodiversity have been shown to be potentially suitable for use in brewing. Moreover, several genotypes could be used in breeding programs to obtain new more sustainable varieties. [ABSTRACT FROM AUTHOR]

A mitochondrial electron transport chain member complex I inhibitor, amobarbital, can reduce oxidative damage and chondrocyte death, eventually preventing post-traumatic osteoarthritis (PTOA). Viscosupplementation using a crosslinked hyaluronic acid (HA) hydrogel is currently applied clinically for knee OA pain relief. In this work, we utilized the HA hydrogel as a drug delivery vehicle to improve the long-term efficacy of amobarbital. Here we evaluated the pharmaceutic stability of amobarbital when dispersed in a crosslinked HA hydrogel formulated in proportions intended for clinical use. We validated a high-performance liquid chromatography with an ultraviolet detector (HPLC-UV) method following International Conference for Harmonization Q2(R1) guidelines to ensure its suitability for amobarbital detection. The feasibility of this formulation's drug delivery capability was proven by measuring the release, solubility, and drug uniformity. The amobarbital/HA hydrogel showed comparable amobarbital stability in different biological fluids compared to amobarbital solution. In addition, the amobarbital/HA hydrogel imparted significantly greater drug stability when stored at 70°C for 24 hours. In conclusion, we confirmed the pharmaceutical stability of the amobarbital/HA hydrogel in various conditions and biological fluids using a validated HPLC-UV method. This data provides essential evidence in support of the use of this amobarbital/HA formulation in future clinical trials for PTOA treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three-component DES for reversed-phase air-assisted liquid–liquid microextraction. • First microextraction of furanic compounds in DES from transformer oil. • Effect of furanic compounds structure on extraction efficiency in DES. • Green and fast procedure for determination of furanic compounds in transformer oil. In this work, a revered-phase air-assisted liquid–liquid microextraction approach based on three-component deep eutectic solvent for pretreatment of petroleum oils was developed. The approach was utilized for the determination of furanic compounds in aged transformer oil by high-performance liquid chromatography with UV detection. The procedure assumed multiple aspiration of oil sample and deep eutectic solvent into a syringe and injection of the extraction mixture into an Eppendorf tube (11 instant extraction cycles). This process resulted in the formation of a cloudy solution, attributed to the dispersion of extraction solvent droplets into the oil sample. After centrifugation the obtained extract phase was introduced into a chromatographic system without additional purification and dilution. To establish the optimal microextraction procedure conditions, key parameters such as the extraction solvent composition, phase ratio and the number of extraction cycles were investigated. Cheap and available low viscosity deep eutectic solvent based on choline chloride, acetic acid and water provided the highest extraction recovery values (from 85 to 96 %). It was found, that acetic acid as precursor of extraction solvent acted key-role for maximum extraction recovery for all analytes. The phenomenon of the influence of hydroxyl groups in the structure of analytes on the extraction efficiency was revealed. Under optimal condition, the limits of detection were in the range from 3 to 6 μg L−1. [ABSTRACT FROM AUTHOR]

[Display omitted] • Selective and sensitive method was developed for acetochlor and metolachlor quantification by HPLC-UV. • Vortex-assisted dispersive liquid–liquid microextraction procedure was optimized. • Optimized methods provided good repeatability (RSD < 10 %) and high recoveries (>80 %). • Optimized DLLME enabled the quantification of acetochlor and metolachlor at levels as low as 3–4 µg/L. In this study, we developed a method that is sensitive, simple, and environmentally friendly for quantifying acetochlor and metolachlor. This method combines vortex-assisted dispersive liquid–liquid microextraction (DLLME) with high-performance liquid chromatography (HPLC). HPLC operating parameters and extraction parameters for direct and post-extraction analyses of acetochlor and metolachlor were optimized by employing the Taguchi experimental design method. The optimized HPLC parameters for acetochlor and metolachlor were 1.00 mL/min and 1.2 mL/min flow rate, 40 °C column temperature, and 70/30 (ACN/Water) and 80/20 (ACN/Water) at 210 and 230 nm wavelengths, respectively, for the direct injection method. For the DLLME procedure, 1,2-dichloroethane extraction solvent type, acetonitrile, and methanol dispersive solvent type, 400 µL and 300 µL extraction solvent volumes, and 1.0 mL dispersive solvent volume were the optimized DLLME extraction parameters, respectively. The developed and optimized methods for acetochlor and metolachlor analyses exhibited satisfactory validation results, with excellent linearity, indicated by R2 values greater than 0.99. The limit of detection (LOD) and the limit quantification (LOQ) levels of acetochlor and metolachlor were 28.96 to 31.25 µg/L, and 86.87 to 93.75 µg/L for direct injection, and 1.15 to 1.24 µg/L and 3.47 to 3.75 µg/L for post-extraction, respectively. The DLLME recovery values were within the range of 82.6–99.2 % (relative standard deviations-RSD: 4.47–10.13 %) for acetochlor and 91.1–103.4 % (4.31–7.96 %) for metolachlor. Repeatability and reproducibility results (n = 10) of direct injection and post-extraction methods for fortified acetochlor and metolachlor samples displayed very high precision lower than 2 % RSD. [ABSTRACT FROM AUTHOR]

A new derivatization high-performance liquid chromatography method with ultraviolet detection was developed and validated for the quantitative analysis of methanesulfonate genotoxic impurities in an innovative drug for the treatment of non-alcoholic fatty liver disease. In this study, sodium dibenzyldithiocarbamate was used as a derivatization reagent for the first time to enhance the sensitivity of the analysis, and NaOH aqueous solution was chosen as a pH regulator to avoid the interference of the drug matrix. Several key experimental parameters of the derivatization reaction were investigated and optimized. In addition, specificity, linearity, precision, stability, and accuracy were validated. The determined results of the samples were consistent with those obtained from the derivatization gas chromatography–mass spectrometry analysis. Thus, the proposed method is a reliable and practical protocol for the determination of trace methanesulfonate genotoxic impurities in drugs containing mesylate groups. [ABSTRACT FROM AUTHOR]

Curcumin (CUR) and D-panthenol (DPA) have been widely investigated for wound-healing treatment. In order to analyse these two compounds from a dosage form, such as polymer-based wound dressings or creams, an analytical method that allows the quantification of both drugs simultaneously should be developed. Here, we report for the first time a validated high-performance liquid chromatographic (HPLC) method coupled with UV detection to quantify CUR and DPA based on the standards set by the International Council on Harmonization (ICH) guidelines. The separation of the analytes was performed using a C18 column that utilised a mobile phase consisting of 0.001% v/v phosphoric acid and methanol using a gradient method with a run time of 15 min. The method is linear for drug concentrations within the range of 0.39–12.5 μg mL−1 (R2 = 0.9999) for CUR and 0.39–25 μg mL−1 for DPA (R2 = 1). The validated method was found to be precise and accurate. Moreover, the CUR and DPA solution was found to be stable under specific storage conditions. We, therefore, suggest that the HPLC-UV method developed in this study may be very useful in screening formulations for CUR and DPA within a preclinical setting through in vitro release studies. [ABSTRACT FROM AUTHOR]

This study was aimed at developing a double-monitoring detection system for measuring the TAC (total antioxidant capacity) of apple juice samples. The conventional CUPRAC (cupric ion reducing antioxidant capacity) assay was coupled to high-performance liquid chromatography–ultraviolet (HPLC–UV) and digital image-based colorimetric detection systems. In the CUPRAC assay, a chromogenic copper(II)-neocuproine (Cu(II)-Nc) reagent was used to oxidize the antioxidants, which is further reduced by the antioxidants to a yellow-colored copper(I)-neocuproine (Cu(I)-Nc) chelate having maximum absorption at 450 nm. The yellow-colored samples were measured by HPLC–UV and digital image-based colorimetric detection systems. Parameters of the HPLC–UV system were optimized to obtain a sharp and transient peak at 450 nm analytical wavelength. Under the optimum experimental conditions, the detection limits calculated for ascorbic acid using the HPLC–UV and digital image-based colorimetric detection systems were 0.28 and 0.70 mg/L, respectively. Satisfactory results (95.6–102%) were calculated for apple juice samples spiked at different concentrations for both detection systems, and very low (< 5.0%) percent relative standard deviation values were recorded. The TAC value for ascorbic acid equivalent in apple juice sample was found as 131 ± 0.1 mg/L using the HPLC–UV system. [ABSTRACT FROM AUTHOR]

The pharmacokinetic profiling of active compounds is necessary for drug development and application. Approaches to a pharmacokinetic study based on biological markers are alternatives to traditional approaches based on chromatographic methods. The aim of the study was to compare two analytical approaches to pharmacokinetics investigation for an example of sitagliptin in rabbits after one dose oral administration. The method for sitagliptin quantification in rabbit plasma samples based on a correlation between its concentration and dipeptidyl peptidase IV activity was proposed, validated, and applied. The high‐performance liquid chromatography (HPLC)‐ultraviolet (UV) method was also validated and applied for the same sample analysis. The plasma pharmacokinetics of sitagliptin after oral administration to the rabbits in one dose was characterized after two analytical assays. The close values of the main pharmacokinetic parameters were obtained after two approaches. The nontraditional approach based on correlation of special marker activity and active substance concentration appears to be more sensitive than HPLC‐UV. Thus, the sitagliptin concentrations determined by biomarker assay were higher than the lower limit of quantification (LLOQ) for a longer period (more timepoints) than after the HPLC‐UV assay. This feature may influence the values of some calculated concentration‐dependent (area under the curve [AUC]0‐t, etc.) and time‐dependent parameters (mean residence time [MRT], T1/2, etc.). The values of Tmax obtained by the two approaches were similar and adequate for oral drug administration that confirms the correctness of biomarker selection for pharmacokinetics assessment. The obtained results on the example of sitagliptin confirms that the biomarker approach is adequate and applicable for a pharmacokinetics study. Similar approaches may be effective for individual compounds and complex mixtures when it is difficult or impossible to analyze them traditionally by chromatographic methods. [ABSTRACT FROM AUTHOR]

A high-performance liquid chromatography (HPLC) method endowed with a gradient elution and a UV detection system was established and validated for the determination of phenolic acids, phenolic alcohols, hydroxycinnamic acid derivatives, flavonoids, secoiridoids and lignans during olive (Olea europaea L.) fruit development (green, purple and black olives). Within the test range, the calibration curves exposed a good linear regression (R2>0.9995). Detection limits ranged between 0.63 and 13.43 mg/L for the detected phenolic compounds. The presented method yielded satisfactory repeatability in terms of retention times and average concentrations of phenolic compounds (RSD < 0.3%). Verbascoside was established as the major phenolic compound in black olives. Oleuropein was established as the dominating phenolic compound in green olives, and its level decreased during maturation. Additionally, this research is the first to experimentally evidence that the flavone luteolin-7-rutinoside is the predominant flavonoid glucoside in black olives, showing the most significant variation with fruit development. The above results validate the method for an easy and fast determination of different classes of phenolic compounds present in olive fruits. [ABSTRACT FROM AUTHOR]

It is an analytical requirement to identify and determine high molecular weight APIs in pharmaceutical forms. For this reason, it is aimed to develop and validate an analytical method for the determination of hyaluronic acid in pharmaceutical form in this study. 0.1 M Na2SO4 was prepared as mobile phase. The separation of compound was performed with a OHpak Shodex SB-806M HQ (13 µm, 8,0 x 300mm, Japan) analytical column. Guard column which is OHpak SB-G, (8 µm, 100 Å, 6.0 x 50 mm, Japan) was integrated to the system before the analytical column. UV detection at 198 nm was used to monitor the eluent and flow rate of the mobile phase was set to 1 mL/min. The method has been validated in terms of system suitability, linearity, limits of detection (LOD) and quantity (LOQ), precision, accuracy, specificity, selectivity, and stability. The obtained findings showed that the analytical method has linearity higher than 0.99, accuracy, precision, selectivity and stability. The method was found to be precise, accurate and specific during the study. [ABSTRACT FROM AUTHOR]

Background: Linezolid (LNZ), an oxazolidinone antibiotic, has 100% oral bioavailability and favorable activities against gram-positive pathogens. The in vitro PK/PD model was developed based on concentrations obtained with routine doses in humans can be used to guide dose optimization in the clinic. Methods: In this study, we employed an in vitro PK/PD model to simulate the changes in the plasma concentration of linezolid in the human body against a clinical isolate of MRSA in vitro. A high-performance liquid chromatography (HPLC)-UV method was applied to measure the concentration of linezolid. Bacterial samples were collected at different times from the central compartment for count. Results: The chromatographic separation was carried out with an AichromBond-AQC18 column(250mm× 4.6mm, 5μm), using a mobile phase of water with 0.1% formic acid:acetonitrile 70:30 (v/v), followed by detection at 254 nm, and a single detection run was completed within 10 min. The method was validated by estimating the precision and accuracy for the inter- and intra-day analyses in the concentration range of 0.25– 32 mg/L. The method was linear over the investigated range of 0.125– 32 mg/L, with all correlation coefcients R2 = 0.9999. The intra-day and inter-day precisions were within 7.598%, and the method recovery ranged from 90.912% to 106.459%. In vitro PK/PD model, both the absorption and elimination of linezolid being simulated can be precisely controlled by computer. In the control group, the bacterial reached 7.9 Log10CFU/mL in the rst 48h and maintained until the end, indicating that the colonies grew well in vitro PK/PD model. In the linezolid 600 mg q12h administration group, the colony decreased to 2.39 Log10CFU/mL at 24h, showing a good bactericidal effect; however, the colonies resumed growth to the initial level in 48h, indicating an emergence of resistance. Conclusion: We successfully established an in vitro infection PK/PD model and developed an HPLC-UV method to determine linezolid concentration for resistance investigation. The results suggest that the 600 mg q12h dosing regimen may no longer be applicable and requires optimization. [ABSTRACT FROM AUTHOR]

The principle aim of this work is to evaluate the antimicrobial and antiochratoxic power of the essential oil of Mentha spicata (EOM). This oil was obtained by hydrodistillation with a yield of 0.3%. EOM was screened for its possible antibacterial activity in vitro against five strains of pathogenic bacteria, using the solid disc diffusion method and the microdilution method. The extract reacted positively to the bacterial strains tested. The results of the antifungal activity show an inhibition of mycelial growth; it is total on Aspergillus ochraceus, Aspergillus flavus, Aspergillus niger, Penicillium viridicatum, and on Rhizopus stolonifer and Alternaria alternate at a concentration of 12.5 μl/ml. Tests carried out on yeasts mainly referenced as Candida albicans IP444 and Candida albicans 2679 showed minimal inhibition (MIC) of the order of 7.81 μl/ml and 0.97 μl/ml, respectively and theMICis of the order of 0.48 μl/ml for Candida albicans 10 231. In addition, the EOM antiochratoxigenic test for ochratoxin A production capacity following a series of high performance liquid chromatography separation and ultraviolet detection (HPLC--UV) analyses detected an inhibitory effect proportional to the EOM concentration. In general, the essential oil showed an effective antimicrobial action on the growth of the tested pathogens and an antiochratoxigenic. [ABSTRACT FROM AUTHOR]

As a universal quorum sensing (QS) signal, autoinducer-2 (AI-2) is utilized by both Gram-negative and Gram-positive bacteria to coordinate several group behaviors, such as biofilm formation, virulence, and motility, when the bacterial cell density exceeds the thresholds. The determination of the AI-2 level is essential to understand the physiological and biochemical processes involved in bacterial communication. However, the current methods for AI-2 determination are complicated, time-consuming, and require costly equipment, such as a mass spectrometer (MS) or fluorescence detector (FLD). In this study, we present a new and easily applicable method for AI-2 determination. This method, based on the primary derivatization of AI-2 with 2,3-diaminonaphthalene (DAN), uses an affordable high-performance liquid chromatography (HPLC) instrument with a UV detector. Under optimized conditions, our method showed a good linearity (r2 = 0.999) and demonstrated the effective detection of AI-2 levels in various environmental samples, as follows: 0.38 (±0.05) μM for E. coli K12, 0.48 (±0.05) μM for Aeromonas sp. YB-2, 0.32 (±0.06) μM for the Enterobacter sp. YB-3, and 0.28 (±0.16) μM for activated sludge. [ABSTRACT FROM AUTHOR]

Here, two important isoflavones present in Trifolium pratense, formononetin and biochanin A, were analyzed by high performance liquid chromatography coupled with UV (HPLC–UV). These isoflavones are marker compounds with anti-inflammatory, anti-cancer, and anti-oxidant properties, and are also potent phytoestrogens that can be used in hormonal therapies. Till date, no study regarding rapid identification and quantification of T. pratense extract has been conducted. This study developed and validated an optimized method for quantifying formononetin and biochanin A using HPLC–UV. The results showed excellent linearity of the calibration curve (r2 ≥ 0.999), and good resolutions of chromatographic peaks were obtained. Other validation parameters such as specificity, accuracy, and precision demonstrated that our method had good reliability and sensitivity. Furthermore, our method for quantifying formononetin and biochanin A in T. pratense extract is convenient. [ABSTRACT FROM AUTHOR]

The current article is focused on introduction and validation of electro‐membrane extraction along with a high‐performance liquid chromatography combined with UV detector for the identification of the antiepileptic drugs phenytoin (PT) and phenobarbital (PB) in plasma, saliva, and urine. In addition, 3D‐printing was utilized to fabricate the designed caps required for fixing the electrodes in the prepared setup, giving us a high potential in device fabrication with various dimensions. To arrive at the highest extraction of PB and PT, the parameters impacting the extraction efficiency of electromembrane extraction for example, supported liquid membrane composition, sample solution pH, applied voltage, extraction time along with effect of graphene oxide are examined in detail. In optimized experimental conditions, the calibration plots were obtained to be linear on the concentration range of 25–500 ng/L with the detection limit and quantitation limit of 7.5 and 25 ng/L for both of PB and PT. Relative standard deviations of <9.9% and <9.1% were found for PB and PT, respectively and the enrichment factor for the presented method was computed to be 25.4 and 44.7 for PB and PT, respectively. The proposed method was satisfactorily employed in determination of PB and PT in plasma, urine and saliva. [ABSTRACT FROM AUTHOR]

This work presents the theoretical design, synthesis, characterization and application of a magnetic molecularly imprinted polymer (Mag-MIP) to quantify cortisol, the main stress biomarker, in urine samples. Density functional theory was used to predict a suitable solvent (acetonitrile) and a functional monomer (methacrylic acid) for MIP synthesis. Under these conditions, the Mag-MIP material was obtained by surface polymerization of modified Fe3O4 nanoparticles synthesized via the polyol method. The materials were characterized by scanning/transmission electron microscopy, infrared spectroscopy, vibrating sample magnetometry and thermogravimetric and Brunauer–Emmett–Teller surface analyses. Additionally, the Mag-MIP binding experiments showed rapid cortisol adsorption (completed in 20 min), Langmuir–Freundlich isotherm and a pseudo-first-order kinetic equation behaviour, and an excellent maximum binding capacity (200 µg g−1). The results were compared to those obtained for the magnetic non-imprinted polymer (Mag-NIP) and showed superior Mag-MIP performance. Selectivity experiments indicated that the Mag-MIP is capable of efficiently capturing cortisol in the presence of potential interfering substances. The Mag-MIP material was then applied to rapid quantitative cortisol extraction from urine samples prior to high-performance liquid chromatography with ultraviolet detection (limit of detection of 4 µg L−1 and recoveries ranging between 92 and 100%). Therefore, the proposed method might be readily implemented for routine non-invasive monitoring of human stress levels and other cortisol-related conditions. [ABSTRACT FROM AUTHOR]

In this paper, a green proline choline ionic liquid ([Ch][Pro])-modified magnetic graphene oxide was used as the solid-phase extractant (Fe3O4@SiO2@GO@[Ch][Pro]), which was characterized by FIR and hysteresis loops. A novel method for the determination of fenthion by magnetic solid-phase extraction with HPLC was established. Factors affecting extraction and elution performance were investigated, such as the amount of extractant, pH of the solution, the time and temperature of extraction and elution. Under the best conditions, a good linearity (R2 = 0.9987) equation was obtained with the concentration range 0.02–10 μg mL−1. This method has been successfully applied to the determination of fenthion in apple samples and water samples. [ABSTRACT FROM AUTHOR]

Aim of this work was to develop the first simple, rapid, green, economical and selective HPLC method for simultaneous quantification of the cited drugs in their challenging binary mixture. The work was motivated by the global trends towards sustainable chemistry in designing eco-friendly mobile system without affecting the analysis parameters. The proposed method was subjected to a greenness profiles using some metrics as Eco-scale. Materials and methods. This was accomplished under the following chromatographic conditions: HPLC column Discovery C18 (4.6 mm i.d. × 150 mm, 5 μm), column temperature 30 °C, flow rate 1.0 mL/min, mobile phase composed of 20% acetonitrile, 80% of 0.16% ammonium acetate and 0.2% of 1.5 M tetramethylammonium hydroxide (V/V) and signal monitoring at a wavelength of 225 nm and 237 nm. Results. A conventional mixture of acetonitrile and 0.16% ammonium acetate was tried in different ratios, but the drugs were not well separated. The shortest aliphatic chain cationic ion pair reagent tetramethylammonium hydroxide should not be exchanged with other type similar with this, like tetramethylammonium hydrogen sulfate, it did not work to our experiments. Increasing salt concentration, ammonium acetate, more than 0.2%, pushes the peak of atenolol closer to dead volume, which is negative. Atenolol in their methods for multicomponent mixtures elutes in dead volume, or when retained longer, much stronger, hydrophobic mobile phase should be used if valsartan should be seen in same chromatogram at dissent time. The 237 nm can be chosen as compromise signal for nearly equal peaks height with high sensitivity is not essential. The 225 nm signal shows much higher sensitivity for atenolol and less increase for valsartan peaks, which can be used when higher sensitivities will be essential. Linearity was examined and proven at different concentration levels in the range of working concentration of valsartan (0.16–0.96 mg/mL) and atenolol (0.2–1.20 mg/mL). The high value of recoveries obtained for valsartan and atenolol indicates that the proposed method was found to be accurate. The results of proposed method found to be an excellent green analysis with a score of 84. Conclusion. A new fast, simple and green, but selective, accurate, precise and robust HPLC-UV method for simultaneous determination of valsartan and atenolol in newly formulated dosage form was developed and many possible variations of the same were suggested. The developed method for the simultaneous quantification of valsartan and atenolol in their challenging binary mixture offers simplicity essential for quality control of a large number of samples in short time intervals, which is necessary for routine analysis. The method was subjected to greenness profile assessment. [ABSTRACT FROM AUTHOR]

Aim. We aimed to develop and validate fast, simple, accurate, robust and rugged chromatographic method for simultaneous determination of bisoprolol fumarate and enalaril maleate in solid pharmaceutical dosage form, with using chaotropic strong chaotropic perchlorate anions in composition of mobile phase. Materials and methods. Fast simple HPLC method for simultaneous determination of bisoprolol and enalapril in solid pharmaceutical dosage forms was developed, with perfect peak symmetries eluting at 4.7 and 5.2 miutes, with mobile phase composed of methanol and diluted perchloric acid pumped with 1ml/min on Zorbax Rx C8 250x4.6mm, 5um column thermostated at 42 °C, and monitored UV signal at 214nm. Mobile phase was composed of 55%methanol and 45% perchloric acid (0.07%v/v). Results. Usage of presence of perchloric anions showed very useful role in peak shape and chromatogram view, due to distinguished chaotropic characteristics of perchlorate anions on molecules containing nitrogen atoms in molecular structures of analytes, in acidic pH environment. Linearity was examined and proven at different concentration levels in the range of working concentration of bisoprolol (20–200 ug/ml) and enalapril (20–200 ug/ml). The methods achieved very good validation parameters, with determined LOQ about 0.032 mg/ml and LOD about 0.003 mg/ml for bisoprolol, and LOQ about 0.045 mg/ml and LOD 0.005 mg/ml for enalapril. The high value of recoveries obtained for bisoprolol and enalapril indicates that the proposed method was found to be accurate. Conclusion. A new fast and simple, but selective, accurate, precise and robust HPLC method for simultaneous determination of bisoprolol and enalapril in tablets was developed and many possible variations of the same were suggested. The developed method for the simultaneous quantification of bisoprolol and enalapril from solid dosage formulations offers simplicity essential for quality control of a large number of samples in short time intervals, which is necessary for routine analysis. [ABSTRACT FROM AUTHOR]