High-performance Liquid Chromatographic Method Research Articles

A Validated Chiral Chromatography Method for Enantiomeric Separation of Pomalidomide in Human Plasma.

In the present work, new chiral stationary phase high-performance liquid chromatography (CSP-HPLC) method was established and validated for the quantification of pomalidomide (PMD) enantiomers in human plasma. The chromatographic enantiomeric separation was achieved on a Daicel-CSP, Chiralpack IA 4.6 × 250mm, 5μm; because of its advantages of high degree of retention, high resolution capacity, better reproducibility, ability to produce lower back pressure and low degree of tailing. The mobile phase was maintained as methanol: glacial acetic acid (499.50ml:50μL). Ultraviolet wavelength for detection was 220nm. PMD enantiomer-I and enantiomer-II were separated at 8.83 and 15.34min, respectively. Limit of detection and limit of quantification for each enantiomer and the calibration curve of standard PMD was linear in range between 10-5,000ngmL-1. The method was validated according to The International Council for Harmonisation of Technical Requirements of Pharmaceuticals for Human Use (ICH(Q2R1)) specific guidelines. We found no interference peak with PMD chromatogram obtained. This is a simple, reliable and specific method for detection and quantification of enantiomer of PMD in human plasma sample.

Novel Alaninamide Derivatives with Drug-like Potential for Development as Antiseizure and Antinociceptive Therapies─In Vitro and In Vivo Characterization.

In the present study, a series of original alaninamide derivatives have been designed applying a combinatorial chemistry approach, synthesized, and characterized in the in vivo and in vitro assays. The obtained molecules showed potent and broad-spectrum activity in basic seizure models, namely, the maximal electroshock (MES) test, the 6 Hz (32 mA) seizure model, and notably, the 6 Hz (44 mA) model of pharmacoresistant seizures. Most potent compounds 26 and 28 displayed the following pharmacological values: ED50 = 64.3 mg/kg (MES), ED50 = 15.6 mg/kg (6 Hz, 32 mA), ED50 = 29.9 mg/kg (6 Hz, 44 mA), and ED50 = 34.9 mg/kg (MES), ED50 = 12.1 mg/kg (6 Hz, 32 mA), ED50 = 29.5 mg/kg (6 Hz, 44 mA), respectively. Additionally, 26 and 28 were effective in the ivPTZ seizure threshold test and had no influence on the grip strength. Moreover, lead compound 28 was tested in the PTZ-induced kindling model, and then, its influence on glutamate and GABA levels in the hippocampus and cortex was evaluated by the high-performance liquid chromatography (HPLC) method. In addition, 28 revealed potent efficacy in formalin-induced tonic pain, capsaicin-induced pain, and oxaliplatin- and streptozotocin-induced peripheral neuropathy. Pharmacokinetic studies and in vitro ADME-Tox data proved favorable drug-like properties of 28. The patch-clamp recordings in rat cortical neurons showed that 28 at a concentration of 10 μM significantly inhibited fast sodium currents. Therefore, 28 seems to be an interesting candidate for future preclinical development in epilepsy and pain indications.

Experimental design approach for the quantitative analysis of multicomponents by single marker and HPLC fingerprinting of Thunbergia laurifolia aqueous extract.

Thunbergia laurifolia is used in traditional Thai medicine to reduce fever and treat mouth ulcers. However, the quantitative analysis of chemical markers has not yet been officially defined. The objective of this study is to develop a high-performance liquid chromatography (HPLC) method using a design of experiment (DoE) for the quantitative analysis of multicomponents by single marker (QAMS) and fingerprinting of the T. laurifolia aqueous extract. Critical variables were screened using a two-level fractional factorial design, followed by the optimization of the selected variables using a central composite design. The validated method was applied for quality assessment based on QAMS and fingerprinting of the extract. Optimum conditions of DoE for the analysis of caffeic acid, vicenin-2, and rosmarinic acid were determined. The relative correction factors for caffeic acid and vicenin-2 were calculated using rosmarinic acid as an internal reference standard, and their contents in 30 samples were determined. The differences between the external standard method (ESM) and QAMS were compared. No significant difference was observed in the quantitative determination, proving the consistency QAMS and ESM. HPLC fingerprints of T. laurifolia were established with 8 of 12 characteristic peaks that were structurally characterized using HPLC-diode array detection-electrospray ionization/tandem mass spectrometry. The similarity of the fingerprints in all samples was ≥0.74, and the pattern recognition of the characteristic peaks was satisfied. The proposed method efficiently detected multiple components of the T. laurifolia extract. Thus, the method is beneficial in providing references for enhancing the quality control of other herbal medicines.

Stability-Indicating HPLC Method for Determination of Ibuprofen and Famotidine Degradation Products.

A new stability-indicating high-performance liquid chromatographic method for the quantitative determination of ibuprofen and famotidine degradation products in combined pharmaceutical products was developed and validated. The current aim of this study is to develop a rapid, accurate and robust analytical stability indicating impurity method that can separate ibuprofen, famotidine and their related impurities by using a reversed-phase high-performance liquid chromatography. A Zorbax SB-Phenyl column (4.6 × 150mm2, 5-μm particle size) with mobile phase containing phosphate buffer solution with a pH value of 3.0 and acetonitrile was used. The flow rate was 0.8mL/min and the analytes were detected by UV detector at 265nm. The retention times of ibuprofen and famotidine were 18.43 and 5.14min, respectively. This method was validated to confirm specificity, linearity, sensitivity (limit of detection and limit of quantitation), precision, accuracy, robustness and sample stability according to the International Conference on Harmonization guidelines. Studies have been completed and reported with two active substances in the combined dosage form and seven impurities in total. There is no method in the literature that simultaneously distinguishes and quantitatively analyzes both active substances and degradation products.

Molecularly imprinted polymers using high-performance liquid chromatography to detect and determine ethion pesticide in apricot, grapes, strawberry and soil samples

ABSTRACT This paper demonstrates the synthesis of molecularly imprinted polymers-solid phase extraction-liquid chromatography method at room temperature using bulk polymerisation of ethion pesticide, by high sensitivity, low costs and high stability. By making MIP for ethion as ethion-MIP, which could be detected with a UV-Vis spectrophotometer at 276 nm, a functional monomer of acrylic acid with cross-linking ethylene glycol dimethyl acrylate. The high-performance liquid chromatography methods developed in this study are accurate, sensitive, and precise to apricot, grapes, strawberry and soil samples. The elution process to the template ethion from the ethion-MIP, caused by minimum volume using solution of 1.0 mL of methanol-acetic acid (9:1) was obtained. Different factors affecting the reaction were studied and optimised. The calibration plot is linear in the concentration range of (0.02 to 1.0 µg mL−1). The relative standard deviations of (±2.0%) and detection limit of the method are 0.02 µg mL−1, and the maximum imprinting factor of ethion-MIP was 6.8 mgg−1. The results obtained the evidence of efficiency and reliability of the method for the ethion pesticide analysis and estimation for the capacitance of molecular imprinted polymer, analytical technical method by molecularly imprinted polymer and high-performance liquid chromatography.

Comparison of Glycated Hemoglobin (Hba1c%) between High Performance Liquid Chromatography (HPLC) and Non-HPLC Methodology

Background: Glycated hemoglobin (HbA1c) serves as a pivotal marker for the long-term management of glucose levels in patients with diabetes. Accurate measurement of HbA1c is crucial for effective diabetes management and prevention of associated complications. While High-Performance Liquid Chromatography (HPLC) is widely used, non-HPLC methods have also gained popularity due to their simplicity and cost-effectiveness. Discrepancies in measurement between these methods have been a concern, impacting clinical decisions. Objective: The objective of this study was to compare the measurement of HbA1c% using HPLC and non-HPLC methods in a cohort of diabetic patients, evaluating the consistency and reliability of these methodologies. Methods: A cross-sectional study was conducted at Hayatabad Medical Complex, MTI, Peshawar from November 2023 to March 2024. A total of 65 diabetic patients aged between 18 and 70 years were enrolled. Participants were excluded if they had conditions known to affect HbA1c measurement. HbA1c levels were measured using both HPLC and non-HPLC methods. Statistical analysis was performed using SPSS version 25, employing t-tests to compare the mean HbA1c levels and Bland-Altman analysis to assess agreement between the two methods. Results: The HPLC method showed a mean HbA1c% of 8.2 (SD = 1.4) while the non-HPLC method showed a mean HbA1c% of 7.6 (SD = 1.3). The Bland-Altman analysis indicated that 91.5% of the values fell within the limits of agreement, suggesting substantial agreement between the methods. The mean difference in HbA1c% between methods was 0.6%, with limits of agreement from -0.3 to 1.5. Conclusion: Both HPLC and non-HPLC methods provided reliable HbA1c measurements, with a high degree of agreement. Despite minor discrepancies in mean values, both methodologies are suitable for the clinical monitoring of glycemic control in diabetic patients. Further studies with larger sample sizes and multiple centers are recommended to validate these findings.

THE PROBLEM OF REGULATING FUNGICIDES ON THE SKIN SURFACE FOR OCCUPATIONAL SKIN DISEASE IN AGRICULTURAL WORKERS’ RISK PREDICTION

The aim. To establish the norms of fungicides on the skin surface and predicting the risk of occupational skin pathology in agricultural workers to develop measures to prevent diseases caused by dermal exposure to pesticides. Materials and methods. The natural experiment was performed in accordance with modern requirements (European Food Safety Authority (2022), and the risk assessment was carried out according to the Recommendations (Approved by the Ministry of Health of Ukraine No. 324 issued on 13.05.2009) with different methods of spraying techniques: rod, air blast fan spraying, pre-sowing, aviation, knapsack treatment. 17 series of natural experiments were performed, and the air of the working zone area (n =56) and dermal exposure (n =56) were analyzed for each worker with different pesticide application methods. Quantitative determination of pesticide content was carried out by gas-liquid and high-performance liquid chromatography methods. The results were statistically processed using a package of licensed statistical programs MedStat v.5.2 (Copyright © 2003-2019) and Microsoft® Excel® for Microsoft 365 MSO. Results. It was established that there is pesticide contamination, mainly of the gloves of tank filling operators when preparing working solutions. No contamination of the skin surface was detected; only pesticide residues were present on the surface of the workers’ overalls. A comparison of the exposure dose in case of percutaneous exposure during the performance of technological operations with different methods of processing, dermal equivalents of Acceptable Operator Exposure Level of pesticide to workers’ skin (DE AOEL) and the allowable dermal dose for professional contingents (ADderm) and the hazard coefficients by dermal exposure (HCderm) showed that that dermal exposure during individual technological operations with different processing methods had a reliable difference between processing methods, but there is no difference within one application method. Conclusions. During the comparison of the hazard coefficients for dermal exposure, calculated according to different models, no significant difference was found between the risks calculated according to DE AOEL and ADderm for individual technological operations in various treatment methods, except for the operator who performed knapsack treatment and the risk calculated according to ADderm is significantly lower compared to the DE AOEL risk.

Validation of a simple bioanalytical method for the determination of melatonin concentration in human serum using high-performance liquid chromatography with a fluorescent detector

Analysis of melatonin in biological samples is a challenge for the analyst both because of its low concentration and because of the numerous interfering substances. Therefore, chromatography, as a powerful analytical technique used for the separation, detection, and quantification of analytes, can be the method of choice for determining melatonin in biological samples for clinical use and pharmacokinetic research. The method was developed and validated according to the internal documents in accordance with Good Laboratory Practice. The concentrations of melatonin in human serum were determined using a high-performance liquid chromatography method with a fluorescence detector and mirtazapine as an internal standard. Preparation of serum samples was performed by liquid–liquid extraction with ethyl acetate: n-hexane (1:1 v/v). High linearity was exhibited over a concentration range of 25–10,000 pg/mL of melatonin, with a correlation coefficient higher than 0.999 during the course of method validation. Repeatability and intermediate precision show a relative standard deviation lower than 6.6 %, and accuracies were from 90.7 % to 110.3 %. The lower limit of quantitation was 30 pg/mL, and the limit of detection was 7.92 pg/mL. The in-house method is simple, fast, reproducible, and applicable for the determination of melatonin in human serum.

Comprehensive analyses of phenylalanine hydroxylase variants and phenotypic characteristics of patients in the eastern region of Türkiye.

Phenylalanine hydroxylase (PAH) is predominantly a hepatic enzyme that catalyzes phenylalanine (Phe) into tyrosine, which is the rate-limiting step in Phe catabolism. Biallelic variants in the PAH gene cause PAH enzyme deficiency. Phenylketonuria (PKU) is an autosomal recessive disorder that causes neurologic, behavioral, and dermatological findings. PKU could be divided clinically into three types based on the blood Phe levels: classic phenylketonuria (cPKU), mild-moderate phenylketonuria (mPKU), and mild hyperphenylalaninemia (MHP). This study aimed to determine the phenotypic and genotypic characteristics of Turkish PKU patients in the eastern region of Türkiye. Demographic characteristics, serum Phe levels, treatments, and PAH variants of 163 patients with PKU and hyperphenylalaninemia (HPA) were retrospectively evaluated. Blood Phe levels of the patients were analyzed with the high-performance liquid chromatography method. For PAH gene analysis, next-generation sequencing was performed. Of the 163 patients included in the study, 38 (23.3 %) had cPKU, 16 (9.8 %) had mPKU, and 109 (66.9 %) had MHP. Homozygous variants in the PAH gene were detected in 66 (40.5 %) of the patients, while compound heterozygous variants were detected in 97 (59.5 %) patients. Two novel and 35 recurrent variants in the PAH gene were detected. Of the twonovel variants, one was missense (p.Phe351Leu) and the other was frameshift (p.Met276Cysfs*65). The most frequently detected variants were p.Thr380Met (18 %), p.Arg261Gln (16.8 %), and p.Ala300Ser (12.8 %). All patients with the homozygous c.1066-11G>A variant exhibited cPKU phenotype. The c.898G>T (p.Ala300Ser), c.1139C>T (p.Thr380Met), and c.1208C>T (p.Ala403Val) variants were statistically related to mild phenotype. On the other hand, c.592_613del (p.Tyr198Serfs*136), c.1028A>G (p.Tyr343Cys), and c.782G>A (p.Arg261Gln) variants were more frequently detected in the cPKU group. Our study, conducted with patients from the eastern region of Türkiye, demonstrates the genetic heterogeneity in the Turkish population. Simultaneously, our research contributes to genotype-phenotype correlation and expands the genotypic spectrum by identifying novel variants.

RP-HPLC METHOD DEVELOPMENT AND VALIDATION FOR SIMULTANEOUS ESTIMATION OF CURCUMIN AND RESVERATROL IN NANO-MICELLE: DUAL DRUG DUAL FORM SIMULTANEOUS ESTIMATION

Objective: To develop a reverse-phase high-performance liquid chromatography (RP-HPLC) method for simultaneous estimation of conjugated form of Curcumin (CCMN) and free form of Resveratrol (RSV) in nano-micelle. Methods: The conjugation of lipophilic CCMN and hydrophilic Chitosan (CHT) through succinyl linker produce amphipathic molecule that can self-assemble into RSV solution to form micelle. Here RSV exists in micelle core as free form and CCMN with micelle backbone as conjugated form. So it required to estimate conjugated drug and free drug simultaneously from nano-micelle. We developed a RP-HPLC method, utilized C18 column, follow flow rate of mobile phase 1.0 ml/min, which consist of acetonitrile with water (0.5% Ortho Phosphoric acid, pH 4.6) in the ratio of 1:1 for 20 min. Injection volume was 10μl and column temperature 25 ℃. Isosbestic detection of both drugs was at 254 nm. Results: The retention time of RSV and CCMN were at 8.15 min and 11.41 min respectively, completely distinguished sharp peak of CCMN and RSV developed with resolution 7.360±0.117, wide range of linearity with correlation coefficient value (R2) of CCMN and RSV were 0.99987 and 0.99992 respectively and recovery value of CCMN and RSV were 100.041±0.22 % and 100.041±0.21 % respectively. The RSD (relative standard deviation) for accuracy, precision and robustness of the method was found to be less than 2%. Conclusion: The develop method for simultaneous estimation of conjugated CCMN and free form of RSV in the nano-micelle formulation was consider to be accurate, precise, robust and sensitive.

Drug synthesis, separation, and identification of a di-stereoisomeric mixture of spiro-oxalidinonic derivatives of sorbinil by high-performance liquid chromatography

A straightforward and sensitive method for high-performance liquid chromatography (HPLC) was created in order to separate and identify the di-stereoisomeric mixture of a spiro-oxalidinonic derivative of sorbinil. HPLC was carried out using a C18 reversed-phase column. The mobile phase used in the isocratic elution process was a 70:30 v/v combi¬nation of methanol and acetonitrile flowed at a rate of 2 mL/min. The procedure delivered the best result among the various attempts made. Two peaks were identified on the chromatogram, attributable to the two di-stereoisomers of the mixture analysed. Analogues of sorbinil, a powerful inhibitor of aldose reductase, have been synthesized and further tested on aldose reductase as mixtures of di-stereoisomers, exhibiting an IC50 in the order of the micromolar. The structure of the compounds was checked with nuclear magnetic resonance spectroscopy. The chemical shifts were expressed in ppm scale δ.

Development of Response Surface Approach for Determination of Paracetamol, Chlorpheniramine Maleate, Caffeine and Ascorbic Acid by Green HPLC Method: A Desirability-Based Optimization.

Design of experiment is an efficient and cost-effective tool to optimize the chromatographic separation of a multicomponent mixture. The central composite design was conducted to develop and optimize a green high performance liquid chromatography (HPLC) method for simultaneous quantitation of a quaternary mixture of paracetamol, chlorpheniramine maleate, caffeine and ascorbic acid in their pharmaceutical dosage form as well as the determination of their dissolution profile. A five-level three-factor model was performed to investigate the effect of mobile phase composition, pH and flow rate on enhanced resolution and short run time. Analysis was performed using a Kinitex EVO C18 column and a mobile phase composed of methanol: 0.02M phosphate buffer pH3.3 (34:66, v/v) at 1.0mL/min using photodiode array detection. Optimum chromatographic separation was achieved in <6min with a desirability of 0.999. Linearity was achieved over a range of 1.00-300.00, 1.00-50.00, 2.00-50.00 and 2.00-100.00μg/mL for paracetamol, chlorpheniramine maleate, caffeine and ascorbic acid, respectively, with a limit of detection (<0.1μg/mL). The greenness profile was evaluated using the analytical eco-scale and Analytical GREEnness Metric Approach with values of 81 and 0.77, respectively.

Linear solvent strength model on porous graphitic carbon stationary phase using high temperature liquid chromatographic method for allopurinol related substances analysis

A high-performance liquid chromatography (HPLC) method was developed for the analysis of Allopurinol and its Ph.Eur. impurities using a porous graphitic carbon (PGC) stationary phase. Retention behavior of solutes was studied across a wide temperature range (30–90 °C) and various gradient times (5–20 min). Analysis of the data revealed distinct retention mechanisms between reversed-phase and PGC phases. However, it was proved that the retention of Allopurinol and its Ph.Eur. impurities on PGC stationary phase can be effectively modeled using the linear solvent strength (LSS) theory. This allows for the utilization of LSS-based method development software to optimize methods under these conditions. By using commercial chromatographic modeling software, separation of Allopurinol and Ph.Eur. impurities was optimized within a large design space. At the optimized operating conditions (pH = 2.0, tG = 6 min, T = 60 °C), all solutes were separated within 6 min with baseline resolution. Comparison between predicted and experimentally measured chromatograms further confirmed the applicability of LSS theory in developing analytical methods for PGC-based HPLC systems. The presented approach offers a general framework for method development on PGC phases.

Development and Validation of the HPLC Method for Simultaneous Quantification of Glucose and Xylose in Sugar Cane Bagasse Extract.

A validated rapid high-performance liquid chromatography (HPLC)-refractive index (RI) method was developed for the identification and quantification of glucose and xylose in hydrolyzed bagasse extract. The separation of compounds was achieved on Eurokat® H column (300 × 8mm, 10μm) at 75°C, using 0.01N sulfuric acid solution as mobile phase and 0.6mL/min as flow rate. The method was validated based on accuracy, precision, linearity, robustness, uncertainty, limit of detection (LOD) and limit of quantification (LOQ). Total chromatographic analysis time per sample was ~11min. Calibration plots were linear over the concentration ranges 11-100μg/100μL for glucose and xylose. The LOD was 0.8ppm and LOQ was 2.5ppm. The high recovery and low relative standard deviation confirm the suitability of the method for determination of glucose and xylose in bagasse extract. The proposed HPLC-RI method was accurate, fast and robust and required less run time due to less analytes retention times and allowed optimal energy consumption owing to lower column oven temperature.

Vancomycin bioanalysis for TDM services by using immunoassay and HPLC: A scoping review

Background: Administration of vancomycin in treating infections caused by Methicillin-resistant Staphylococcus aureus (MRSA) requires therapeutic drug monitoring (TDM). The immunoassay method and high-performance liquid chromatography (HPLC) are the two methods of choice for examining vancomycin levels, with their respective advantages. Objective: This study aims to review the validity of immunoassay and HPLC methods, as well as consider which method is appropriate, effective, and efficient for TDM in the clinical setting. Method: Related articles were searched for using the keywords "immunoassay", "vancomycin", "HPLC", "bioanalysis", and "human" in the PubMed, Google Scholar, and Science Direct databases. Result: A total of 20 publications examined immunoassays, whereas 23 articles covered HPLC. Both the immunoassay and HPLC methods provided acceptable bioanalytical validation values. Conclusion: The immunoassay method is an option for routine sample analysis that requires fast results, but this method is not recommended for patients with high immunoglobulin levels. The HPLC method is a choice because it offers better selectivity and sensitivity.

Identification of major degradation products of Clorsulon drug substance including its degradation pathways by high resolution mass spectrometry and NMR

Clorsulon is an effective anthelmintic drug substance extensively used in the treatment of parasitic infestations in both cattle and sheep. An in-depth investigation of Clorsulon’s degradation products (DPs) was carried out through forced degradation study to comprehend its degradation path. A total of eight degradation products were separated under various stress degradation conditions. Structural elucidation of these DPs was conducted using ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS), and their fragmentation patterns were compared to that of the parent compound. Adequate amount of DP-4 was isolated and purified by semi-preparative high-performance liquid chromatography (HPLC) methods. Subsequently, it was examined in detail using both 1D and 2D NMR (nuclear magnetic resonance spectroscopy). Most probable mechanistic pathways for the formation of degradation products under various stress degradation conditions were proposed to better understand the degradation profile. Based on the results of the stress study, Clorsulon drug substance was found to be unstable under photolytic and oxidative conditions. Understanding Clorsulon's degradation pathway is essential for determining shelf-life prediction of finished product, safety and efficacy assurance, and guiding the development of stable, high-quality formulations.

Therapeutic effects of lincomycin and level of drug degradation in broiler tissues after treatment

Background and Aim: Lincomycin is an antibiotic used in broiler farming and is commonly combined with other substances to achieve synergistic and complementary effects on the antibacterial spectrum and mechanism. We developed a specific high-performance liquid chromatography (HPLC) method to measure lincomycin levels in broiler tissues. This study aimed to determine the lincomycin level in tissues and compare it with the minimum inhibitory concentration (MIC) and maximum residue limit (MRL) of certain pathogenic bacteria. Materials and Methods: Three groups of broiler chickens were involved in the study (n = 20 in each group): A control group without lincomycin treatment and two groups (each further divided into two sub-groups) that received oral lincomycin at a dose of 1 g/10 kg of body weight daily for 7 and 14 consecutive days. Tissue samples were collected from each group 1 day and 1 week after lincomycin administration (ALA). This study validated the development of a technique for analyzing drug level degradation in tissues using HPLC. Descriptive and statistical analyses were performed for drug levels to assess their therapeutic value and safety based on lincomycin MIC of certain pathogenic bacteria and MRL. Results: The method validation resulted in linear regression and coefficient of determination for tissues with r2 &gt; 0.99, with a recovery rate of 90%–110%, precision as the coefficient of variation 15%, and specificity with no peak overlap for lincomycin. The limits of detection for the liver and kidney were 0.01 μg/g, 0.05 μg/g, and 0.1 μg/g for the breast muscle and all tissues. Administration of lincomycin for 7 and 14 days resulted in therapeutic value concentrations. Lincomycin levels in the liver and kidney of ALA exceeded the MRL, whereas breast muscles were below the MRL for a week of ALA treatment. Conclusion: Administration of lincomycin for 7 and 14 consecutive days resulted in therapeutic value; however, after a week, most tissues showed high drug concentrations that exceeded the MRL. It is necessary to carefully consider the prolonged therapeutic dose of lincomycin in broilers. Antibiotic therapy must be guided in such a way as to protect the product from harmful residues. Keywords: : broiler tissues, lincomycin level, maximum residue limit, minimum inhibitory concentration.

Performance evaluation and validation of high-performance liquid chromatography method for the quantification vitamins A and E

Performance evaluation and validation of high-performance liquid chromatography method for the quantification vitamins A and E

Fabrication of an electrochemical sensing platform based on MWCNT-CONH-66-UiO and PEDOT:PSS for highly sensitive and rapid detection of sunset yellow

The out-of-range, overdose and illegal usage of sunset yellow azo dye in food will cause great damage to food safety and consumer health. In this work, a novel electrochemical sensing platform toward sunset yellow detection was prepared based on the amidated MWCNT-CONH-66-UiO and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). In MWCNT-CONH-66-UiO, the –NHCO- is produced by the amidation reaction between zirconium 2-amino terephthalate (UiO-66-NH2) and carbonylated multi-walled carbon nanotubes (MWCNT-COOH), which play significant role for the enhancement of the sensing properties of MWCNT-CONH-66-UiO/PEDOT:PSS composite. PEDOT:PSS acts as a conducting film coated on MWCNT-CONH-66-UiO and alleviates the electrooxidation of –NHCO-. The large specific surface area, good conductivity, and outstanding synergistic effect of the composite trigger off prominent sensing properties of MWCNT-CONH-66-UiO/PEDOT:PSS toward sunset yellow detection with the lowest detection limit as 3.3 nM and a sensitivity as 6.6 mA mM−1 cm−2 (active area of 0.15 cm2). Additionally, this sensor shows satisfactory results for sunset yellow detection in plain cake and marinating meat via DPV in comparison to the high-performance liquid chromatography method. The research results in this work will provide technical support for the rapid and efficient detection of azo dyes in food, animal feeds, and industrial wastewater.

Validated Stability Indicating UHPLC Method for the Quantification of Escitalopram and Flupentixol in Pharmaceutical Formulation

To assess Escitalopram and flupentixol simultaneously, a verified method for ultra-phase high-performance liquid chromatography (UHPLC) has been developed to indicate stability. The method was thoroughly evaluated and met satisfactory criteria for precision, linearity, accuracy, limits on detection, robustness, and quantitation. The quantitation wavelength of 235 nm was determined. Linearity was successfully demonstrated across concentration ranges of 1–5 µg/ml of Escitalopram and 20-100 µg/ml of Flupentixol. UHPLC separations were conducted employing a Phenomenex L. C18 column measuring 100 x 4.6 mm and containing particles as small as 2.5 µm. To create the mobile phase, the 1% OPA and methanol (a pH of 4.2 with TEA) were combined in a volumetric ratio of 65:35v/v. Escitalopram and Flupentixol were effectively eluted at retention durations of 3.044 and 4.118 minutes, respectively, with the flow rate adjusted at 1.0 ml. The stability-indicating nature of the method was established through validated forced degradation studies. Which included hydrolysis under acidic and basic conditions, exposure to H2O2, thermal degradation, and photo-degradation. Escitalopram and Flupentixol exhibited 10 to 20% degradation under the specified conditions. Importantly, the process evaluated the two prescription drugs in detail with all degradation products generated during the forced degradation experiments. This developed method is characterized as straightforward, specific, and cost-effective, making it suitable for simultaneous estimating Escitalopram and Flupentixol in tabs dose forms.