Method For Simultaneous Determination Research Articles

Development and application of a LC-HRMS method for simultaneous determination of ten illicit antifungal drugs in herbal bacteriostatic products.

The widespread use of sub-therapeutic antibiotics may lead to treatment failures, increased resistance to antibiotics, and even the encouragement of the formation of superbugs. Fraudulent herbal medicines that actually contain unlabeled active ingredients are a global problem. Therefore, streamlined and accurate analytical techniques that can identify and quantify a variety of antimicrobials in suspected illegal products are required. In the present work, we developed a sensitive, robust, and accurate method that involves multi-step extraction, EMR-lipid-based pass-through cleanup, and UHPLC-Q/HRMS with an orbital ion trap instrument analysis for the simultaneous detection of ten illicit antifungal drugs (flucytosine, fluconazole, ketoconazole, naftifine hydrochloride, griseofulvin, bifonazole, econazole nitrate, elubiol, clotrimazole, and miconazole nitrate) in herbal disinfection products. This validated method was then applied to 210 authentic samples, resulting in 25% of the samples being positive for the drugs. The results suggested the need to strengthen controls in this field to detect illicit antifungal drugs in herbal bacteriostatic products, which represents a potential health risk for the consumer. On a global scale, more and more frequent routine monitoring is being carried out in this area. This study provides valuable insights into large-scale complex sample chemical profiling, and the method developed appears to be promising and applicable for high-throughput routine multiple antibiotic analysis in a complex sample matrix.

A simple analytical method for simultaneous determination of currently used pesticide (CUP) residue in river water using LC-MS/MS

A simple analytical method for simultaneous determination of currently used pesticide (CUP) residue in river water using LC-MS/MS

A fluorescence immunochromatography method for detection of human papillomavirus type 16 E6 and L1 proteins

This study aims to establish a time-resolved fluorescence immunochromatography method for simultaneous determination of human papillomavirus (HPV) type 16 E6 and L1 protein concentrations. The amount of lanthanide microsphere-labeled antibodies, the concentration of coated antibodies, and the reaction time were optimized, and then a test strip for the simultaneous determination of the protein concentrations was prepared. The performance of the detection method was evaluated based on the concordance of the results from clinical practice. The optimal conditions were 8 μg and 10 μg of HPV16 L1 and E6-labeled antibodies, respectively, 1.5 mg/mL coated antibodies, and reaction for 10 min. The detection with the established method for L1 and E6 proteins showed the linear ranges of 5-320 ng/mL and 2-64 ng/mL and the lowest limits of detection of 1.78 ng/mL and 1.09 ng/mL, respectively. There was no cross reaction with human immunodeficiency virus (HIV), treponema pallidum (TP), or HPV18 E6 and L1 proteins. The average recovery rate of the established method was between 97% and 107%. The test strip prepared in this study showed the sensitivity, specificity, and diagnostic accuracy of 97.46%, 90.57%, and 95.32%, respectively, in distinguishing patients with cervical cancer and precancerous lesions from healthy subjects, with the area under the curve (AUC) of 0.980 1 and 95% Confidence Interval (CI) of 0.956 5 to 1.000 0. The time-resolved fluorescence immunochromatography combined with the test strips prepared in this study showed high sensitivity, high accuracy, simple operation, and rapid reaction in the quantitation of HPV16 E6 and L1 proteins. It thus can be used as an auxiliary method for the diagnosis and early screening of cervical cancer and precancerous lesions and the assessment of disease course.

Paralytic Shellfish Poisoning (PSP) Toxins in Bivalve Molluscs from Southern Italy Analysed by Liquid Chromatography Coupled with High-Resolution Mass Spectrometry (UHPLC-HRMS/MS).

A new method for simultaneous determination by liquid chromatography coupled with high resolution mass spectrometry (UHPLC-HRMS/MS) of 14 paralytic shellfish poisoning toxins (PSP), that is, Saxitoxin, Neosaxitoxin, Gonyautoxins and their respective variants, in bivalve molluscs, is herein described. The samples were extracted by acetic acid solution, then analysed by UHPLC coupled with a Q-Exactive Orbitrap Plus high resolution mass spectrometer, by electrospray ionization mode (ESI) with no further clean up step. The analysis was carried out by monitoring both the exact mass of the molecular precursor ion of each compound (in mass scan mode, resolution at 70,000 FWHM) and its respective fragmentation patterns (two product ions) with mass accuracy greater than 5 ppm. The analytical performance of the method was evaluated calculating trueness, as mean recoveries of each biotoxin, between 77.8% and 111.9%, a within-laboratory reproducibility (RSDR) between 3.6% and 12.2%, the specificity, the linearity of detector response, and the ruggedness for slight changes The results of the validation study demonstrate this method fits for the purposes of the official control of PSP toxins in molluscs. The results of two years of monitoring in local mussel farms are also reported, showing that no significant concerns for food safety in the monitored productions.

Comparison of electronic apex locator and simultaneous working length detection methods with radiological method in terms of postoperative pain

BackgroundPrecise knowledge of the apical construction, which determines the end of the area for canal preparation and filling, is essential for the success of root canal treatment and the management of postoperative pain. For this purpose, devices based on various methods that determine the working length (WL) are used. However, it is still controversial which method provides the most accurate measurements.AimTo investigate the compatibility of the electronic apex locator (EWL) and simultaneous working length determination (SWL) methods in single-root teeth in comparison with the radiographic working length determination (RWL) method and to determine which one produced more effective results in terms of postoperative pain.Materials & methodsOne hundred patients scheduled for root canal treatment (RCT) were randomly assigned to one of the three groups according to the working length measurement method (EWL, SWL or RWL). After WL determination with assigned method, root canals were prepared and then obturated. Age, gender, simplified oral hygiene index (OHI-S), oral and dental examinations and Visual Analogue Scale (VAS) results of all participants were recorded. The incidence and intensity of postoperative pain were rated on a Visual Analogue Scale (VAS) by patients 6, 12, 24, 48 h and 7 days after RCT. The number of analgesic tablets (400 mg Ibuprofen) taken by patients was also recorded. Data were analyzed using the chi-square, One- way ANOVA and Kruskal-Wallis tests. Bland-Altman and Passing-Bablock regression analysis were used as method comparison techniques.ResultsIt was determined that the number of patients receiving analgesia and the total number of analgesia doses were higher in EWL and RWL groups compared to SWL group (p < 0.0001). When the WL values at which the treatment was applied were compared in the patient groups; WL values of EWL group were statistically lower than SWL group (p < 0.01). While there was no difference between the preoperative VAS scores of the groups (p = 0.7590), the postoperative 6th and 12th hour VAS scores of SWL group were lower than those of EWL and RWL groups (p = 0.005 and p = 0.0002, respectively). Again, the VAS scores of SWL group at the 24th and 48th postoperative hours were lower than those of RWL group (p < 0.05). According to the Bland-Altman and Passing-Bablock regression analysis results, although there was no statistically significant difference between the EWL and SWL methods (p = 0.471), the bias value of -0.1190 was well below the acceptable total error (0.1648). Additionally, a strong relationship was found between EWL and SWL methods (r = 0.9698, r2 = 0.9406, p < 0.001). Therefore, statistically these two methods were considered compatible with each other. It was determined that there was a statistically significant bias (0.340, p < 0.0001) between the RWL and SWL methods, exceeding the total error.ConclusionsAs a result, it was determined that the SWL method, which is used to determine working length for the success of endodontic treatment, can be used as an alternative to the EWL method thus producing more effective results in the management of postoperative pain. However, in addition to the method used, the technology of the device developed for this method should not be ignored.Clinical relevancePrecise knowledge of the apical construction, which determines the end of the area for canal preparation and filling, is essential for the success of root canal treatment and the management of postoperative pain. For this purpose, devices based on various methods that determine the working length are used. However, it is still controversial which method provides the most accurate measurements. This study found that the simultaneous working length determination method can be used as an alternative to the electronic working length determination method and produces more effective results in the management of postoperative pain. Another important outcome of this study is that the Total Allowable Error (TEa) for the electronic apex locator method, which is accepted as the reference, has been calculated for the first time. Other methods have been evaluated according to this reference method. This is a first in literature.

New chemometrics-assisted spectrophotometric methods for simultaneous determination of co-formulated drugs montelukast, rupatadine, and desloratadine in their different dosage combinations

Two accurate, precise and robust multivariate chemometric methods were developed for the simultaneous determination of montelukast sodium (MON), rupatadine fumarate (RUP) and desloratadine (DES). These methods provide a cost-effective alternative to chromatographic techniques by utilizing spectrophotometry in pharmaceutical quality control. The proposed approaches, partial least squares-1 (PLS-1) and artificial neural network (ANN), were optimized using genetic algorithm (GA) to select the most influential wavelengths, enhancing model performance. A five-level, three-factor design was employed to construct a calibration set with 25 mixtures, utilizing concentration ranges of 3–19, 5–25, and 4–20 µg.mL−1 for MON, RUP, and DES, respectively. An independent validation set was employed to assess the performance of the models. GA significantly improved the PLS-1 and ANN models for RUP and DES, though minimal enhancement was observed for MON. These methods were successfully applied to the simultaneous quantification of the compounds in pharmaceutical formulations and proved useful as stability-indicating assays for RUP, given that DES is a known degradation product. The developed methods offer a valuable tool for impurity profiling and quality control in pharmaceutical analysis.

Development and validation of a rapid HPLC-MS/MS method for simultaneous determination of cyclosporine A and tacrolimus in whole blood for routine therapeutic drug monitoring in organ transplantation.

Therapeutic drug monitoring is an integral part of organ transplantation. A rapid, simple, economical, and robust high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for simultaneously determining the immunosuppressants cyclosporine A and tacrolimus might increase detection efficiency. In this study, we developed and validated a rapid HPLC-MS/MS method. Whole blood samples of 100 μL were prepared by protein precipitation with acetonitrile and 0.5mol. L-1 ZnSO4. Chromatography was performed on a pre-column using a gradient elution with 20mmol. L-1 ammonium formate and 0.1% (v/v) formic acid in water (mobile phase A) and 0.1% (v/v) formic acid in methanol (mobile phase B) at a flow rate of 1.5mL.min-1. The analysis time was 2.2min. Electrospray ionization and multiple reaction monitoring were performed. The lower limit of quantification was set at 1ng. L-1 for tacrolimus and 50 ng. L-1 for cyclosporine A. The method showed adequate accuracy and precision with a sufficient linear range. The calibration curve range of tacrolimus and cyclosporine A was 1-30 and 50-1500 ng·mL-1, respectively. All correlation coefficients were >0.99. The developed HPLC-MS/MS is rapid and can be used for simultaneous monitoring of tacrolimus and cyclosporine A.

Chemometric-assisted spectrophotometric methods for simultaneous drug determination in new Helicobacter pylori treatment regimens - Environmental sustainability assessment

The recent FDA approval of VOQUEZNA™ TRIPLE PAK™ 7-day therapy, which includes vonoprazan (VON), amoxicillin (AMO), and clarithromycin (CLA), marks a significant advancement in the treatment of Helicobacter pylori (H. pylori) infections. Accurate quantification of these active pharmaceutical ingredients (APIs) is critical for ensuring therapeutic efficacy and safety. However, conventional analytical methods often require extensive sample pretreatment and separation, which can be time-consuming and environmentally burdensome. This study presents the first simultaneous quantification of VON, AMO, and CLA using innovative chemometric-assisted spectrophotometric methods aligned with Green Analytical Chemistry (GAC) principles. Our methods eliminate the need for pretreatment or separation, thereby enhancing both analytical efficiency and environmental sustainability. We developed orthogonal partial least squares (OPLS), principal component regression (PCR), and Artificial Neural Network (ANN) models, utilizing the Design of Experiment (DoE) approach to minimize solvent use and waste.Model validation was achieved through Orthogonal Array-based Latin Hypercube Sampling (OALHS), ensuring robust performance evaluation. The models demonstrated high precision, with recovery percentages ranging from 98.00% to 102.00%. The calibration set model fitting was assessed using the determination coefficient (R2), and the cross-validation coefficient (Q2), all model's R2 and Q2 values were close to 1.0, indicating the calibration samples' high capacity for explanation and prediction, while the root mean square error of calibration (RMSEC) values were found to be less than 0.1. The prediction of the validation set was employed by the root mean square error of prediction (RMSEP) and relative root mean square errors of prediction (RRMSEP), the values were found (0.0335–0.0613) and (0.7207–0.5287) for RMSEP and RRMSEP, respectively, while the bias-corrected mean square error of prediction (BCMSEP) was found to be between 0.0014 and 0.0001. To evaluate and enhance the sustainability of the methods, comprehensive tools were utilized: SPIDER Solvent Tool, RGB12 Algorithm, AGREE, and the Need Quality Sustainability (NQS) Index. This work supports the Sustainable Development Goals (SDGs) by demonstrating advancements in environmentally sustainable analytical methods.

Novel RP-HPLC method for simultaneous determination of dapagliflozin and teneligliptin in tablet formulation and identification of degradation products by LC-MS/MS

BackgroundDiabetes mellitus affects millions globally, necessitating effective management strategies. Glenmark Pharmaceutical Limited introduced a fixed-dose combination of teneligliptin and dapagliflozin in 2022 to address this need. However, existing methods for their simultaneous detection are limited, lacking forced degradation studies essential for assessing drug stability.ResultsA stability-indicating RP-HPLC method was developed for the simultaneous determination of dapagliflozin and teneligliptin in pharmaceutical formulations. The separation was efficiently achieved employing a Zorbax Eclipse Plus C18 column (150 mm × 4.6 mm, 5 µm). The mobile phase comprised a mixture of 10 mM ammonium acetate buffer in water, methanol, and acetonitrile in a suitable proportion and delivered at a flow rate of 0.6 mL/min. Detection of the isocratic eluents was performed at 224 nm using a photodiode array (PDA) detector. Validation against various stress conditions, as per ICH guidelines, revealed significant degradation of teneligliptin primarily under acidic, basic, and oxidative stress. Moreover, liquid chromatography tandem mass spectrometry (LC-MS/MS)-based characterization was conducted for the primary degradation products of teneligliptin generated under acidic, basic, and oxidative conditions.ConclusionsThe developed RP-HPLC method with a stability-indicating approach provides an efficient means for the simultaneous determination of dapagliflozin and teneligliptin in pharmaceutical formulations. The significant degradation was observed under various stress conditions and also successfully separated the degradation products by this method. The proposed method directly applied for the characterization of degradation products and based on LC-MS/MS data the structure of degradation products was generated and also degradation pathways under various stress conditions were predicted. The proposed method ensured accurate and precise results in quality control process in pharmaceutical industry, and adherence to ICH validation guidelines affirms its reliability in assessing the stability of these compounds.

A high-performance thin-layer chromatography densitometric method for the separation of isomeric ceftriaxone in powder for injection formulation

The aim of this study was to develop and validate a High-Performance Thin Layer Chromatographic (HPTLC) method for simultaneous determination of ceftriaxone and ceftriaxone e-isomer in powder for injection formulation. Ceftriaxone sodium injection is an antibiotic that used globally. It has Z/E geometrical conformation, in which ceftriaxone sodium and 3 ene-isomer have Z- conformation while (E)-isomer has E- conformation and the potential toxicity of ceftriaxone (E)-isomer has been reported. Thus, to safeguard the public health, a simple and easy to use, rapid and reliable method was developed for qualitative and quantitative determination of ceftriaxone sodium and its (E)–isomer. Samples were applied on HPTLC glass plates precoated with silica gel 60F254 by using Linomat semi-auto sampler. Separation was carried out using acetone, triethyl amine, water, chloroform and ethyl acetate as a mobile phase in different ratios. The Rf values of separated compounds were 0.51 ± 0.01 and 0.62 ± 0.01 for ceftriaxone sodium and ceftriaxone (E)-isomer respectively. The method was validated by studying Specificity, Linearity, Accuracy, Precision, Robustness, Limit of Detection (LOD) and Limit of Quantification (LOQ) and Solution stability. The developed method was successfully, sensitive, simple, precise, accurate, robust and applicable for the simultaneous determination of ceftriaxone sodium and ceftriaxone (E)-isomer in powder for injection formulation.

Multiparametric LC-MS/MS method for simultaneous determination of eleven antifungal drugs and metabolites in human plasma

A multiparametric liquid chromatography-tandem mass spectrometry method has been developed for the simultaneous quantification of 11 antifungal drugs and their metabolites in human plasma. This method addresses the critical need for therapeutic drug monitoring in the treatment of invasive fungal infections, which are increasingly prevalent among immunocompromised patients and those in intensive care units. The method quantifies flucytosin, fluconazole, itraconazole, hydroxy-itraconazole, posaconazole, isavuconazole, voriconazole, voriconazole-N-oxide, anidulafungin, caspofungin, and micafungin. Key challenges in method development included optimising mass spectrometer settings, chromatographic conditions, and sample preparation techniques to ensure accurate, sensitive, and specific detection. Validation of this method was conducted in accordance with the guidelines set by the USA Food and drug administration and the European Medicines Agency covering linearity, precision, accuracy, selectivity, matrix effect, and stability. The method exhibited robust performance with intra- and inter-assay precision under 10 % and average accuracy for intra- and inter-assay comparison of −2.35 % and 0.80 %, respectively. Limits of detection (0.002 to 0.110 mg/L) and a quantification range between 0.005 and 200 mg/L make this method suitable for clinical TDM applications. The ability to simultaneously analyse eleven antifungals and their metabolites within a single 5-minute run enhances its utility in clinical settings, particularly for critically ill patients who may experience significant pharmacokinetic variations. The method requires only 100 µL of plasma, demonstrating good analytical performances rendering it a valuable tool for optimising antifungal therapy and improving patient outcomes in ICU management.

A simple, robust and high-throughput LC-MS/MS method for the therapeutic drug monitoring of polymyxin B1, polymyxin B2, polymyxin B3, isoleucine-polymyxin B1, polymyxin E1 and polymyxin E2 in human plasma.

To facilitate clinical therapeutic drug monitoring (TDM) of polymyxin B (PB) and polymyxin E (PE), we developed and validated a simple LC-MS/MS method for simultaneous determination of PB (including polymyxin B1 (PB1), polymyxin B2 (PB2), polymyxin B3 (PB3) and isoleucine-polymyxin B1 (ile-PB1)) and PE (including polymyxin E1 (PE1) and polymyxin E2 (PE2)) in human plasma. PB or PE was extracted from 20.0μL plasma using a 5% (v/v) formic acid acetonitrile solution and separated on a BEH-C18 column (2.1 × 100 mm, 1.7μm) with a mobile phase consisting of 0.8% formic acid aqueous solution and 0.2% formic acid acetonitrile solution. Gradient elution was performed over 5.5min at a flow rate of 0.250 mL/min. Quantitative analysis was conducted in positive ion scanning mode by electrospray ionization and multiple reaction monitoring. The method validation was conducted based on bioanalytical method validation guidance, including specificity, calibration curve, precision, accuracy, recovery, matrix effect, stability and dilution integrity and all of the results satisfied the requirements. The method was simple, robust and high-throughput and is currently being used to provide a TDM service to enhancing therapeutic efficacy and safety use of the PB and PE.

Efficient Online TurboFlow Method for Simultaneous Determination of 60 Emerging Per- and Polyfluoroalkyl Substances in Milk.

Emerging perfluoroalkyl and polyfluoroalkyl substances (PFASs) have received much attention in recent years. Milk has usually low concentrations of PFASs, but it remains an important PFAS exposure route due to its high consumption. In this study, a method for simultaneous determination of 60 PFASs in milk was developed by online TurboFlow liquid chromatography-tandem mass spectrometry. A pH-dependent cold-induced liquid-liquid extraction was developed for precleanup and enrichment. Method quantification limits ranged from 0.003 to 0.500 ng/mL. For PFASs without corresponding isotope-labeled internal standards, Tanimoto coefficient and logP were introduced for the selection of internal standards. The matrix spiked recoveries ranged from 47 to 190%. The method was applied for PFAS analysis in 35 milk samples. PFBS, perfluorohexanesulfonic acid, perfluorooctanesulfonic acid, PFNS, PFPeA, perfluorooctanoic acid, PFNA, and 6:2 FTS were detected. The developed online TurboFlow method was simple, reliable, efficient, and applicable for trace analysis of PFASs in milk.

Development of a Simultaneous HPLC Determination Method of Cacao Polyphenols, Caffeine and Theobromine in High Cacao Chocolate by Core-Shell Type Reversed-Phase Columns

Development of a Simultaneous HPLC Determination Method of Cacao Polyphenols, Caffeine and Theobromine in High Cacao Chocolate by Core-Shell Type Reversed-Phase Columns

Novel sulphur-selective method for simultaneous determination of thiram and asomate based on carbon dots and its application in fruits

Thiram (THI) and asomate (ASO) are frequently detected agrochemicals in food samples due to widespread use as fungicides. However, their detection suffers from matrix interference, or the necessity of derivatization before measurement. Integrating HPLC with a post-column carbon dots (CDs)–enhanced chemiluminescence (CL) system makes it possible to simultaneously separate and selectively detect ASO and THI in fruit samples free of derivatization and deep purification. The studies on mechanisms demonstrated that CD intermediates of anionic radical were responsible for the remarkable CL enhancement of ASO or THI. The CL intensity is directly proportional to the fungicide concentration, with the ranges of linearity for ASO and THI being 5–250 μg·L−1 (R2 = 0.9993) and 4–200 μg·L−1 (R2 = 0.9986), respectively, and the corresponding limits of detection (S/N = 3) being 1.61 and 1.33 μg·L−1, respectively. The developed method enables the exploration of the novelly sulphur-targeted CL application based on carbon nanomaterials.

A miniaturized QuEChERS-DLLME method for simultaneous determination of acetamide, acrylamide, and glycidamide in infant formula using GC–MS

A miniaturized QuEChERS-DLLME method for simultaneous determination of acetamide, acrylamide, and glycidamide in infant formula using GC–MS

Spectrofluorimetric Method for Simultaneous Determination of Trimethoprim and Sulfamethoxazole with &lt;i&gt;O&lt;/i&gt;-phthaladehyde Reagent by H-point Standard Addition Method

Simultaneous spectrofluorometric method described for the determination of trimethoprim (TMP) and sulfamethoxazole (SMZ) in pure and pharmaceutical preparations using H-point standard addition method (HPSAM) according to the reaction of nanograms of drugs with O-phthaladehyde (OPA) reagent to forms highly fluorescence compounds. The formed fluorophore excitation and emission at 342 and 458 nm, respectively, for OPA-TMP compound, at 424 and 508 nm, respectively, for OPA-SMZ compound under basic condition (pH 9.8) in the presence of 2-mercabtoethanol. A simple and accurate HPSAM is reported to resolve the overlapping in the fluorescence spectrum of these two drugs without prior separation of samples. The linear range was 100–1200 ng/mL for TMP and 100–1100 ng/mL for SMZ. The LOD and LOQ were 16.64 and 36.80 ng/mL, as well as 15.76 and 33.88 ng/mL for TMP and SMZ, respectively. The relative standard deviations and recovery percentages were 0.641% and 101.29% for TMP as well as 0.558% and 100.96% for SMZ, respectively. The procedure has been applied successfully in various pharmaceutical preparations. It was discovered that the experimental F- and t-values at a 95% confidence level were no higher than the theoretical values, showing that the HPSAM method is accurate and valid.

Buffer-free high pH mobile phase LC-MS/MS for determination of the alcohol biomarker phosphatidylethanol 16:0/18:1 and 20 drugs and metabolites in whole blood

BackgroundAcidic mobile phases are commonly used in reversed phase liquid chromatography tandem mass spectrometry (LC-MS/MS) bioanalysis. However, increased sensitivity, improved peak symmetry, and increased retention, especially for basic hydrophilic drugs have been observed using basic mobile phases. In our previous acidic mobile phase LC-MS/MS method we needed two injections (0.4 and 2.0 μL) of each sample for this task, which is inefficient. The aim of this study was to investigate if basic mobile phase LC-MS/MS could be used to determine phosphatidylethanol 16:0/18:1 and 20 other drugs and metabolites with satisfactory sensitivity in one single run. MethodsWhole blood was prepared by 96-well supported-liquid extraction using heptane/ethyl acetate/2-propanol (16:64:20, v:v:v). Chromatographic separation was achieved on an Acquity BEH C18 column (50 × 2.1 mm I.D.), using a mobile phase with 0.025 % ammonia, pH 10.7 (Solvent A) and methanol (Solvent B). All compounds had isotope-labelled internal standards. ResultsThe method was fully validated. Recovery was between 63 and 91 % for 20 compounds and 10 % for benzoylecgonine. Matrix effects were low, except for ion enhancement of buprenorphine and ion suppression for THC. However, internal standards compensated for these effects. Inter-assay precision and accuracy were < ± 20 % for all compounds at five tested concentrations, except for methamphetamine at the highest concentration. ConclusionAn LC-MS/MS method for simultaneous determination of PEth 16:0/18:1 and 20 drugs and metabolites in whole blood were for the first time developed and validated. Retention of PEth 16:0/18:1 was, in contrast to the other 20 compounds, largely affected by mobile phase buffer concentration. The buffer free basic mobile phase ensured that phosphatidylethanol 16:0/18:1 eluted before most of the unwanted phospholipids.

Development and validation of High-Performance Thin Layer Chromatographic methods for simultaneous determination of antibacterial pharmaceutical formulations containing Clindamycin phosphate.

The main objective of this research is to establish and authenticate the High-Performance Thin-Layer Chromatographic techniques for the simultaneous assessment of Clindamycin phosphate in combination with Tretinoin (formulation-1) and Clindamycin phosphate with Adapalene (formulation-2), both of which are antimicrobial combinations. In the developed HPTLC methods, for combination-1, the optimized mobile phase was a mixture of n-Hexane: Ethyl acetate: ACN: Methanol (5:2:2:1 by volume) with observed Rf values of 0.413 and 0.787 for Clindamycin phosphate and Tretinoin, respectively. Similarly, for combination-2, the mobile phase comprised n-Hexane: Diethyl ether: Dichloromethane: Acetic acid (4:4:2:0.1 by volume) with recorded Rf values of 0.407 and 0.559 for Clindamycin phosphate and Adapalene, respectively. The developed methods are successfully validated as per the regulatory guidelines. This approach proves to be significantly time-saving and costeffective, rendering it suitable for routine analyses of the formulations containing selected antibacterial active pharmaceutical ingredients and commercial formulations.

A general and rapid LC-MS/MS method for simultaneous determination of voriconazole, posaconazole, fluconazole, itraconazole and hydroxyitraconazole in IFI patients

ObjectiveTo establish a rapid and universal quantitative liquid chromatography tandem mass spectrometry (LC-MS/MS) method for measuring the exposure levels of five triazole antifungal drugs in human plasma, including voriconazole, fluconazole, posaconazole, itraconazole, and hydroxyitraconazole. MethodsA triple quadrupole mass spectrometer operating in positive ionization mode was used to detect the analyte, and multiple reaction monitoring mode was employed to gather data. The mobile phase included 0.05 % formic acid in water (phase A) and acetonitrile (phase B). The analytes were separated on an Agilent EclipsePlusC18 RRHD column (30 × 50 mm, 1.8 μm) using gradient elution. The flow rate was 0.3 mL/min with the column temperature set at 35 °C. The acetonitrile was used to pretreat the plasma sample, and the itraconazole-D5 and hydroxyitraconazole-D5 were utilized as the internal standards. ResultsThe calibration range was from 100 to 10,000 ng/mL for posaconazole, itraconazole, and hydroxyitraconazole, from 200 to 20,000 ng/mL for fluconazole and from 50 to 5000 ng/mL for voriconazole, with linear correlation coefficients more than 0.99 for all regression curves. The intra- and inter-day accuracy and precision of the method were within ±15 %. The mean extraction recovery of all the analytes ranged from 74.32 % to 117.83 %, and the matrix effect was from 72.54 % to 111.2 %. The results of stability fell into the scope of ±15 % deviation. ConclusionThis newly developed method is sensitive, simple, and robust, and successfully applied in determining triazole antifungal drugs in plasma from 66 IFI patients to provide reference for safe and effective drug administration in clinical practice.