Mobile Phase Of Water Research Articles

Development of a green and rapid ethanol-based HPLC assay for aspirin tablets and feasibility evaluation of domestically produced bioethanol in Thailand as a sustainable mobile phase

Abstract Despite the growing trend of using ethanol as a greener alternative to hazardous solvents like methanol and acetonitrile in high-performance liquid chromatography (HPLC) analysis, no ethanol-based assay has been developed for aspirin tablets, nor has the potential of domestically produced bioethanol as a mobile phase been explored – until now. This study introduces a novel ethanol-based HPLC assay for aspirin and assesses the feasibility of using locally produced bioethanol. The optimized method, featuring a 40% (v/v) ethanol–water mobile phase adjusted to pH 3.6 with glacial acetic acid, with a 15-cm C18 column at 40°C and UV detection at 237 nm, successfully separated aspirin and its degradation product, salicylic acid, in 5 min. It demonstrated excellent linearity (0.1–0.6 mg·mL−1, r² = 0.9997), sensitivity (LOD = 0.01 mg·mL−1, LOQ = 0.03 mg·mL−1), accuracy, and precision, with no interference from excipients. The method’s performance on commercial aspirin tablets aligned with official pharmacopoeial methods. In a case study using fuel-grade bioethanol (>99.5% purity) derived from sugarcane molasses or cassava from local manufacturers in Thailand, chromatographic and analytical results matched those obtained with imported ethanol, validating its effectiveness. This innovative approach not only reduces costs and dependence on imported solvents but also supports local bio-circular-green economies and promotes greener, more sustainable analytical practices.

A Validated Method for Identification and Quantification of Anthocyanins in Different Black Rice (Oryza sativa L.) Varieties Using High-Performance Thin-Layer Chromatography (HPTLC).

Black rice (Oryza sativa L.) has gained prominence as a functional food because of its rich content of anthocyanins and polyphenols, offering potential health benefits. However, comprehensive research addressing the diverse anthocyanin compositions in black rice cultivars remains limited. This study aimed to quantify anthocyanin contents, specifically kuromanin, cyanidin-3-glucoside, peonidin-3-O-glucoside, peonidin-3-glucoside chloride, and cyanidin-3-rutinoside chloride, in 150 rice varieties sourced from the North Eastern Region of India using a robust high-performance thin-layer chromatography (HPTLC) method. Rice grains of varying colors-black, orange-reddish, and white-were subjected to methanol extraction under dark conditions through cold maceration for 72 h. The resulting extracts underwent separation on HPTLC silica gel 60 F254 plates utilizing an optimized mobile phase of ethyl acetate, 2-butanol, formic acid, and water (9:6:3:3::v/v/v/v). Anthocyanins were found to be present, and they were most visible in white light compared with UV light at 254 and 366 nm. They were analyzed via densitometry under white light illumination in transmission mode following development. Notably, anthocyanins were absent in grains of white and orange-reddish rice varieties, except for specific lines of Joha (JN 71, JN 83, JN 77, and JN 78) and all black rice variants. Among these, BR 15 exhibited the highest kuromanin content (74.14 ± 0.82 μg/mg), while BR8 showcased the highest peonidin-3-glucoside chloride concentration (27.59 ± 0.83 μg/mg). This comprehensive analysis provides detailed insights into the anthocyanin compositions of 15 significant black rice cultivars, offering crucial data for breeding programs targeting enhanced anthocyanin-rich cultivars and the development of functional foods.

Polyoxometalates ionic liquids based magnetic nanocomposites as an efficient heterogeneous catalysts for oxidation of thiobenzoic acid and dibenzothiophene by employing RP-HPLC-UV

Sulfur compounds need to be effectively rejected from fuel to maintain a clean environment. The removal of sulfur compounds from thiocompounds has received increased attention due to the negative environmental and industrial consequences of sulfur emissions. We examine the effectiveness of polyoxometalate (POM) ionic liquid-based nanocomposites as catalysts for the oxidative desulfurization of thiobenzoic acid and other sulfur-containing chemicals. Na-POMIL@NCP and Cr-POMIL@NCP were synthesized and thoroughly characterized using a variety of analytical techniques, including Fourier-transform infrared spectroscopy (FT-IR), UV–visible spectroscopy, powder X-ray diffraction (P-XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), fluorescence spectroscopy, and vibrating sample magnetometer (VSM). POMIL-based nanocomposites with Fe3O4@SiO2 exhibit both catalytic activity and adsorption capability. To evaluate sulfur removal efficiency and investigate the transformation paths of the thio compounds, high-performance liquid chromatography (HPLC) was performed at 33 °C using a C18 column with an acetonitrile–water mobile phase (1:1 ratio). The catalytic conversion of thiobenzoic acid and dibenzothiophene occurs at temperature, oxidant O/S ratio and catalyst concentration were investigated to determine the best catalyst for a given process. Under moderate conditions, this work proposes a cost-effective and ecologically acceptable approach for thiobenzoic acid (TB) and dibenzothiophene (DBT) production employing H2O2 as an oxidant and Na-POMIL@NCP and Cr-POMIL@NCP as heterogeneous catalysts. They are highly effective for oxidizing sulfur compounds included in diesel to lower the sulfur levels of fuel. This study provides to the development of innovative materials for ecologically friendly sulfur removal applications.

Serum pharmacochemistry of Panacis Japonici Rhizoma extract based on UPLC-Q-Exactive Orbitrap-MS

In this study, the chemical components of Panacis Japonici Rhizoma extract and absorbed components in rats were identified by ultra-high performance liquid chromatography-quadrupole exactive orbitrap mass spectrometry(UPLC-Q-Exactive Orbitrap-MS). The separation was performed by gradient elution on Waters UPLC BEH C_(18) column(2.1 mm×100 mm, 1.7 μm) with the mobile phase of water and acetonitrile containing 0.1% formic acid. High resolution multistage mass spectrometry data were collected by electrospray ionization in positive and negative ion modes. The chemical components of Panacis Japonici Rhizoma extract were identified by comparing with the retention time, high resolution precise molecular weight, and secondary fragment ions of reference substances and related literature. After intragastric administration of Panacis Japonici Rhizoma extract, blood was collected from the abdominal aorta of rats for separation of the serum, and the absorbed components were scanned and identified. The results showed that 43 chemical components were detected in the Panacis Japonici Rhizoma extract, including 22 saponins, 9 amino acids, 5 polysaccharides, 2 volatile oils, and 5 nucleosides. In the serum, 18 components were detected, including 10 prototype components, 6 metabolites, and 2 unknown components. This study analyzed the chemical components and absorbed components of Panacis Japonici Rhizoma extract, providing clues for clarifying the pharmacological basis of Panacis Japonici Rhizoma.

Identification of Degradation Pathway of Bilastine and Montelukast by LC/MS

It is necessary for a dosage form to maintain their chemical, physical, microbiological and toxicological stability during their entire shelf life. Knowing the intrinsic stability of the chemical and the breakdown pathway of the dosage form is crucial for this reason. We have developed a straightforward analytical approach using HPLC-UV/MS for the simultaneous measurement of Bilastine and Montelukast, as well as the identification of their degradants in tablet formulation. This method is specific, linear, accurate, and robust. The narcotic compounds were broken down one by one. The Zorbax XDB C-18 column (150*4.6) mm, 5µ, with a mobile phase of Water:Acetonitrile:Formic acid (50:50:1), was used to achieve the separation. A flow rate of 1 ml/min was used with an injection volume of 20 µl. A UV-Vis Spectrophotometer was used for peak detection, while a mass spectrophotometer was employed for identification. Bilastine had a retention time of 3.22 minutes and Montelukast of 4.80 minutes. Proposed method was stability indicating, specific, linear, accurate and robust. The degradation pathway was established for Bilastine and Montelukast by studying their degradation in various stress conditions. The Bilastine was found stable in Photolytic and thermal degradation while there was degradation observed in Montelukast in all stress conditions.

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.

Identification and quantification of potential genotoxic impurity N-nitroso isoproterenol in bradycardia drug isoproterenol hydrochloride by LC-MS/MS technique

A highly sensitive and robust LC-MS/MS method was developed and validated for the quantification of N-Nitroso Isoproterenol (NNIP) impurity in Isoproterenol Hydrochloride. The method employed a Heated Electrospray Ionization (HESI) source, with selective reaction monitoring (SRM) mode and with 3600 Voltage negative ion, to detect NNIP with a precursor ion of 238.967 m/z and product ions of 136.883 m/z and 190.967 m/z. Chromatographic separation was achieved using a Kinetex-Biphenyl 100Å (250 mm x 4.6 mm, 5 µm) column with a gradient program consisting of 0.1% Formic acid in Water (Mobile Phase A) and 0.1% Formic acid in Methanol (Mobile Phase B). The method demonstrated excellent linearity (R2 = 0.9982) across concentrations from LOQ to 150% of the target level, with a limit of detection (LOD) of 1.14 ppm and a limit of quantification (LOQ) of 3.46 ppm. Precision, indicated by a %RSD of 3.1%, and accuracy, with recoveries ranging from 91.3% to 103.6%, confirmed the method’s reliability. The NNIP peak was consistently observed at 8.56 minutes, supporting the method’s applicability for routine analysis of NNIP impurity in Isoproterenol Hydrochloride formulations.

RGB Trichromatic Whiteness Assessment of Bio Analytical Chromatographic Tool Using Fluorescence for Quantitation of Semaglutide: Application to Pharmaceutical Preparations and Spiked Plasma.

Semaglutide (SEMG) is one of the most widely used and trending medications to treat type II diabetes and obesity.This work aimed to develop a liquid chromatography with spectroflourimetric detection (HPLC-flourimetry) analysis of SEMG in both its tablet dosage form and plasma. The power of fluorescence detection coupled with HPLC proved its capability as a bioanalytical tool to assay SEMG in plasma samples owing to its simplicity and sensitivity which reached below the Cmax of SEMG. Separation was done using a C18 column with mobile phase of acetonitrile and water acidified with orthophosphoric acid (pH 3.5) (1.41 × 10-5M) in isocratic mode in ratio 57:43 and 1mL/min flow rate after extraction using protein precipitation. Detection was carried out at λ excitation of 238nm and λ emission of 416 and 307nm for SEMG and the internal standard, respectively. Evaluation of greenness of the proposed method was done using AGREE (Analytical GREEnness Metric Approach), ComplexGAPI (Complementary Green Analytical Procedure Index) & the new algorithm RGB 12 model (Red-Green-Blue). They showed that these methods can be a greener alternative with acceptable sensitivity for analysis of SEMG. The developed seven min-assay was validated per ICH as well as FDA bio analytical methods' guidelines to prove its applicability for routine sample analysis and future pharmacokinetic studies.

Development of a QAMS Analysis Method for Industrial Lanolin Alcohol Based on the Concept of Analytical Quality by Design

The Analytical Quality by Design (AQbD) concept was adopted to establish a quantitative analysis of multi-components with a single marker (QAMS) method for industrial lanolin alcohol, targeting cholesterol, lanosterol, and 24,25-dihydrolanosterol. The potential critical method parameters (CMPs) were identified as column temperature, flow rate, and gradient. Definitive screening design and statistical modeling were employed to optimize the gradient conditions of the mobile phase, column temperature, and flow rate. The Method Operable Design Region (MODR) was determined using a risk-based quantification approach. The robustness was assessed using a Plackett–Burman experimental design, followed by methodological validation. Optimal analytical conditions were as follows: acetonitrile (B)—water (A) mobile phase system; flow rate of 1.58 mL/min; detection wavelength of 205 nm; injection volume of 10 µL; and column temperature of 37 °C. A gradient elution program was implemented as follows: 0–19.0 min, 90.5% B; 19.0–25.0 min, 90.5–100% B; and 25.0–55.0 min, 100% B. Cholesterol served as an internal standard for quantifying lanosterol and 24,25-dihydrolanosterol, with relative correction factors of 0.4227 and 0.8228, respectively. This analytical method utilized only the cholesterol reference substance as an internal standard to quantify the content of cholesterol, lanosterol, and 24,25-dihydrolanosterol in industrial lanolin alcohol. It reduced the testing costs and enhanced efficiency, making it potentially suitable for widespread adoption in lanolin alcohol processing industries.

Development and Validation of an LC-MS/MS Assay for the Quantitation of MO-OH-Nap Tropolone in Mouse Plasma: Application to In Vitro and In Vivo Pharmacokinetic Studies.

A rapid, selective, and sensitive liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantitation of MO-OH-Nap tropolone (MO-OH-Nap) in mouse plasma. MO-OH-Nap is an α-substituted tropolone with anti-proliferative properties in various cancer cell lines. Detection and separation of analytes was achieved on an ACE Excel C18 (1.7 µm, 100 × 2.1 mm, MAC-MOD Analytical, Chadds Ford, PA, USA) column with mobile phase consisting of 0.05% trifluoroacetic acid in water (mobile phase A) and 0.05% trifluoroacetic acid in acetonitrile (mobile phase B), with an isocratic elution of 15:85% (A:B) at a total flow rate of 0.25 mL/min. The LC-MS/MS system was operated at unit resolution in multiple reaction monitoring (MRM) mode, using precursor ion > product ion combination of 249.10 > 202.15 m/z for MO-OH-Nap and 305.10 > 215.05 m/z for the internal standard (IS), BA-SM-OM. The MS/MS response was linear over a concentration range of 1 to 500 ng/mL with a correlation coefficient (r2) of ≥0.987. The within- and between-batch precision (%RSD) and accuracy (%Bias) were within acceptable limits. The validated method was successfully applied to determine MO-OH-Nap metabolic stability, plasma protein binding, and bio-distribution studies of MO-OH-Nap in CD-1 mice.

Retention factor variation on wide range of mobile phase compositions in reversed-phase high-performance liquid chromatography; a short tutorial

Mobile phase composition remains the major experimental parameter influencing the separation process in reversed-phase high-performance liquid chromatography (RP-HPLC). Its influence on the retention of solutes is explained by the Hildebrand solubility parameter and solvophobic theory, which also considers molecular characteristics of the participants in a separation process. The main empirical dependences (linear and polynomial) between the retention factor and the composition of mobile phase (retention function) are discussed taking into consideration a wide range of mobile phase compositions. Two direct chromatographic indices are resulting from these equations: the extrapolated value of retention factor for zero organic content in mobile phase composition (log kw) and the solvent strength parameter (S), which for a linear retention function is its slope being constant over the entire mobile phase compositions. Another chromatographic index could result from the retention function for zero content of water in mobile phase, but this situation can be applied only for very hydrophobic solutes. For large domains of mobile phase composition, the retention function cannot be described by a single type of dependence. This explains the paradox of generating by extrapolation different logkwvalues for different organic components. For the mobile phase close to pure water the retention function is different from that at average water concentration.

Per aqueous liquid chromatography of Radix hedysari polysaccharides and Au nanoparticles co-functionalized stationary phase and its application in the determination of iridoids and phenylethanols

BackgroundHydrophilic Interaction Liquid Chromatography (HILIC) is an outstanding strategy for the challenging analysis of hydrophilic and polar components. Nevertheless, analysis under HILIC mode typically consumes 70%–95 % acetonitrile with the disadvantage of high analytical costs, being environmentally unfriendly and causing biohazards, which is not in line with the concept of green chromatography. Research has shown that Per Aqueous Liquid Chromatography (PALC) simultaneously emphasizes efficient analytical performance for hydrophilic analytes and green analytical concepts. The development of new PALC stationary phases with superior performance is necessary. ResultsIn this paper, silanized silica was sequentially subjected to esterification reaction, polymerization reaction and covalent bonding through five steps to obtain SiO2-RHP-AuNPs material, which was prepared as a novel stationary phase for PALC. Comprehensive characterization of the materials by means of Fourier transform infrared spectroscopy, Transmission scanning electron microscope, Elemental analysis and Thermogravimetric analysis showed the successful bonding of the functionalized groups on the original silica. The polymeric stationary phase based on Radix hedysari polysaccharide and Au nanoparticles had higher density of hydroxyl and ester functionalized groups. The Au nanoparticles upgraded their mesoporous structure and thermal stability, providing exceptional chromatographic performance and selectivity for chromatographic analysis. The influence of mobile phase water content, salt concentration, pH and column temperature on the retention behavior was evaluated. The novel Column was found to exhibit a dual mechanism of hydrophobic interactions/ion exchange interactions in a mobile phase with high water content. Significance and noveltyThe separation efficiency and selectivity of SiO2-RHP-AuNPs columns for synthetic pigments and organic acids in PALC mode were superior to those of commercial HILIC and C18 columns. In addition, a method for the determination of seven active ingredients in Fructus Ligustri Lucidi by SiO2-RHP-AuNPs column in PALC mode was developed. The method had good stability, reproducibility and accuracy, which was capable of realizing the quality evaluation of Chinese Materia Medicas.

Quantifying Phospholipids in Organic Samples Using a Hydrophilic Interaction Liquid Chromatography-Inductively Coupled Plasma High-Resolution Mass Spectrometry (HILIC-ICP-HRMS) Method.

In this study, a novel method using hydrophilic interaction liquid chromatography (HILIC) coupled with inductively coupled plasma high-resolution mass spectrometry (ICP-HRMS) was introduced for the quantification of phospholipids in oil samples. The method employed a bridged ethyl hybrid (BEH) stationary phase HILIC column with a tetrahydrofuran (THF)/water mobile phase, enhancing the solubility and detection of phospholipids. During the study, a gradient/matrix effect on ICP-HRMS sensitivity was observed and successfully compensated for experimentally, ensuring reliable quantification results. This approach has proven effective for a wide range of different oil samples including vegetable oils, animal fats, and phospholipid supplements. Notably, this method allowed the direct quantification of phospholipids in oil samples, bypassing the need for prior sample preparation methods, such as solid phase extraction (SPE), thereby streamlining the analytical process. The precision, accuracy, and reduced need for extensive sample preparation offered by this method mark a significant advancement in lipids analysis. Its robustness and broad applicability have substantial implications for industries such as food and renewable energy production, where both efficient and accurate lipid identification and quantification are crucial.

Development of Quality Standard and a Comprehensive Quality Control Study of Bharngyadi Kvatha Churna: An Ayurvedic Formulation

Background: Bharngyadi Kvatha Churna (BKC) is an important polyherbal formulation mentioned in the Ayurvedic Formulary of India (AFI) for the treatment of intermittent fever and chronic fever but lacks the presence of standardised quality control parameters. Aims: The aim of the present study was to develop a quality standard of BKC and to carry out a comprehensive quality control study, including the evaluation of physicochemical parameters, safety parameters, elemental content, secondary metabolites, and selected phytochemical analysis. Methods: In HPTLC analysis, piperlongumine was quantified in BKC using a silica gel-coated aluminium plate and developing solvent of toluene: acetone (6:4 v/v). In HPLC analysis, piperine was quantified using acetonitrile: water (80: 20 v/v) mobile phase, and ellagic acid was quantified using water (0.05% KH2PO4): acetonitrile (70: 30 v/v) mobile phase. ICP-OES was used to determine elemental content. The estimation of secondary metabolites like total sugars, tannins, flavonoids, alkaloids, and saponins was also carried out using a UV-Vis spectrophotometer. The volatiles present in the volatile oil of BKC were analysed using the gas chromatography-mass spectrometry technique. Results: The physicochemical parameters namely, loss on drying, total ash, acid-insoluble ash, alcohol- soluble extractive, water-soluble extractive, pH (10% aq. susp.), and volatile oil ranged from 10.56% to 11.06%, 4.67% to 5.76%, 0.73% to 1.78%, 7.56% to 8.2%, 12.04% to 13.06%, 5.87% to 5.96%, and 0.091% to 0.097%, respectively. The amount of piperlongumine in BKC ranged from 0.7688 mg/g to 0.9902 mg/g. The amount of piperine and ellagic acid ranged from 0.1180% to 0.1362% and 0.0016% to 0.0034%, respectively. Oleyl alcohol is the major volatile phytochemical present in BKC. Conclusions: The developed standardised quality control parameters of BKC would aid the herbal industry in developing BKC with requisite quality.

Anticandidal effect of cinnamic acid characterized from Cinnamomum cassia bark against the fluconazole resistant strains of Candida.

Candida spp., causes invasive fungal infections, especially in immune-compromised patients and the propensity of antifungal resistance against azole-based drugs need to be addressed. This study is thus aimed to characterize the anticandidal effect of the cinnamic acid extracted from the barks of Cinnamomum cassia. Five species of Fluconazole-resistant Candida sp. were retrieved from the department repertoire. The extraction of CA was performed by three different methods followed by silica gel column chromatography. Eluant was subjected to FTIR and XRD analysis for confirmation. The anticandidal activity of the CA was checked by the agar disc diffusion method and the MIC and MFC were determined. The anti-biofilm effect of CA was assessed using the CLSM technique followed by the biocompatibility check using MTT assay in normal HGF cell lines. CA was best extracted with the hot maceration method using ethanol with a maximum yield of 6.73mg. Purification by column chromatography was achieved using benzene, acetic acid, and water (6:7:3) mobile phase. CA was confirmed by FTIR with absorption peaks and by XDR based on strong intensity. CA was found to possess promising anticandidal activity at 8µg/mL with MIC and MFC values determined as 0.8µg/mL and 0.08µg/mL respectively. Antibiofilm activity by CLSM analysis revealed biofilm inhibition and was biocompatible at 8.5µg/ml concentrations in HGF cell lines until 24h. The study findings conclude that CA is the best alternative to treat candidal infection warranting further experimental preclinical studies.

A multianalyte LC-MS/MS method for accurate quantification of Nitrosamines in Olmesartan tablets

This research summaries the development, optimization and validation of liquid chromatography tandem mass spectrometric (LC-MS/MS) method for concurrent measurement of seven nitrosamines viz; NDMA, NDEA, NDIPA, NDPA, NEIPA, NMPA & NMBA in Olmesartan tablet. Controlling these nitrosamines at trace levels is imperative for ensuring the safety of drug substances and products for consumption. Various regulatory authorities stress the significance of utilizing highly sensitive analytical methods to precisely measure nitrosamines at trace levels. The method applied effective chromatographic separation and optimized parameters for mass spectrometric detection. Detection was carried out using APCI positive ion mode. Chromatographic separation was achieved using a Thermo Accucore PFP column (150 mm x 4.6 mm, 2.6 µ), with a simple gradient elution of mobile phase consisting of 0.1 % formic acid in water (mobile phase A) and methanol (mobile phase B). The total run time was 20 min, with a flow rate of 0.800 mL/min.The method was validated according to the International Council on Harmonisation (ICH Q2 (R2)) guidelines. The established method demonstrated excellent linearity (R2> 0.99) and sensitivity for all the nitrosamines. Detection and quantification limits were sufficiently low for trace nitrosamine levels having good S/N ratio. The method showed good accuracy in Olmesartan tablet samples, with recoveries ranges between 80 % to 120 %. The new analytical approach has exceptional repeatability and reliability, making it possible to precisely quantify the levels of seven nitrosamines in Olmesartan medoxomil tablets in a single analytical run.

Modification of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method targeting lysergic acid diethylamide (LSD) and its primary metabolite (OH-LSD) to include nine LSD analogs.

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

Simultaneous Quantification of Dutasteride and Silodosin Using a Stability-Indicating RP-HPLC Approach

An alternative stability-indicating reverse-phase high-performance liquid chromatography (RP-HPLC) approach remained established to quantify silodosin (SLD) and dutasteride (DTS) in the mixture, validated per International Council of Harmonization (ICH) recommendations. A Shimadzu Model LC-2030 PLUS (IND) HPLC system, 231 nm detection wavelength, and 10 minutes run duration were used to create the method. A 75:25 mobile phase of methanol and water with 0.05% OPA was used at 1-mL/min. The concentrations of SLD (8–40 μg/mL) and DTS (0.5–2.5 μg/mL) were shown to be linearly related, with R2 values of 0.9998 for SLD and 0.9993 for DTS. Both of the drugs had accuracy and precision within 2% RSD. SLD and DTS mean recoveries were 97.5 to 102%. According to ICH criteria, degradation trials with acid, alkali, oxidizing agent, and heat assessed the approach’s stability. The established approach is fast, accurate, sensitive, and precise for routine SLD and DTS analysis from bulk as well as pharmaceutical dosage forms.

A simple method for the determination of acyclovir concentrations in human plasma using high-performance liquid chromatography

BackgroundAcyclovir is an anti-viral medication given to treat herpes simplex and herpes zoster infection. In some severe conditions such as herpes encephalitis, acyclovir is administered intravenously. However, high acyclovir doses may cause acute kidney injury and low acyclovir dose may predispose the patient to inadequate exposure to acyclovir which could be fatal in some conditions. In such cases, the acyclovir plasma concentrations will potentially guide the diagnosis and management of the kidney injury. In this study, we provide a simple and time-efficient method for analyzing acyclovir in human plasma using high-performance liquid chromatography (HPLC).ResultsThe process starts with a single protein precipitation step by adding acetonitrile to deproteinize 300 µL of plasma. The chromatographic separation conditions consist of a mobile phase of water: methanol (97:3, v/v), a flow rate of 1 mL/min, a run time of 17 min, and a detection wavelength of 254 nm. The calibration curve was linear over the range of (0.70–60 mg/L) (r2 ˃ 0.99). The retention times of acyclovir and the internal standard were around 15 and 12 min, respectively. The intra-day and inter-day analysis of acyclovir in plasma using this method exhibited accuracy and precision of less than 7%, which lies within the acceptable range. Different greenness assessment tools confirmed that the proposed method is eco-friendly.ConclusionThe proposed method of analysis of acyclovir in the plasma using HPLC is simple, green and accurate method. This method could be applied in clinical settings where monitoring acyclovir concentrations is essential as it has wide range of the concentrations that could be detected.

Simultaneous determination of maltol and seventeen saponins in red and black ginseng by UPLC-PDA wavelength switching method

This study developed a UPLC-PDA wavelength switching method to simultaneously determine the content of maltol and seventeen saponins in red and black ginseng and compared the quality differences of two different processed products of red and black ginseng. A Waters HSS T3 column(2. 1 mm×100 mm, 1. 8 μm) at 30 ℃ was adopted, with the mobile phase of acetonitrile(A) and water containing 0. 1% phosphoric acid(B) under gradient elution, the flow rate of 0. 3 m L·min~(-1), and the injection volume of 2 μL.The wavelength switching was set at 273 nm within 0-11 min and 203 nm within 11-60 min. The content results of multiple batches of red and black ginseng samples were analyzed by the hierarchical cluster analysis(HCA) and principal component analysis(PCA) to evaluate the quality difference. The results showed that the 18 constituents exhibited good linear relationships within certain concentration ranges, with the correlation coefficients(r) greater than 0. 999 1. The relative standard deviations(RSDs) of precision,repeatability, and stability were all less than 5. 0%. The average recoveries ranged from 95. 93% to 104. 2%, with an RSD of 1. 8%-4. 2%. The content determination results showed that the quality of red and black ginseng samples was different, and the two types of processed products were intuitively distinguished by HCA and PCA. The method is accurate, reliable, and reproducible. It can be used to determine the content of maltol and seventeen saponins in red and black ginseng and provide basic information for the quality evaluation and comprehensive utilization of red and black ginseng.