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Ginsenoside Re was the major bioactive component found rich in Panax ginseng C. A. Meyer, which exerted excellent cardiovascular protection, anti-inflammatory, and anti-oxidation effects. The generation of unexpected degradation products (DPs) may influence the therapeutic effect of Re, or even bring toxic effects to patients. However, to date, only a few reports were available about the stability of Re. The present study aims to systematically investigate the degradation behaviors of Re under different stress conditions, including hydrolysis (acidic, basic, and neutral), oxidation, humidity, thermal, and photolytic (ultraviolet and visible light) conditions. A total of thirteen DPs were putatively identified, and among them, nine were discovered for the first time in our study. The results showed that Re was sensitive to exposure to acidic, basic, and oxidation conditions. It underwent a series of chemical degradation reactions, including deglycosylation, dehydration, addition, oxidation at the double bond, and isomerization under various stress conditions. Structural characterization of these DPs was carried out by UHPLC-DAD-CAD and LC-LTQ/Orbitrap. A plausible mechanism of their formation was proposed to support the structures of all DPs of Re. In silico toxicity prediction and metabolism behavior assessment were done by Derek Nexus and Meteor Nexus software. Re and DP-1 to DP-6 were predicted to possess potential skin irritation/corrosion toxicity. DP-11 and DP-12 bear the potential for carcinogenicity, mutagenicity, irritation, hepatotoxicity, and skin sensitization. The observation of these DPs updates our knowledge regarding the stability of Re, which provides valuable information for quality control and to choose suitable storage conditions. [ABSTRACT FROM AUTHOR]

Dissolved organic matter (DOM) is a complex mixture of thousands of molecular formulas comprised of an unknown number of chemical compounds, the concentration and composition of which are critical to ecosystem function and biogeochemical cycling. Despite its importance, our understanding of the DOM composition is lacking. This is principally due to its molecular complexity, which means that no single method is capable of describing DOM in its entirety. Quantification is typically done by proxy (e.g., relative to carbon content) and does not necessarily match well to compositional data, due to incomplete analytical windows and selectivity of different analytical methods. We present an integrated liquid chromatography (LC)–diode array detector (DAD)–charged aerosol detector (CAD)–mass spectrometry (MS) pipeline designed to both characterize and quantify solid-phase extractable DOM (SPE-DOM) in a single analysis. We applied this method to a set of eight Swedish water bodies sampled in the summer and winter. Chromophoric SPE-DOM was proportionally higher in samples with higher SPE-DOM concentrations but remained relatively consistent between sampling occasions. Ionizable SPE-DOM was relatively consistent across sites but was proportionally higher in summer. Overall, the carbon content of DOM was very consistently ∼40% across sites in both summer and winter. These findings suggest that SPE-DOM concentration at these sites is driven by (presumably allochthonous) chromophoric inputs, with an increased relative contribution in summer of material that is more ionizable and less chromophoric and may be either autochthonous or selectively enriched from allochthonous sources. Thus, with minimal additional effort, this method provided further compositional insights not attained by any single analysis in isolation. [ABSTRACT FROM AUTHOR]

The charged aerosol detector (CAD) measures the overall charge deposited on aerosolized particles to produce a signal proportional to the mass of analyte present, which applies to compounds with or without a chromophore. A significant benefit of CAD is the ability to quantitate a wide range of non-volatile compounds in absence of their authentic standards due to uniform response factor for such analytes. CAD is also a valuable tool to help detect and/or quantitate compounds with poor or no UV absorption. These can include salts, impurities, and a variety of other types of analytes.In this tutorial, fundamental principles of CAD and its utilization, troubleshooting, and maintenance will be demonstrated to ensure proper CAD usage. Successful operation of CAD includes optimizing power function value (PFV) to allow for a broader dynamic range and improve uniformity of response. The use of an inverse gradient (admixed post-column) enables more accurate quantitation, when employing a gradient analysis method. Several troubleshooting strategies, including diagnosing inverse gradient pump organic solvent delivery and determining volume match/mismatch between the inverse gradient and system pumps, will be presented along with important aspects of operating a CAD. Lastly, ensuring reliable results involves monitoring the performance of CAD over time to understand whether it is working sufficiently or if maintenance is required.

Natural polysaccharides are important active biomolecules. However, the analysis and structural characterization of polysaccharides are challenging tasks that often require multiple techniques and maps to reflect their structural features. This study aimed to propose a new heart-cutting two-dimensional liquid chromatography (2D–LC) method for separating and analyzing polysaccharides to explore the multidimensional information of polysaccharide structure in a single map. That is, the first-dimension liquid chromatography (1D–LC) presents molecular-weight information, and the second-dimension liquid chromatography (2D–LC) shows the fingerprints of polysaccharides. In this 2D–LC system, the size-exclusion chromatography–hydrophilic interaction chromatography (SEC–HILIC) model was established. Coupling with a charged aerosol detector (CAD) eliminated the need for the derivatization of the polysaccharide sample, allowing the whole process to be completed within 80 min. The methods were all validated in terms of precision, linearity, stability, and repeatability. The capability of the new 2D-LC method was demonstrated in determining various species of natural polysaccharides. Our experimental data demonstrated the feasibility of the whole systematic approach, opening the door for further applications in the field of natural polysaccharide analysis. [ABSTRACT FROM AUTHOR]

The authenticity of coffee beans was addressed in this study using an analytical method with minimal sample preparation to achieve simple oil extraction and through the implementation of cost-effective equipment. For this purpose, methods using UHPLC with CAD and FLD detectors were applied to detect triglycerides and tocopherols in coffee, respectively. The coffee samples included two main varieties: Arabica from Brazil, Colombia, Ethiopia, and Uganda, as well as the Robusta variety from Cambodia, Guatemala, India, and Vietnam. The samples were either in their green state or subjected to different roasting levels. The used methods successfully distinguished the Arabica and Robusta variants targeted in this study based on their tocopherols and TAG profiles, with the latter being particularly effective for discriminating the origins of the Arabica coffee, while tocopherols excelled at differentiating the origin of the Robusta coffee. TAGs and tocopherols were not affected by the type of roasting, from medium to very dark, suggesting it is possible to distinguish between coffee varieties independently from their degree of roasting. The obtained results hold valuable implications for future research regarding coffee fraud and authenticity. [ABSTRACT FROM AUTHOR]

In organic purity assessment, chromatography separation with a suitable detector is required. Diode array detection (DAD) has been a widely used technique for high-performance liquid chromatography (HPLC) analyses, but its application is limited to compounds with sufficient UV chromophores. Charged aerosol detector (CAD), as a mass-dependent detector, is advantageous for providing a nearly uniform response for analytes, regardless of their structures. In this study, 11 non-volatile compounds with/without UV chromophores were analyzed by CAD using continuous direct injection mode. The RSDs of CAD responses were within 17%. For saccharides and bisphenols, especially, the RSDs were lower (2.12% and 8.14%, respectively). Since bisphenols exist in UV chromophores, their HPLC–DAD responses were studied and compared with CAD responses, with CAD showing a more uniform response. Besides, the key parameters of HPLC-CAD were optimized and the developed method was verified using a Certified Reference Material (CRM, dulcitol, GBW06144). The area normalization result of dulcitol measured by HPLC-CAD was 99.89% ± 0.02% (n = 6), consistent with the certified value of 99.8% ± 0.2% (k = 2). The result of this work indicated that the HPLC-CAD method could be a good complementary tool to traditional techniques for the purity assessment of organic compounds, especially for compounds lacking UV chromophores. [ABSTRACT FROM AUTHOR]

Natural polysaccharides are important active biomolecules. However, the analysis and structural characterization of polysaccharides are challenging tasks that often require multiple techniques and maps to reflect their structural features. This study aimed to propose a new heart-cutting two-dimensional liquid chromatography (2D–LC) method for separating and analyzing polysaccharides to explore the multidimensional information of polysaccharide structure in a single map. That is, the first-dimension liquid chromatography (1D–LC) presents molecular-weight information, and the second-dimension liquid chromatography (2D–LC) shows the fingerprints of polysaccharides. In this 2D–LC system, the size-exclusion chromatography–hydrophilic interaction chromatography (SEC–HILIC) model was established. Coupling with a charged aerosol detector (CAD) eliminated the need for the derivatization of the polysaccharide sample, allowing the whole process to be completed within 80 min. The methods were all validated in terms of precision, linearity, stability, and repeatability. The capability of the new 2D-LC method was demonstrated in determining various species of natural polysaccharides. Our experimental data demonstrated the feasibility of the whole systematic approach, opening the door for further applications in the field of natural polysaccharide analysis.

Hongbao Liang,1– 3,&ast; Chenghong Sun,2,3,&ast; Zhong Feng,2– 4 Xianzhen Wang,2 Lingpeng Kong,2,3 Feng Zhu,2,3 Jingchun Yao,2,3 Xiaomei Yuan,3 Zhong Liu,2,3 Guimin Zhang,2,3 Feng Li1 1School of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, People’s Republic of China; 2Center for Drug Safety Evaluation, Shandong New Time Pharmaceutical Co., Ltd., Linyi, People’s Republic of China; 3State Key Laboratory of Generic Manufacture Technology of Chinese Traditional Medicine, Lunan Pharmaceutical Group Co., Ltd., Linyi, People’s Republic of China; 4School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Feng Li, Shandong University of Traditional Chinese Medicine, No. 4655 Daxue Road, Jinan, 250355, People’s Republic of China, Tel +86 139 6914 1796, Email 13969141796@163.com Guimin Zhang, Lunan Pharmaceutical Group Co., Ltd., State Key Laboratory of Generic Manufacture Technology of Chinese Traditional Medicine, No. 209 Hongqi Road, Linyi, 276006, People’s Republic of China, Tel +86 539-5019206, Email lunanzhangguimin@yeah.netBackground: To improve the dissolution and bioavailability of the component-based Chinese medicine of Ginkgo biloba leaves (GBCCM), a novel nanocrystalline solid dispersion of GBCCM (GBCCM NC-SD) was first prepared.Methods: GBCCM mainly containing high pure flavonoid aglycones (FAs) and terpenoid lactones (TLs) was used as the model drug. PVP K30 and SDS were used as solubilizers, combined stabilizers and carriers, and GBCCM NC-SD was prepared by high-pressure homogenization combined with freeze-dryer. Morphology and crystal characteristic of GBCCM NC-SD were analyzed. The dissolution and bioavailability evaluation were performed to investigate the feasibility of GBCCM NC-SD by in vitro dissolution and in vivo integrated pharmacokinetic models.Results: After homogenizing for 30 cycles under the pressure of 650 bar and freeze-drying, GBCCM NC-SD with uniform quality would be obtained. The particle size, PDI and zeta potential were found to be 335.9 ± 32.8 nm, 0.29 ± 0.02 and − 28.4 ± 0.7 mV respectively. Based on charged aerosol detector (CAD) technology, a new chromatographic method for simultaneous detection of eight components in GBCCM was developed. In vitro drug release study showed that the cumulative dissolution of FAs and TLs in GBCCM NC-SD increased from 12.77% to 52.92% (P < 0.01) and 90.91% to 99.21% (P < 0.05) respectively. In comparison with physical mixture of GBCCM and stabilizer (PM), the integrated pharmacokinetics AUC0-t of FAs and TLs in GBCCM NC-SD were significantly increased (P < 0.05), and the T1/2 of TLs was also significantly prolonged (P < 0.05).Conclusion: This study demonstrated that novel GBCCM NC-SD was prepared using Polyvinylpyrrolidone K30 (PVP K30) and Sodium dodecyl sulfate (SDS) as a synergetic stabilizer and also provided a feasible way to improve the dissolution and oral bioavailability of poorly soluble candidate antihypertensive drugs.Keywords: Ginkgo biloba, flavonoid aglycones, terpenoid lactones, nanocrystalline solid dispersion, integrated pharmacokinetics, charged aerosol detector

Lipid nanoparticles (LNPs) are widely used as delivery systems for mRNA vaccines. The stability and bilayer fluidity of LNPs are determined by the properties and contents of the various lipids used in the formulation system, and the delivery efficiency of LNPs largely depends on the lipid composition. For the quality control of such vaccines, here we developed and validated an HPLC-CAD method to identify and determine the contents of four lipids in an LNP-encapsulated COVID-19 mRNA vaccine to support lipid analysis for the development of new drugs and vaccines. [ABSTRACT FROM AUTHOR]

An alternative to the time-consuming and error-prone pharmacopoeial gas chromatography method for the analysis of fatty acids (FAs) is urgently needed. The objective was therefore to propose a robust liquid chromatography method with charged aerosol detection for the analysis of polysorbate 80 (PS80) and magnesium stearate. FAs with different numbers of carbon atoms in the chain necessitated the use of a gradient method with a Hypersil Gold C18 column and acetonitrile as organic modifier. The risk-based Analytical Quality by Design approach was applied to define the Method Operable Design Region (MODR). Formic acid concentration, initial and final percentages of acetonitrile, gradient elution time, column temperature, and mobile phase flow rate were identified as critical method parameters (CMPs). The initial and final percentages of acetonitrile were fixed while the remaining CMPs were fine-tuned using response surface methodology. Critical method attributes included the baseline separation of adjacent peaks (α-linolenic and myristic acid, and oleic and petroselinic acid) and the retention factor of the last compound eluted, stearic acid. The MODR was calculated by Monte Carlo simulations with a probability equal or greater than 90%. Finally, the column temperature was set at 33 °C, the flow rate was 0.575 mL/min, and acetonitrile linearly increased from 70 to 80% (v/v) within 14.2 min. [ABSTRACT FROM AUTHOR]

In this study, we discuss the origin of the slightly increased response of the charged aerosol detector when low‐concentration polar drugs formulated with sodium chloride are analyzed by hydrophilic interaction liquid chromatography coupled to the charged aerosol detector. In the case of tromethamine mixed with saline solutions, we investigated several levels including the mobile phase, sample matrix, and detection. We show that the analysis of the rich‐salted sample results in both interactions with the mobile phase modifiers and the stationary phase during the run time. With 150 mM NaCl as a compounding solution, a slight increase in the tromethamine peak area was observed (<5.5%). Our study suggests that chloride ions in excess sequentially interact firstly with the counterions from the organic modifiers and secondly with the analyte via the stationary phase and the contribution of hydrophilic interaction liquid chromatography retention mechanisms. Because of these effects, the hydrophilic interaction liquid chromatography‐charged aerosol detector analysis of drugs in saline solutions requires particular attention, and a correction factor for quantitative purposes that accounts for formulation ions remains appropriate. [ABSTRACT FROM AUTHOR]

The sweeteners are separated by high performance liquid chromatography (HPLC) with 5 mmol/L ammonium formate-acetonitrile gradient elution and quantified by charged aerosol detector (CAD) to establish a method for the simultaneous determination of eight artificial sweeteners in food by HPLC-CAD. The linearity of acesulfame, sodium saccharin, cyclamate, sucralose, aspartame, alitame, advantame and neotame in the range is good, and the correlation coefficient is above 0. 999. The limit of detection and quantitation is 5~30 μg/L and 20~150 μg/L, respectively. The recovery rates are 88. 5% to 102. 8%, and the relative standard deviations are less than 2. 16%. The method is simple, rapid, sensitive and reproducible, and can be used for the detection of 8 sweeteners in food. [ABSTRACT FROM AUTHOR]

The authenticity of coffee beans was addressed in this study using an analytical method with minimal sample preparation to achieve simple oil extraction and through the implementation of cost-effective equipment. For this purpose, methods using UHPLC with CAD and FLD detectors were applied to detect triglycerides and tocopherols in coffee, respectively. The coffee samples included two main varieties: Arabica from Brazil, Colombia, Ethiopia, and Uganda, as well as the Robusta variety from Cambodia, Guatemala, India, and Vietnam. The samples were either in their green state or subjected to different roasting levels. The used methods successfully distinguished the Arabica and Robusta variants targeted in this study based on their tocopherols and TAG profiles, with the latter being particularly effective for discriminating the origins of the Arabica coffee, while tocopherols excelled at differentiating the origin of the Robusta coffee. TAGs and tocopherols were not affected by the type of roasting, from medium to very dark, suggesting it is possible to distinguish between coffee varieties independently from their degree of roasting. The obtained results hold valuable implications for future research regarding coffee fraud and authenticity.

Etimicin is a typical aminoglycoside antibiotic (AG). High performance liquid chromatography-evaporation light scattering detector (HPLC-ELSD) method is a commonly used method for determining impurities in Etimicin. However, due to the poor reproducibility, low sensitivity and narrow linear range of the ELSD, high-throughput quantitative analysis of impurities in Etimicin currently poses a challenge. In this study, a sensitive method using hydrophilic interaction liquid chromatography coupled with charged aerosol detector (HILIC-CAD) was developed for the analysis of the impurities in Etimicin. The liquid phase conditions for determination impurities in Etimicin were optimized using Box Behnken design (BBD) and response surface methodology (RSM), resulting in satisfactory separation and optimal CAD output signal. We also studied the influence of CAD parameters on the signal-to-noise ratio and linearity of Etimicin and its impurities. This method has also been proven to be effective in separating impurities from two other typical AGs, Isepamicin and Amikacin. In the method validation, the coefficient of determination (R2) of Etimicin, Isepamicin and Amikacin and their impurities were all greater than 0.999, within the range of 0.5–50 μg/mL. The average recoveries of the impurities of three typical AGs were 99.03 %-101.22 %, RSDs all were less than 2.5 % for intra-day and inter-day precision, with good precision and accuracy. The developed HILIC-CAD quantification method was sensitive, accurate and highly selective for quantitative analysis of impurities in the AGs without need ion-pairing reagents, which is ensure the public medication safety. The method is first reported application of HILIC-CAD method for quantitative analysis of the impurities in AGs. • A HILIC system for separation of impurities in Etimicin was developed. • Establish a CAD method for determination impurities without UV absorption. • Liquid phase was optimized for good separation and output signal of CAD by RSM. • The CAD parameters were optimized for good S/N and linearity. [ABSTRACT FROM AUTHOR]

• Ionisation suppression is a problem for mass spectrometry in biogeochemistry. • A multi detector approach and chromatographic separation adds analytical value. • A code is presented, allowing assignment of formulas and alignment of eluting peaks. Ionisation suppression is a persistent issue in electrospray ionisation mass spectrometry, which decreases the signal of co-eluting analytes. In non-targeted analysis, where analyte and organic matrix identity is unknown, this poses a very challenging analytical problem when it comes to quantitatively assessing differences between samples, including in a compositional sense. In this study, I demonstrate the problems that arise due to ionisation suppression using a very simple sample mixing scheme between a fresh, metabolite rich sample (a leaf leachate) and a forest pond water. Samples were analysed after solid phase extraction on Agilent PPL and using high performance liquid chromatography coupled to electrospray ionisation – Orbitrap mass spectrometry, charged aerosol detector and diode array detector, the latter two allowing quantification of eluting material. I found that more than half of the well-resolved analytes expected to be present (at equal concentration) were completely lost from detection after mixing with pond water DOM. The average recovery of analytical signal (i.e., the signal weighted average), was about 50%, and was highly variable between analytes. Ionisation suppression also affected the signal obtained from the geochemical background DOM, and material recovery decreased slightly when mixing samples and extracting at a higher volume on PPL. Overall, the results showed that ionisation suppression is an extremely important problem for comparison of biogeochemical samples, even when only considering presence and absence of detected features. A multi detector approach and liquid chromatographic separation adds great value in comparison to use of only high resolution mass spectrometry (in direct infusion mode). [ABSTRACT FROM AUTHOR]

• Systematic HILIC assay development of polar analytes remains a challenge. • A new, automated HILIC-DAD-CAD method development workflow for polar analytes. • Screening of 12 columns with sub-2.7 µm fully and superficially porous particles. • Evaluation of different eluent pH and column equilibration time. • Diverse compounds and real-life common pharmaceutical examples were explored. The pharmaceutical industry is rapidly advancing toward new drug modalities, necessitating the development of advanced analytical strategies for effective, meaningful, and reliable assays. Hydrophilic Interaction Chromatography (HILIC) is a powerful technique for the analysis of polar analytes. Despite being a well-established technique, HILIC method development can be laborious owing to the multiple factors that affect the separation mechanism, such as the selection of stationary phase chemistry, mobile phase eluents, and optimization of column equilibration time. Herein, we introduce a new automated multicolumn and multi-eluent screening workflow that streamlines the development of new HILIC assays, circumventing the existing tedious 'hit-or-miss' approach. A total of 12 complementary columns packed with sub-2 µm fully porous and 2.7 µm superficially porous particles operated on readily available ultra-high pressure liquid chromatography (UHPLC) instrumentation across a diverse set of commercially available polar stationary phases were investigated. Different mobile phases with pH ranging from pH 3 to 9 were evaluated using different organic modifiers. The gradient and column re-equilibration were judiciously set to ensure a reliable assay screening framework that indicates promising conditions for subsequent method optimization to achieve resolution of challenging mixtures. This UHPLC screening system is coupled with a diode array and charged aerosol detectors (DAD, CAD and mass spectrometry) to ensure versatile detection for a variety of compounds. This fast-screening platform lays the foundation for a convenient generic workflow, accelerating the pace of HILIC method development and transfer across both academic and industrial sectors. [ABSTRACT FROM AUTHOR]

The P. heterophylla and its adulterants were identified by HPLC-CAD fingerprint of sucrose and oligosaccharides in P. heterophylla. The improved quantitative analysis of multi-components with a single marker (iQAMS) was further established for simultaneous determinations of sucrose and oligosaccharides in P. heterophylla. The HPLC-CAD fingerprint and similarity coefficients between P. heterophylla and its adulterants showed significant differences. The relative errors (REs) between iQAMS method and external standard method (ESM) were below 3.00%, but significant difference was shown between iQAMS (different marker for whole program with gradient elution) and QAMS (one marker for whole program with gradient elution), indicating that QAMS method should be improved, especially for gradient elution which influence the response of analytes. The accuracy, precision, reproducibility, and stability of this method were validated which exhibited satisfactory results, indicating that iQAMS method could be used for quantitative analysis of sucrose and oligosaccharides in P. heterophylla instead of ESM. The iQAMS combined with HPLC-CAD fingerprint could be used to determine the content of each oligosaccharide, and it can be used for quality control of P. heterophylla. • P. heterophylla and its adulterants were firstly rapid identification by HPLC-CAD fingerprint. • A novel method, HPLC-CAD combined with improved QAMS, was developed for P. heterophylla analysis. • Total contents of sucrose and oligosaccharides were quantified by improved QAMS with PHO DP3–1 and PHO DP4. • The developed QAMS can improve the accuracy of HPLC quantification with gradient elution in the absence of reference standards. [ABSTRACT FROM AUTHOR]

Endemic in more than 90 countries and territories, malaria is the most widely, populational, and geographically, parasitic disease in the world. Plasmodium sp. resistance to available drugs is one of the biggest problems for malaria eradication. In this study, we develop a method for the simultaneous determination of two new derivatives of betulinic and ursolic acids with antimalarial activity designated 3-O-butanoylbetulinic and 3-O-butanoylursolic acids. An analytical method was developed by high-performance liquid chromatography coupled, in series, to ultraviolet (UV) and charged aerosol (CAD) detectors. The chromatographic system, operated isocratically by reversed-phase, consisted in a mobile phase composed of acetonitrile: water pH 3.0 adjusted with formic acid (85:15, v/v), flow rate of 1.2 mL/min and a PhenoSphere Next octadecylsilane column (250 mm x 4.6 mm, 5 μm particle size). Chromatograms were recorded simultaneously in UV and CAD, at a concentration of 50 µg mL-1, an injection volume of 20 μL at a controlled temperature of 50 °C. The method was found to be selective, linear (r > 0.99), precise (RSD < 2.0%), accurate, and robust for both analytes, and considered statistically validated, and can be applied to the identification and quantification of these new drug candidates.

Lipid nanoparticles (LNPs) are widely used as delivery systems for mRNA vaccines. The stability and bilayer fluidity of LNPs are determined by the properties and contents of the various lipids used in the formulation system, and the delivery efficiency of LNPs largely depends on the lipid composition. For the quality control of such vaccines, here we developed and validated an HPLC-CAD method to identify and determine the contents of four lipids in an LNP-encapsulated COVID-19 mRNA vaccine to support lipid analysis for the development of new drugs and vaccines.

To take advantage of the charged aerosol detector (CAD) for sensitive LC analysis of analytes with weak chromophore, the volatility of the entire mobile phase is a prerequisite. Therefore, it is not feasible to use common non-volatile ion-pairing reagents such as tetrabutylammonium hydroxide for the analysis of polar, acidic amino acids.This case study presents a possible procedure for transferring an ion pair chromatography to an HPLCCAD method using the example of carbocisteine and its two main degradation products, carbocisteine sulfoxide and carbocisteine lactam. In screening experiments, substitution by various volatile alkylamines resulted in inferior chromatographic separation. As an alternative, mixed-mode chromatography using a column with strong anion exchange functionalities and a mobile phase containing 12 mM formic acid and 2 mM trifluoroacetic acid, led to a selectivity equivalent to ion pair chromatography with tetrabutylammonium hydroxide. A change in the level of background noise generated by non-volatile impurities eluting from the column during measurements – often called column bleeding – invalidated the settings predicted from response surface methodology experiments in terms of modelling chromatographic selectivity and CAD sensitivity, and a reduction of the acetonitrile ratio to 22% (v/v) was required. At a flow rate of 1.2 mL/min and an evaporation temperature of 65 °C, the experimentally determined LOQs of both degradation products were below 50 ng on column. The combination of mixed-mode chromatography with CAD offers a viable alternative to ion pair chromatography with UV detection in the analysis of acidic analytes with a weak chromophore such as amino acids and impurities thereof.

The objective of the study is to develop a quick and simultaneous analysis system for the dissolution of the active pharmaceutical ingredient (API) and the formulation excipient in samples from the dissolution test by UHPLC using the charged aerosol and PDA detectors. The combination of two columns for size-exclusion chromatography (SEC) and the equipment of the charged aerosol detector allowed the quick determination of various water-soluble polymers. Three model sustained-release tablets, each containing a different API of different water solubility (propranolol (soluble), ranitidine (very soluble), and cilostazol (practically insoluble)), were prepared from polyethylene oxide (PEO) matrix to verify the applicability and utility of the analysis system. The dissolution of propranolol was the same as that of PEO, indicating that the diffusion rate of propranolol was consistent with the erosion rate of the PEO and that the dissolution of PRO was based on diffusion. Ranitidine was released faster than PEO, suggesting that ranitidine was diffused through the gel layer of PEO early upon contact with the dissolution medium and before PEO gel erosion. Cilostazol was released slower as compared to PEO, indicating that cilostazol dissolution was based on the polymer's erosion. These results suggested that the analysis system developed in this study is a precise and valid tool to study the dissolution behavior of both APIs and excipients. Optimization of the SEC column for the appropriate separation of APIs and excipients makes the analysis system more efficient and convenient to study the drug release mechanisms and to design formulations. [ABSTRACT FROM AUTHOR]

• A versatile economic strategy was proposed for SMF research. • A high-throughput CAD method for 50 compounds characterization was established. • This method showed potency to distinguish the authenticity of raw materials used in Shengmai preparations. • Components transferring information of SMF from raw materials to preparations were revealed, which can guide the quality improvement of SMF. Shengmai Formula (SMF), a classic formula in treating Qi-Yin deficiency, is composed of Ginseng Radix et Rhizoma Rubra (GRR) , Ophiopogon Radix (OR), and Schisandra chinensis Fructus (SC), and has been developed into various dosage forms including Shengmai Yin Oral Liquid (SMY), Shengmai Capsules (SMC), and Shengmai Injection (SMI). The pharmacological effects of compound Chinese medicine are attributed to the integration of multiple components. Yet the quality criteria of SMF are limited to monitoring schisandrol A or ginsenosides Rg1 and Re, but none for OR. Since the complexity of raw materials and preparations, establishing a economical and unified method for SMF is challenging. It is urgent to simultaneously quantify multiple components with different structures using a universal method for quality control of SMF. Charged aerosol detector (CAD) overcame the above shortcomings owing to its characteristics of high responsiveness, nondiscrimination, and low cost. We aimed to establish a versatile analysis strategy using HPLC–CAD for simultaneously quantifying the structurally diverse markers in quality control of SMF from raw materials to preparations. By optimizing the column, mobile phase, column temperature, flow rate, and CAD parameters, a HPLC-CAD method that integrated multi-component characterization, authenticity identification, transfer information of raw materials and quantitative determination of Shengmai preparations was established. In total 50 components from SMF were characterized (28 in GRR, 13 in SC, and 9 in OR). The differences in raw materials between species of SC and Schisandrae sphenantherae Fructus (SS), processing methods of Ginseng Radix (GR) and GRR, and locations of OR from Sichuan (ORS) and Zhejiang (ORZ) were compared. Fourteen components in 19 batches of SMY, SMC and SMI from different manufacturers were quantified, including 11 ginsenosides and 3 lignans. The multivariate statistical analysis results further suggested that Rb1, Rg1 and Ro were the main differences among Shengmai preparations. The established versatile analysis strategy based on HPLC–CAD was proven sensitive, simple, convenient, overcoming the discriminatory effect of UV detector, revealing the composition and transfer information of SMF and applicable for authentication of the ingredient herbs and improving the quality of Shengmai preparations. [Display omitted] [ABSTRACT FROM AUTHOR]

In addition to degradation products, impurities, and exogenous contaminants, industries such as pharmaceutical, food, and others must concern themselves with leachables. These chemicals can derive from containers and closures or migrate from labels or secondary containers and packaging to make their way into products. Identification and quantification of extractables (potential leachables) and leachables, typically trace level analytes, is a regulatory expectation intended to ensure consumer safety and product fidelity. Mass spectrometry and related techniques have played a significant role in the analysis of extractables and leachables (E&L). This review provides an overview of how mass spectrometry is used for E&L studies, primarily in the context of the pharmaceutical industry. This review includes work flows, examples of how identification and quantification is done, and the importance of orthogonal data from several different detectors. E&L analyses are driven by the need for consumer safety. These studies are expected to expand in existing areas (e.g., food, textiles, toys, etc.) and into new, currently unregulated product areas. Thus, this topic is of interest to audiences beyond just the pharmaceutical and health care industries. Finally, the potential of universal detector approaches used in other areas is suggested as an opportunity to drive E&L research progress in this arguably understudied, under‐published realm. [ABSTRACT FROM AUTHOR]

Zidebactam (ZID), a novel β-lactam enhancer drug being developed to treat infections caused by Gram-negative bacteria, currently is in phase III clinical development. Two ionic impurities observed in liquid chromatography with charged aerosol detector (CAD) analysis were identified through liquid-chromatography mass spectrometry (LC–MS) as sulfate (SO4−2) and monomethyl sulfate (CH3OSO3−1, MMS). There genesis was attributed to the use of pyridine sulfur trioxide as a reagent in ZID synthesis. A new chromatographic method using mixed-mode stationary phase and CAD was developed and validated. The separation of ionic impurities was achieved on Obelisc-N column using buffer gradient. The new method was found to be simple, specific, sensitive, precise, accurate and robust for controlling these impurities in new drug substance. Accuracy of the method was verified by comparing the results with that of ion chromatography (IC) with conductivity detector. The IC method was employed to monitor the impurities in ZID drug substance used for clinical trials and stability analysis. [ABSTRACT FROM AUTHOR]

This study utilised response surface methodology to optimise the conditions for the extraction of A. rugosa seeds oil (ARO). Single–factor experiment and response surface methodology (RSM) were performed to identify the extraction time, liquid–solid ratio and extraction temperature that provided the highest yield of ARO. The optimal extraction time, liquid–solid ratio and extraction temperature were 8 h, 4:1 mL/g and 55 °C. The fatty acids (FAs) content and oil yield obtained through the optimised impregnation–extraction process were 19.67 mg/g and 32.1%. These values matched well with the predicted values. Linolenic acid was identified to be the main active ingredient of ARO. The high–performance liquid chromatography–charged aerosol detection method presented here is fast and does not require derivatisation. Therefore, it could be used to quantitatively analyse the FAs present in ARO and applied to detect compounds with low or no ultraviolet response. [ABSTRACT FROM AUTHOR]

In this study, a quantitative structure-property relationship model was built in order to link molecular descriptors and chromatographic parameters as inputs towards CAD responsiveness. Aminoglycoside antibiotics, sugars, and acetylated amino sugars, which all lack a UV/vis chromophore, were selected as model substances due to their polar nature that represents a challenge in generating a CAD response. Acetone, PFPA, flow rate, data rate, filter constant, SM5_B(s), ATS7s, SpMin1_Bh(v), Mor09e, Mor22e, E1u, R7v+, and VP as the most influential inputs were correlated with the CAD response by virtue of ANN applying a backpropagation learning rule. External validation on previously unseen substances showed that the developed 13-6-3-1 ANN model could be used for CAD response prediction across the examined experimental domain reliably (R2 0.989 and RMSE 0.036). The obtained network was used to reveal CAD response correlations. The impact of organic modifier content and flow rate was in accordance with the theory of the detector's functioning. Additionally, the significance of SpMin1_Bh(v) aided in emphasizing the often neglected surface-dependent CAD character, while the importance of Mor22e as a molecular descriptor accentuated its dependency on the number of electronegative atoms taking part in charging the formed particles. The significance of PFPA demonstrated the possibility of using evaporative chaotropic reagents in CAD response improvement when dealing with highly polar substances that act as kosmotropes. The network was also used in identifying possible interactions between the most significant inputs. A joint effect of PFPA and acetone was shown, representing a good starting point for further investigation with different and, especially, eco-friendly organic solvents and chaotropic agents in the routine application of CAD. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A simple, low-cost and reliable method for analysis of 13 components was developed. • UV/CAD method for the first time in the analysis of Astragali Radix (AR) was used. • The performance of UV and CAD were systematically compared. • Astragaloside III and astragaloside IV can be the chemical markers of AR. Abstract To identify more chemical markers for improving the quality standard and evaluate producing areas differentiation of Astragali Radix (AR), a simple, low-cost and reliable chromatography method based on a high performance liquid chromatography (HPLC) coupled with ultraviolet (UV) detector and charged aerosol detector (CAD) for separation of 13 major chemical components, including 8 flavonoids and 5 astragalosides in AR extract, was developed. The contents of 13 compounds in total of 27 herb samples, collected from different cultivating regions, were determined and compared. Moreover, chemometric analysis techniques with principal component constituent analysis (PCA) and cluster analysis (CA) were performed to discriminate the samples from different producing areas. As a result, an obvious linkage between the content of components and collecting areas was found. Results showed that the content of astragaloside III and astragaloside IV could be used to differentiate samples collected from Northeast China, Inner Mongolia and Shanxi Province, suggesting that they should be added as the chemical marker for further investigation on the pharmacological actions and the quality control of AR. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A mixed-mode chromatography method was applied to the quality control of PAMA injection. • The main components Asp, K+, Mg2+ and the impurity Na+ were evaluated simultaneously. • Several single factor experiments analysis were used to optimize the chromatography conditions. Abstract This study describes an analytical method to control the quality of potassium aspartate and magnesium aspartate (PAMA) injection based on the simultaneous detection of the main components (K+, Mg2+ and Asp) and impurities (Na+) using a mixed-mode chromatography coupled with charged aerosol detector. To obtain optimal chromatographic separation, the effects of organic content, column temperature, buffer types, pH and concentrations were evaluated. A Response Surface Methodology (RSM) optimal design was performed after single factor experiment. The mixed-mode HPLC method is proved to be a complementary approach to the conventional ion chromatography (IC). The optimized method was successfully validated and applied to the analysis of Asp, K+, Na+ and Mg2+ in PAMA injection with good specificity, linearity, accuracy, and repeatability. The method would be useful for quality control in PAMA injection and other similar drugs, which can provide references for the analysis of drug quality by enterprises and drug regulatory department. [ABSTRACT FROM AUTHOR]

Today, one of the most popular strategies in drug delivery is the encapsulation of therapeutic agents in supramolecular nanosystems formed from amphiphilic molecules. Synthetic nucleoside-lipids, composed of one nucleoside and lipidic chains, constitute promising new amphiphilic excipients under research in the field of pharmaceutical and biomedical applications. The aim of this work was to study the chromatographic behavior of these nucleoside-lipids in reversed-phase HPLC to establish appropriate chromatographic conditions for their analysis in drug delivery systems. The effect of the stationary phase, the organic solvent, the pH* values, and pH modifier nature of the mobile phase were studied on retention, peak shape, and detection. Good chromatographic performance was achieved on both Syncronis® C18 and Acquity® BEH C18 with mobile phases composed of MeOH/water, 95:5 (v/v) mixtures at apparent pH above 5. Dual detection by diode array detection (DAD) and charged aerosol detection (CAD) was investigated. CAD signal was found to be dependent on the type of pH modifiers added to the mobile phase. In isocratic elution, the same order of magnitude of CAD responses was obtained for the tested nucleoside-lipids. This study led to suitable chromatographic conditions for purity and stability studies of nucleoside-lipids. The purity of the synthetized molecules was established to be superior to 98%. Different stability in organic solvents was noticed depending on nucleoside-lipid structure. This first study will allow quantitative applications to establish loading ratio and encapsulation yield in future drug delivery systems composed of nucleoside-lipid-based assemblies. [ABSTRACT FROM AUTHOR]

Highlights • UHPLC method optimization with improved LOQs and significant time and eluent saving. • CAD parameters' impact on detection limits and linearity was evaluated. • Fatty acids from C 12 to C 18 showing semivolatile characteristics were examined. Abstract The analysis of polysorbate 80 is a challenge because all components lack a chromophore. Here, an ultra-high-performance liquid chromatography system equipped with a charged aerosol detector (UHPLC-CAD) was used to study the effect of systematic variation of the CAD settings, namely evaporation temperature, filter constant and power function value (PFV), on the detector response of fatty acid standards and manufacturing batches of polysorbate. Evaporation temperature and filter constant strongly affect the detection limits described by signal-to-noise (S/N) ratios. Although evaporation temperature can be increased to improve signal to noise ratios, analyte volatility at higher temperatures is an important limiting factor. The PFV was found to be a strong tool for optimizing response linearity, but the optimal PFV differed depending on analyte volatility. Because PFV optimization required some additional measurement time and because double-logarithmic transformation at the default PFV of 1.0 yielded satisfying universal results with less measurement time over a range of two orders of magnitude for every homologue fatty acid from C14 to C18, use of the log-log transformation is the favored linearization strategy. Possible optimization procedures for semi volatile substances are presented. Overall, this new UHPLC method method offers improved detection limits, as well as time savings of over 75% and eluent savings of more than 40% compared to the previously published HPLC-CAD method for polysorbate analysis. [ABSTRACT FROM AUTHOR]

Highlights • CAD with inverse gradient compensation technique was used. • Universal response quantification approach for known and unknown substances. • An analytical parameter to assess applicability of universal approach was defined. • CAD quantification was compared with established reference methods for oligomers. • Sensitivity (LOD) of CAD detection is slightly lower than for detection via UV. Abstract In terms of risk assessment especially for known and unknown substances migrating from food contact materials, quantification without corresponding reference substances currently poses a challenge. In the present study, the opportunity of a universal response quantification approach was evaluated by using a corona charged aerosol detector (CAD) for liquid chromatography combined with inverse gradient compensation. Characteristics of CAD detection in dependence of substance properties were analyzed with 46 randomly chosen reference substances. An almost equal CAD response (±20%) was achieved for non-volatile substances with a molecular weight of minimum 400 g/mol and a vapor pressure of maximum 10−8 Torr. We empirically defined an analytical parameter, Q 50/35 , the quotient of CAD peak areas at CAD evaporator temperatures of 50 °C and 35 °C, to predict the adequacy of the CAD universal response approach for quantification of known and unknown analyte substances. Exemplarily, we applied the CAD universal quantification approach for the determination of extractable oligomers below 1000 g/mol from a variety of food contact polycondensate plastic materials (e.g. polyesters like polyethylene terephthalate, polybutylene terephthalate, Tritan copolyester, polyamides 6, 6.6 and 6 T/6I and polyarylsulfones polyphenylsulfone and polyethersulfone). Quantitative results for in total 44 oligomers out of 11 materials were compared with established material-specific quantification methods using extracted oligomer mixtures as well as individual oligomers isolated from the mixtures. CAD-based quantification results were generally in accordance to published quantification approaches for polyamide oligomers and oligomers from polyarylsulfones. For oligomers extracted and isolated from polyester materials a slight underestimation was determined by CAD universal response approach. In terms of detection limits and accuracy, the universal CAD approach exhibits no advantages compared to established UV-methods, to date. [ABSTRACT FROM AUTHOR]

Abstract: The analysis of topiramate in the presence of its main degradation products is challenging due to the absence of chromophore moieties and their wide range of polarity. Mixed‐mode chromatography has been used in such cases because it combines two or more modes of separation. Charged aerosol detector is also an alternative since its detection is independent of optical properties and analyte ionization. This study is aimed to develop and validate two new stability‐indicating methods by high‐performance liquid chromatography for the main degradation products of topiramate using mixed‐mode chromatography and a charged aerosol detector. Method 1 employed an Acclaim Trinity P1® column (3.0 mm × 150 mm, 2.7 μm) with a mobile phase comprising of 80% ammonium acetate buffer (20 mM, pH 4.0) and 20% methanol at a flow rate of 0.5 mL/min at 35°C. Method 2 utilized a C18 Acclaim 120® column (4.6 mm × 250 mm; 5 μm) with ACN/water (50:50) at a flow rate of 0.6 mL/min at 50°C. Validation of the two methods demonstrated excellent performance with respect to linearity, precision, accuracy, and selectivity. The limits of detection for topiramate, fructose, sulfate, sulfamate, and compound A were 2.97, 12.08, 4.02, 13.91, and 3.94 μg/mL, respectively. [ABSTRACT FROM AUTHOR]

Phospholipids are an important class of lipids in cell membranes and food. Several high-performance liquid chromatography (HPLC) methods have been developed to analyze phospholipids at the molecular species level. We developed a two-dimensional HPLC system with a charged aerosol detector and mass spectrometry (MS) to analyze phosphatidylethanolamine (PE), phosphatidylcholine (PC), and their plasmalogens (pls) extracted from food materials. Accordingly, the phospholipid molecular species can be analyzed in a single step despite using smaller samples. We confirmed that chromatogram peaks from soybean lecithin are mostly baseline separated, assigned, and quantified (24 molecular species for PE and 27 for PC). In addition, it was confirmed that chromatograms of lipids extracted from chicken breast meat include plasmalogen peaks. The PE fraction in lipids extracted from chicken breast meat contained 17 types of ethanolamine plasmalogens, corresponding to approximately 57% of the total by weight. The PC fraction contained only four choline plasmalogens, corresponding to approximately 11% of the total weight. The composition of the pls-PC molecular species differed from that of pls-PEs. The polyunsaturated fatty acids connected at the sn -2 positions of the pls-PEs consisted of 20.5% 20:4 fatty acid and were independent of the carbon chain at the sn -1 position. However, the 18:1 fatty acid at the sn -2 position was dependent on the carbon chain at the sn -1 position. [ABSTRACT FROM AUTHOR]

Roflumilast is a phosphodiesterase type 4 inhibitor that is administered orally as a long-term, in the clinical treatment of chronic obstructive pulmonary disease and asthma. Launched in 2010 for the European market, it currently does not have an official monograph. Here, a reproducible gradient RP-HPLC method was developed and validated for the separation and determination of Roflumilast in the presence of its six major degradation products. Separation was performed on a C18 analytical column (250 × 4.6 mm, 5 µm) with a mobile phase-A of ACN and a phase-B of ammonium acetate buffer (5 mM, pH 4.2) containing triethylamine (0.5% v/v). The most effective RP-HPLC gradient program was determined to be 0/80, 35/10, 36/80, 40/80 (time in minutes/% mobile phase-B). The flow rate was 1.0 ml/min and the column temperature was 25°C. The success of separation of the degradation products with different chemical characteristics was obtained by extending the time of the gradient, changing the proportion of the mobile phases and increasing the velocity of the flow. Two detectors were evaluated for the identification of degradation products and Roflumilast: a diode-arrary detector and a charged aerosol detector. The inability of the charged aerosol detector to dectect one of the six degradation products indicated that the method developed with RP-HPLC and the diode-array detector was more suitable for Roflumilast analysis. The method was validated according to specificity, linearity, LOD, LOQ, accuracy, precision and robustness. [ABSTRACT FROM AUTHOR]

In the present study, a novel ultra high-pressure liquid chromatography method using charged aerosol detector (UHPLC-CAD) with an inverse-gradient solvent compensation has been developed for the analysis of triacylglycerols (TAGs) in extra-virgin olive oil. Using a gradient method with a superficially porous particles column, an improved separation of TAGs was obtained, with notably shortening of both solvent consumption and analysis time, in comparison with the IOC official method for ECN 42 analysis. Furthermore, an almost baseline separation of trilinolein was obtained. CAD provides good linearity (R 2  > 0.999) in the range of 0.05–10 μg of trilinolein injected on column as well as uniformity of response factor for different TAG molecular species. Finally, the proposed UHPLC-CAD methodology has been successfully applied to the determination of trilinolein in low-linoleic acid extra-virgin olive oil mixed in different proportions with high-oleic sunflower oil, palm olein and a mix of them at different percentages of 2, 4, 6, 8 and 10% (w/w). Good linearity was achieved in all the three blends with correlation coefficients greater than 0.975 in all cases. [ABSTRACT FROM AUTHOR]

• Optimized HPLC CAD method to simultaneously quantify different lipids in LNPs. • Application of analytical quality by design (AQbD) approach with risk assessment. • Method operable design region (MODR) established using monte carlo simulation. • HPLC CAD method validated according to the ICH guidelines. Since lipid nanoparticles (LNP) have emerged as a potent drug delivery system, the objective of this study was to develop and optimize a robust high-performance liquid chromatography with charged aerosol detectors (HPLC CAD) method to simultaneously quantify different lipids in LNPs using the analytical quality by design (AQbD) approach. After defining analytical target profile (ATP), critical method attributes (CMAs) were established as a resolution between the closely eluting lipid peaks and the total analysis time. Thus, potential high-risk method parameters were identified through the initial risk assessment. These parameters were screened using Plackett–Burman design, and three critical method parameters (CMPs)—MeOH ratio, flow rate, and column temperature—were selected for further optimization. Box–Behnken design was employed to develop the quadratic models that explain the relationship between the CMPs and CMAs and to determine the optimal operating conditions. Moreover, to ensure the robustness of the developed method, a method operable design region (MODR) was established using the Monte Carlo simulation. The MODR was identified within the probability map, where the risk of failure to achieve the desired CMAs was less than 1%. The optimized method was validated according to the ICH guidelines (linearity: R2 > 0.995, accuracy: 97.15–100.48% recovery, precision: RSD < 5%) and successfully applied for the analysis of the lipid in the LNP samples. The development of the analytical method to quantify the lipids is essential for the formulation development and quality control of LNP-based drugs since the potency of LNPs is significantly dependent on the compositions and contents of the lipids in the formation. [ABSTRACT FROM AUTHOR]

• A universal MHC-2DLC/CAD method was constructed following the MCSA strategy. • Eight consecutive cutting achieved the separation of 16 ginsenosides within 85 min. • The chromophore-free ginsenoside like 24(R)-p-F11 got sensitively detected. • The contents of 16 ginsenosides simultaneously from 28 CPMs were determined. • Quantitative evaluation of different ginseng from multiple CPMs was enabled. For quality control of Chinese patent medicines (CPMs) containing the same herbal medicine or different herbal medicines that have similar chemical composition, current ″one standard for one species″ research mode leads to poor universality of the analytical approaches unfavorable to discriminate easily confused species. Herein, we were aimed to elaborate a multiple heart-cutting two-dimensional liquid chromatography/charged aerosol detector (MHC-2DLC/CAD) approach to quantitatively assess ginseng from multiple CPMs. Targeting baseline resolution of 16 ginsenosides (noto-R1/Rg1/Re/Rf/Ra2/Rb1/Rc/Ro/Rb2/Rb3/Rd/Rh1/Rg2/Rg3/Rg3(R)/24(R)-p-F11), experiments were conducted to optimize key parameters and validate its performance. A Poroshell 120 EC-C18 column and an XBridge Shield RP18 column were separately utilized in the first-dimensional (1D) and the second-dimensional (2D) chromatography. Eight consecutive cuttings could achieve good separation of 16 ginsenosides within 85 min. The developed MHC-2DLC/CAD method showed good linearity (R 2 > 0.999), repeatability (RSD < 6.73%), stability (RSD < 5.63%), inter- and intra-day precision (RSD < 5.57%), recovery (93.76–111.14%), and the limit of detection (LOD) and limit of quantification (LOQ) varied between 0.45–2.37 ng and 0.96–4.71 ng, respectively. We applied it to the content determination of 16 ginsenosides simultaneously from 28 different ginseng-containing CPMs, which unveiled the ginsenoside content difference among the tested CPMs, and gave useful information to discriminate ginseng in the preparation samples, as well. The MHC-2DLC/CAD approach exhibited advantages of high specificity, good separation ability, and relative high analysis efficiency, which also justified the feasibility of our proposed ″Monomethod Characterization of Structure Analogs″ strategy in quality evaluation of diverse CPMs that contained different ginseng. [ABSTRACT FROM AUTHOR]

Purpose: The analysis of products which contain synthetic cannabinoids (SCs) is very challenging due to their diversity and rapidly changing SC structures, variable herbal matrices and, above all, inaccessibility of reference standards. Therefore, the aim of this study was to develop a method which allows quantification of SCs' contents in herbal blends without their reference standards. Methods: Identification of SCs was performed using liquid chromatography -high-resolution tandem mass spectrometry with a quadrupole time-of-flight analyser (LC -QTOF-MS/MS). A liquid chromatography-charged aerosol detection (LC -CAD) method with unified calibration for the quantification of SCs was developed and validated. Two available reference standards were used as universal standards. Quantitative analysis using a nuclear magnetic resonance spectroscopy method was also performed to externally validate the developed LC -CAD method. Results: All peaks of SCs observed in LC -CAD chromatograms were identified by LC -QTOF-MS/MS. Validation data and results from a CAD response evaluation indicated that the elaborated quantitative method was sufficiently accurate for the determination of SCs belonging to various chemical families. The LC -CAD method turned out to be very flexible, because it was successfully applied for the analysis of 19 herbal products. Conclusions: In this study, methods which enable identification and quantification of currently known SCs as well as novel unknown derivatives without their reference standards were developed. These methods can be applied to the control of suspect SC products and may support the risk assessment of SC presence on the market. To our knowledge, this is the first trial to use LC-CAD for unified quantification of SCs without their reference standards. [ABSTRACT FROM AUTHOR]

Psoraleae Fructus is one of the most popular traditional Chinese medicines. Coumarins, flavonoids, and meroterpenes are the main contributors to the biological activity of Psoraleae Fructus. In this study, a new method for the quality control of Psoraleae Fructus was developed, through the quantitative analysis of multicomponents by single marker with diode array detector. Thirteen components, including psoralenoside, isopsoralenoside, psoralen, isopsoralen, psoralidin, neobavaisoflavone, bavachin, corylin, isobavachalcone, corylifol A, bavachinin, bavachalcone, and bakuchiol were rapidly separated and identified within 12 min by the newly developed method. The feasibility and reliability of this method were corroborated. The method was also compared to the external standard method and detection by corona charged aerosol detector. The results of percent difference (%) and cos (θ) have shown that there were no significant differences observed between the quantitative analysis of multicomponents by single marker and external standard method analyses; psoralen and isopsoralen were undetectable with the corona charged aerosol detector due to their but the sensitivity for all the compounds except bakuchiol detected by corona charged aerosol detector are higher than those obtained by diode array detector. In addition, the newly method developed was applied to the quality evaluation of Chinese patent medicines containing Psoraleae Fructus. [ABSTRACT FROM AUTHOR]

One important challenge in lipid class analysis is to develop a method suitable or, at least adaptable, for a vast diversity of samples. In the current study, an improved normal-phase liquid chromatography (NPLC) method allowed analyzing the lipid classes present in mammalian, vegetable as well as microorganism (yeast and bacteria) lipid samples. The method effectively separated 30 lipid classes or subclasses with a special focus on medium polarity lipids. The separation was carried out with bare silica stationary phase and was coupled to evaporative light scattering detection (ELSD), charged aerosol detection (Corona-CAD ® ) and mass spectrometry. Solutions are provided to circumvent technical issues (such as pumping solvents of low viscosity, solvent purity, rinsing step). The influence of mobile phase composition and addition of ionic modifiers on the chromatographic behavior of particular lipid classes is documented. A comparison between ELSD and Corona-CAD ® confirmed the interest of this later detector for samples with a wide range of concentration of different lipids. Three common atmospheric pressure ionization interfaces were used for coupling the NPLC separation to a LTQ Velos Pro ® mass spectrometer. The comparison of the chromatographic profiles showed that atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) are both suitable to detect the different lipid classes whereas APPI allows a better sensitivity for lipids at low-concentration. [ABSTRACT FROM AUTHOR]

Our research aimed to optimize the oil extraction process and determine the fatty acids in Brucea javanica (L.) Merr. seeds. The extraction technology was optimized using response surface methodology. A Box-Behnken design was employed to investigate the effects of three independent variables on an ultrasonic-assisted extraction technique, namely, sonication time (X1: 20-40 min), liquid-solid ratio (X2: 16:1 mL/g-24:1 mL/g), and ethanol concentration (X3: 90%-100%). The optimum conditions of sonication time, liquid-solid ratio, and ethanol concentration were 40 min, 24:1 mL/g, and 100%, respectively. The content of fatty acids and the oil yield were 14.64 mg/g and 16.87%, respectively, which match well with the predicted models. The optimum number of extraction times was eventually identified as two. A new rapid method for the qualitative and quantitative analysis of the fatty acids of B. javanica (L.) Merr. seed oil using HPLC with a charged aerosol detector was described. The fatty acid contents of 14 batches of B. javanica (L.) Merr. seed oil were determined, and the relevance and difference were analyzed by fingerprint analysis. The fingerprint has five common peaks, and the similarity was greater than 0.991. HPLC analysis represents a specialized and rational approach for the quality identification and comprehensive evaluation of B. javanica (L.) Merr. seed oils. [ABSTRACT FROM AUTHOR]

Two new stability-indicating liquid chromatographic methods using two detectors, an ultraviolet (UV) and a charged aerosol detector (CAD) simultaneously connected in series were validated for the assessment of lisdexamfetamine dimesylate (LDX) in capsule. The method was optimized and the influence of individual parameters on UV and CAD response and sensitivity was studied. Chromatography was performed on a Zorbax CN column (250 mm × 4.6 mm, 5 μm) in an isocratic elution mode, using acetonitrile and 20 mM ammonium formate at pH 4.0 (50:50, v/v) as mobile phase and UV detection at 207 nm. The developed method was validated according to ICH guidelines and the parameters’ specificity, limit of detection, limit of quantitation, linearity, accuracy, precision and robustness were evaluated. CAD is designated to be a non-linear detector in a wide dynamic range, however, the method was linear over the concentration range of 70–130 μg mL−1 in both detectors. The method was precise and accurate. Robustness study was performed by a Plackett–Burman design, delivering results within the acceptable range. Neither the excipients nor the degradation products showed interference in the method after studies of specificity as well as under stress conditions. The results of the LC-UV and LC-CAD methods were statistically compared through ANOVA and showed no significant difference (p > 0.05). Both proposed methods could be considered interchangeable and stability-indicating, and can be applied as an appropriate quality control tool for routine analysis of LDX in capsule.

Increasing demand for L-arginine by the food and pharmaceutical industries has sparked the search for sustainable ways of producing it. Microbial fermentation offers a suitable alternative; however, monitoring of arginine production and carbon source uptake during fermentation, requires simple and reliable quantitative methods compatible with the fermentation medium. Two methods for the simultaneous quantification of arginine and glucose or xylose are described here: high-performance anion-exchange chromatography coupled to integrated pulsed amperometric detection (HPAEC-IPAD) and reversed-phase ultra-high-performance liquid chromatography combined with charged aerosol detection (RP-UHPLC-CAD). Both were thoroughly validated in a lysogeny broth, a minimal medium, and a complex medium containing corn steep liquor. HPAEC-IPAD displayed an excellent specificity, accuracy, and precision for arginine, glucose, and xylose in minimal medium and lysogeny broth, whereas specificity and accuracy for arginine were somewhat lower in medium containing corn steep liquor. RP-UHPLC-CAD exhibited high accuracy and precision, and enabled successful monitoring of arginine and glucose or xylose in all media. The present study describes the first successful application of the above chromatographic methods for the determination and monitoring of L-arginine amounts during its fermentative production by a genetically modified Escherichia coli strain cultivated in various growth media.

An isocratic HPLC charged aerosol detector (CAD) method was developed, validated, and applied for the determination of individual bile acids in human gastric and duodenal aspirates. The method requires a low volume of aspirates (50–100 μl) and minimal sample pretreatment. A Hypersil BDS RP-C18 column (250 × 4.6 mm, 5 μm particle size) was equilibrated with a mobile phase composed of methanol-[ammoniun formate 20 mM, formic acid 0.5%, triethylamine 0.2% (pH 3)] 67:33 v/v. Its flow rate was 1 ml/min. The elution times for taurocholate, glycocholate, taurochenodeoxycholate, ursodeoxycholate, glycochenodeoxycholate, cholate, and glycodeoxycholate were approximately 9.9, 16.2, 18.2, 21.3, 31.6, 34.5, and 38.5 min, respectively. Calibration curves in the mobile phase were constructed in the concentration range of 0.5–500 μM. Limits of detection and quantification were in the range of 0.07–0.60 μM and 0.20–1.80 μM, respectively. This method was applied first, in gastric aspirates collected in the fasted state, in which bile acid presence is minimal and, second, in duodenal aspirates collected in the fed state, in which a large number of potentially interfering compounds exists. Intra-day relative standard deviation in fasted gastric aspirates and in fed duodenal aspirates was less than 2.2% and 6.0%, respectively.

A robust, high-throughput method using hydrophilic interaction liquid chromatography (HILIC) coupled with a charged aerosol detector (CAD) is reported as a novel approach for trisulfide quantitation in monoclonal antibodies (mAbs). The products of mAb reduction using tris (2-carboxyethyl)phosphine (TCEP) include a species (TCEP(S)) that is stoichiometrically produced from trisulfides. The TCEP reaction products are chromatographically separated, detected, and quantified by the HILIC CAD method. The method was qualified to quantify trisulfides across a range of 1–40% (mol trisulfide/mol mAb). In all tested matrix components, assay linearity and intermediate precision were established with correlation coefficients (R 2 ) > 0.99, and relative standard deviations (RSD) < 10%. A method comparability study was performed using peptide mapping LC–MS as an orthogonal measurement. For the range of 1–40% trisulfides, the analysis demonstrates that, on average, HILIC CAD reads between 0.95 and 1.10 times the value of LC–MS with 95% confidence. Applications of the HILIC CAD method include trisulfide determination in purified mAbs to be used in the production of cysteine-linked antibody-drug conjugates, and in cell culture development studies to understand sources of, and strategies for control of, trisulfides. [ABSTRACT FROM AUTHOR]