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Abstract

This paper is aimed at developing a gradient elution reversed-phase high-performance liquid chromatography (RP-HPLC) method for the separation of a complex mixture composed of ivabradine and its eleven impurities, in a reasonable timeframe. In order to obtain a robust and reliable HPLC method for separation of this mixture, Analytical Quality by Design (AQbD) was applied. This approach demonstrated to be useful in development of a long lasting life cycle methods. Four chromatographic variables were defined as key method parameters (KMPs) and optimized towards the analytical target profile (ATP). Designated KMPs were initial and final amount of acetonitrile in the mobile phase, pH value of the aqueous phase and gradient time, while resolutions of critical peak pairs were denoted as critical method attributes (CMAs). Relationships between KMPs and CMAs were obtained with the aid of Design of Experiments (DoEs) methodology among which Box-Behnken design (BBD) was employed to gain valid mathematical models. Obtained mathematical equations were used to construct the Design Space (DS) and select reliable optimal separation conditions. They included 11% (v/v) and 34% (v/v) of initial and final amount of acetonitrile, respectively, as well as 45 min of gradient elution time and 20 mM ammonium acetate as aqueous mobile phase with pH set to 7.35. The possibility to separate the diastereoisomers of impurity X was also evaluated. It was demonstrated that this separation could not be achieved in gradient elution mode within the defined variable domains and in a reasonable time span. The developed method was validated according to ICH Q2 (R1) guideline and met all the required criteria.

Open access

Abstract

A rapid, sensitive and convenient method based on ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was developed and validated for the simultaneous quantification of calycosin-7-O-β-d-glucoside (CCSG), ononin, calycosin, (6aR,11aR)-9,10-dimethoxypterocarpan-3-O-β-d-glucopyanoside (DPPG), and 7,2′-dihydroxy-3′,4′-dimethoxyisoflavan-7-O-β-d-glucopyanoside (DIFG) in rat plasma after oral administration of the methanol extraction from Radix Astragali. Theophylline played the role of internal standard (IS). Preparation of plasma samples by liquid-liquid extraction method with ethyl acetate after precipitation of protein with methanol. The analytes were detected with a triple quadrupole tandem mass spectrometery (MS) in multiple reaction monitoring (MRM) mode and a positive ion electrospray ionization (ESI). The method was validated with the concentration ranges of 1.96–62.69 ng/mL for CCSG, 1.70–54.5 ng/mL for ononin, 1.85–59.06 ng/mL for calycosin, 2.14–137.24 ng/mL for DPPG and1.96–125.25 ng/mL for DIFG, respectively. The method had the lower limit of quantification (LLOQ) with 0.49, 0.21, 0.92, 1.07, and 0.98 ng/mL for CCSG, ononin, calycosin, DPPG and DIFG respectively, and the precision less than 10%. The RSD of the accuracy was in the range of −4.35–8.91%. The results may be helpful to provide more accurate references to clinical application of this herb.

Open access

Abstract

A rapid and simple UPLC-MS/MS method was developed to determine toddalolactone in mouse blood and applied to measure the pharmacokinetics of toddalolactone in mice. Blood samples were first preprocessed by ethyl acetate liquid-liquid extraction. Oxypeucedanin hydrate (internal standard, IS) and toddalolactone were gradient eluted from a UPLC BEH C18 column using a mobile phase consisting of acetonitrile and water (0.1% formic acid). Using electrospray ionization (ESI) as the ionization source, multiple reaction monitoring was used to detect the precursor and product ions of m/z 309.2 and 205.2, respectively, for toddalolactone and of m/z 305.1 and 203.0 for IS, respectively, for quantitative detection. A calibration curve was run over the concentration range of 5–4,000 ng/mL (r > 0.995). The matrix effects ranged from 93.5 to 98.4%, and the recovery was higher than 77.3%. The precision was less than 13%, and the accuracy ranged from 90.9 to 108.4%. The developed UPLC-MS/MS method was successfully used for measuring the pharmacokinetics of toddalolactone in mice after oral (20 mg/kg) and intravenous administration (5 mg/kg), and the absolute bioavailability of toddalolactone was 22.4%.

Open access

Abstract

Bao-Yuan Decoction (BYD), a widely used traditional Chinese medicine formula, is worth developing into modern dosage forms. To assess the quality of traditional decoction, the commonly used ultra-performance liquid chromatography coupled with diode array and evaporative light scattering detection (UPLC-DAD/ELSD) method was initially applied to develop the analytical methods for the qualitative fingerprints and simultaneous quantitation of multiple marker compounds in BYD. Based on 16 batches of BYD prepared from multiple batches of qualified crude herbs combined randomly, the characteristic fingerprints were generated, with 41 and 19 common peaks detected by DAD and ELSD, respectively. Furthermore, ginsenosides Re, Rg1 and Rb1, calycosin-7-glucoside, calycosin, liquiritin, isoliquiritin apioside, isoliquiritin, glycyrrhizic acid and cinnamic acid were qualified as marker compounds to represent the herbs composing the formula. The characteristic fingerprints and the content ranges of multiple batches of the decoction were obtained, thus providing guidance for the quality control of modern dosage forms. The combination of these qualitative and quantitative methods will be an effective operational measure by which to evaluate and control the quality of BYD from traditional decoction to modern dosage forms.

Open access
Acta Chromatographica
Authors: Dżastin Zimny, Michał Patrzałek, Teresa Kowalska, Mieczysław Sajewicz, Kinga Surmiak-Stalmach, and Grażyna Wilczek

Abstract

This is the first study on composition of fatty acids in hunting web of Steatoda grossa (Theridiidae) spiders and one of only four similar studies ever made. Its main contribution is a discovery that fatty acids not only cover an outside of the web fibers, but they are even more abundantly represented in the fibers’ inner structure. Although little attention has been so far attributed to the contents of fatty acids in spider silks, one has to remember that their biocompatibility combined with an extraordinary tensile strength make them a worth investigating template for material bioengineering studies.

Open access

Abstract

In this study, a new microextraction method based on hydrophobic deep eutectic solvents was developed for the extraction and preconcentration of organophosphorus pesticides from beverage samples. The hydrophobic deep eutectic solvents were synthesized from choline chloride and 4-chlorophenol. Main experimental parameters of the microextraction method were investigated to improve the extraction efficiency. The proposed method achieved a satisfactory linear range between 50 and 2,000 μg L−1 with coefficient of determination greater than 0.9939. The extraction recoveries and enrichment factor of five organophosphorus pesticides at three added levels ranged from 71.68 to 113.18% and 71.43–111.11 were obtained with the acceptable relative standard deviation ranged from 1.37 to 11.92%. Limits of detection and quantification were found to be 0.05–0.3 μg L−1 and 0.17–1 μg L−1, respectively. Finally, the methods were successfully applied for the determination of five organophosphorus pesticide in orange juice and green tea.

Open access

Abstract

A new and rapid hydrophilic interaction liquid chromatographic method has been developed for the quantitative analysis of amlodipine besylate and its specific impurities (D, E, and F). For development of this method, a systematic approach which includes Design of Experiments methodology was applied. For the method optimization, Box–Behnken design and specific way Derringer's desirability function were applied. They provided identification of the optimal chromatographic conditions on the basis of obtained mathematical models and graphical procedures (three D graphs). The optimal chromatographic conditions were the analytical column ZORBAX NH2 (250 × 4.6 mm, 5 µm particle size); mobile phase consisted of acetonitrile-water phase (50 mM ammonium acetate, pH adjusted to 4.0 with glacial acetic acid) (90.5:9.5 v/v); column temperature 30 °C, mobile phase flow rate 1 mL min−1, wavelength of detection 230 nm. As other validation parameters were also found to be suitable, the possibility to apply the proposed method for the determination of amlodipine besylate and its impurities in any laboratory under different circumstances has been proven.

Open access

Abstract

Pharmaceuticals which are widely used in aquatic can easily migrate into the environment and aquatic animals, and can increase the risk of drug resistance and allergic symptoms if consumed by humans. In order to achieve high-throughput analysis of pharmaceuticals with different physical and chemical properties from complex matrices, we developed a new method for various types pharmaceuticals in fish and shrimp tissue. Series solid-phase extraction (s-SPE) with different adsorbents was selected for extracting and purifying analytes with different paddings. s-SPE were combined with ultra performance liquid chromatography triple quadruple tandem mass spectrometry (UPLC-MS/MS) for the detection of 30 pharmaceuticals antibiotics in fish samples. This method was stabilized and reliable to determinate the pharmaceuticals in fish and shrimp samples. As the method combined multiple Chinese national standards method, it could be easily treat the multi-pharmaceuticals from the fish and shrimp samples once time. It provided for both quantitative and qualitative methods and they could be applied to single- or multi-residue methods.

Open access

Abstract

In this study, a simple, fully validated and rapid reversed-phase HPLC with photodiode array detector method was developed for the simultaneous determination of 11 selected phenolic antioxidants over 33 min in personal care and food samples containing extracts of green apple, pomegranate (Ponica granatum) and argan oil (Argania spinosa). The method was performed using NUCLEODUR C18 column 5 µm particle size and 12.5 cm length. The HPLC mobile phase was prepared as follows, solution A: 1% aqueous acetic acid and solution B: Acetonitrile. The method was gradient at flow rate 1.0 mL/min with a simple mobile phase, minimal sample preparation, and diminished organic solvent usage (3% acetonitrile for almost 90% of the run time). The detection was carried out at 278 nm. The method presented good precision and accuracy with RSD% values ranged between 0.33 and 1.94% and wide linear range. The developed method was successfully applied on 67 personal care and food products present in Egyptian market and can be used for routine screening in laboratory for the regular quality control of the antioxidant content for products containing the mentioned extracts.

Open access

Abstract

Schizonepeta tenuifolia Briq. (ST) has been used as an aromatic exterior-releasing medicine in clinical practice for thousands of years in China. Previous researches have revealed both volatile oil (STVO) and aqueous extract (STAE) from ST showed significant pharmacological activities, such as anti-virus, anti-inflammation, anti-oxidation, and immunoregulation. However, the influence between each other was still unknown. The purpose of this study was to compare the pharmacokinetic profiles of three main flavonoids (luteoloside, apigetrin, and hesperidin) in STAE to illustrate the influence of STVO. A liquid chromatography-tandem mass spectrometry (HPLC-MS) method was established to quantitatively analyze the three absorbed ingredients in the plasma of healthy rats. Biological samples were analyzed on an Agilent Eclipse Plus C18 column (3.0 mm × 150 mm, 3.5 μm) with gradient mobile phase (containing 0.2% formic acid and acetonitrile) at a flow rate of 0.8 mL/min. All the analytes and quercitrin (IS) were investigated with an electrospray ionization source (ESI) using multiple-reaction monitoring (MRM) in negative ionization mode. In addition, this quantitative method showed good linearities (r ≥ 0.9995) and the lower limits of quantification were 0.590–1.19 ng/mL. The intra- and inter-day precisions ranged 3.47–10.45% and 4.29–11.28% for the three analytes. The mean extraction recoveries were in the range of 77.41–109.79% and the average matrix effects were within 83.41–112.67%. The validated method has been fully applied to compare the pharmacokinetic parameters of the three flavonoid glycosides in rat plasma after oral administration of STAE and STAE+STVO. In comparison of luteoloside, apigetrin, and hesperidin in STAE group, it was found that different degree of increasing existed for the time to reach the maximum concentration (T max), elimination half-life time (T 1/2), the area under the concentration curves (AUC0→t and AUC0→∞) and the maximum concentrations (C max) in STAE+STVO group. As can be seen from above results, STVO could improve the absorption and bioavailability of the three analytes. These findings would provide some active and strong basis of safe clinical application for ST and further exploitation for STVO from the perspective of drug–drug interaction.

Open access