Stability Indicating RP-HPLC Method Development and Validation for Simultaneous Quantification of 15 Organic Impurities of Olmesartan Medoxomil, Amlodipine and Hydrochlorothiazide in Combined Dosage Form The authors would like to call the reader’s attention to the following change in the corresponding authorship to Priti J. Mehta and Pritesh R. Desai’s affiliation.

Nimir O. Elbashir, Mahmoud M. El-Halwagi, Ioannis G. Economou, Kenneth R. Hall (Eds): Natural Gas Processing from Midstream to Downstream

Correction to: Critical Comparison of Liquid Chromatography Coupled to Mass Spectrometry and Three Different Ion Mobility Spectrometry Systems on Their Separation Capability for Small Isomeric Compounds Unfortunately a second footnote (Published in the topical collection 24th International Symposium on Separation Sciences …) was added to the original submission.

Dieter Sicker, Klaus-Peter Zeller, Hans-Ullrich Siehl, Stefan Berger: Natural Products. Isolation, Structure, Elucidation, History

Correction to: Determination of Semicarbazide in Foodstuffs by HPLC with Fluorescence Detection Using 2-Formylphenylboronic Acid as Derivatization Reagent The authors would like to call the reader’s attention to the following correction of the erroneous chemical structures of 2-formylphenylboronic acid (FPBA) and FPBA-SEM derivative in the Graphical Abstract and in Fig. 1.

Congress, Conferences, and Workshops

Development and Validation of a CE Method for the Determination of Tetracyclines with Capacitively Coupled Contactless Conductivity Detection Abstract In this study, a simple and robust capillary electrophoresis method with capacitively coupled contactless conductivity detection (C4D) is developed for the determination of the tetracycline antibiotics (1) tetracycline, (2) chlortetracycline and (3) oxytetracycline. An uncoated, fused silica capillary (60.2 cm long, 75 µm i.d.) and a solution of 50 mM tris(hydroxymethyl) aminomethane, 50 mM l-histidine and 5 mM methyl-β-cyclodextrin, without pH adjustment (pH 8.76), was used as background electrolyte. Electrophoresis at + 25 kV showed a rapid analysis with sufficient resolution among the three antibiotics in the order of tetracycline, chlortetracycline and oxytetracycline. Successive inter-injection rinsing (20 psi) of the capillary ensured intra- and inter-day repeatability (0.9–2.2% RSD and 2.0–4.5% RSD, respectively, for relative peak areas). The method showed satisfactory performance in terms of selectivity, accuracy (99.3–101.4%) and linearity (R2 = 0.999). Finally, the method was applied to commercial samples of tetracycline, oxytetracycline and chlortetracycline. This method can be applied for rapid quality control in developing countries in particular, and across the globe in general.

The Limited Contribution of the Analyte Partition to the Water-Rich Layer in Immobilized Artificial Membrane Chromatography with an Acetonitrile-Rich Binary Mobile Phase Abstract Drug-induced phospholipidosis, a side effect of drugs, is associated with drug–membrane binding. Hydrophobic interactions of the drug with the membrane and polar interactions of the drug with the membrane are involved. For risk predictions, membrane binding studies often give false results for strongly hydrophobic compounds and basic hydrophilic compounds because the effects of the hydrophobic interactions overshadow the effects of the polar interactions. Therefore, separate assessments of hydrophobic partitioning and polar interactions are needed. However, a screening method focusing on the polar interactions between drugs and membranes has not yet been reported. In the present study, the retention behavior of an immobilized artificial membrane (IAM) column using a binary mobile phase with a high acetonitrile content was studied to clarify the contribution of the analyte partition to the water-rich layer on the surface of the packed material, which may interfere with the assessment of the polar interactions with the membrane. For acetonitrile contents greater than 50%, the retention factor of propranolol increased as a result of the hydrophilic interactions. The Van’t Hoff plot suggested that the adsorptive retention of the analyte became dominant with high acetonitrile content in the mobile phase, in contrast to the hydrophobic partitioning that occurred for low acetonitrile content. Hydrophilic neutral compounds (e.g., thiourea and mesityl oxide) were not retained. The addition of salts to the mobile phase decreased the propranolol retention. Even with the addition of a kosmotropic salt, the decreased retention indicated that hydrophilic partitioning to the water-enriched layer was unlikely to be the major mechanism. In addition to ionic interactions, other polar interactions were presumed to be involved. The relationships between the retention factor and the log P or pKa values also supported this conclusion. The results of this study suggest that there is potential for IAM chromatography to be used as a tool to estimate the contribution of the polar interactions in overall drug–membrane interactions, which can aid in predicting the risk of phospholipidosis.

Detection of Illegal Abortion-Induced Drugs Using Rapid and Simultaneous Method for the Determination of Abortion-Induced Compounds by LC–MS/MS Abstract With an increase in the number of individuals opting for illegal abortion, the use of counterfeit abortion medicines is increasing throughout the black market. In the present study, a rapid and simultaneous liquid chromatography–tandem mass spectrometry method for detecting abortion-inducing drugs in counterfeit medicines was developed. The parameters used for validating the method using tablet-, powder- and capsule-type matrix-blank samples were limit of detection (0.10–5.00 ng/mL), limit of quantitation (0.31–15.00 ng/mL), linearity (r2 > 0.998), recovery of spiked matrix-blank samples (83.1–114.5%), intraday and interday accuracy (86.4–113.5%) and precision (≤ 9.7% RSD) and stability (≤ 13.3% RSD). Seized tablet-type drugs, advertised for their abortion-inducing activity, were analysed using an established method and were observed to be adulterated with mifepristone and misoprostol in a concentration of 0.02–293.80 mg/g, which can pose a risk to public health. This study demonstrates the successful application of a fast and reliable screening method for detecting illegal abortion-inducing drugs.

A Novel Method of Extracting Total Flavonoids from Scutellaria barbata Abstract This study aims to compare and determine the optimum extraction and separation process of the total flavonoids from Scutellaria barbata. The total flavonoids from S. barbata were extracted with an l-arginine solution, methanol, ethyl acetate, and n-butanol. The activities and toxicity of different extracts on HepG2 and L-O2 cells were measured by MTT assay. The TLC method revealed in the sample chromatograms that the l-arginine extract showed the same patches as the chromatogram of the standard substance. The TLC spots were clear and centralized, and the Rf values of the extract of the l-arginine solution were identical with those of the Rutin and Naringin standard preparations. The number of HPLC chromatographic peaks of the l-arginine solution extract was more than those of the other extracts. In vitro experiments indicated that at the concentration of 400 μg mL−1, S. barbata extracted by l-arginine solution has a significant inhibitory effect on human hepatic carcinoma HepG2 cells as well as a lower toxic effect on L-O2 cells. In conclusion, l-arginine can maintain the maximum stability of flavonoids from S. barbata. In addition, the S. barbatal-arginine extracts possess favourable anti-tumour effects. Therefore, the extraction method in the present study using l-arginine can improve the clinical use and industrial production of S. barbata preparations, and also can be a reference method for the extraction of flavonoids from other plants.