Determination of dehydroepiandrosterone in dietary supplements by reversed-phase HPLC

Purpose: To develop a reversed phase high performance liquid chromatography (HPLC) method for the determination of dehydroepiandrosterone (DHEA) in dietary supplements. Methods: A reversed-phase high performance liquid chromatography (HPLC) method was developed for the determination of DHEA in dietary supplements. An isocratic system consisting of methanol and water (70:30 v/v) was run at a flow rate of 1 mL/min on a C18 HPLC column to achieve the separation. The method was validated with regard to linearity, intra-day and inter-day precision, and limits of both detection and quantification. Results: The method achieved a retention time of 10.8 min, a resolution of 4.12, a detection limit (LOD) of 50 ng/μL, a quantification limit (LOQ) of 166.7 ng/μL and a label claim of 108.6 % with a relative standard deviation (RSD) of 0.38 % over a range of 0.0625 – 0.50 mg/mL with a correlation coefficient of 0.9997. Conclusion: The method is simple, cost effective, time-saving and reliable for determining DHEA when compared to other reported methods in literature. Thus, it will be of benefit to manufacturers of this dietary supplement to adopt the method for quantitative laboratory analysis.

Bioanalysis of aminoglycosides using high-performance liquid chromatography

Aminoglycosides are broad-spectrum antibiotics used in the treatment of gram-negative bacterial infections. Due to their nephrotoxic and ototoxic potential (narrow therapeutic index), the use of aminoglycoside for clinical indications requires monitoring. The objective of this review was to identify relevant literature reporting liquid chromatographic methods for the bioanalysis of aminoglycosides in both preclinical and clinical settings/experiments. Data on liquid chromatographic methods were collected from articles in an online academic database (PubMed, Science Direct, Scopus, and Google Scholar). All 71 articles published from 1977 to 2020 were included in the review. Reversed-phase liquid chromatography was the most used method for the bioanalysis of aminoglycosides. Fluorescence or ultraviolet detection methods were mostly used from 1977 to 2002 (51 articles), while mass spectrometry was predominantly used as a detector from 2003 to 2020 (15 articles). Sixty-seven articles reported calibration ranges, which varied significantly for the various drugs assayed: some in the range of 0.1-0.5 ng/mL and others 1250-200000 ng/mL. Also, 61 articles reported R2 values (0.964-1.0) for almost all analytes under consideration. Sixty-three articles reported percent recoveries mostly between 61.0 % to 114.0 %, with only two articles reporting recoveries of 4.9 % and 36 %. Out of the 71 reviewed articles, 56 reported intermediate precision values ranging between 0.331 % to 19.76 %, which is within the acceptable limit of 20 %. This review will serve as a guide for research and/or routine clinical monitoring of aminoglycosides in biological matrices.

Simultaneous Determination of Caffeine and Paracetamol in Commercial Formulations Using Greener Normal-Phase and Reversed-Phase HPTLC Methods: A Contrast of Validation Parameters

There has been no assessment of the greenness of the described analytical techniques for the simultaneous determination (SMD) of caffeine and paracetamol. As a result, in comparison to the greener normal-phase high-performance thin-layer chromatography (HPTLC) technique, this research was conducted to develop a rapid, sensitive, and greener reversed-phase HPTLC approach for the SMD of caffeine and paracetamol in commercial formulations. The greenness of both techniques was calculated using the AGREE method. For the SMD of caffeine and paracetamol, the greener normal-phase and reversed-phase HPTLC methods were linear in the 50–500 ng/band and 25–800 ng/band ranges, respectively. For the SMD of caffeine and paracetamol, the greener reversed-phase HPTLC approach was more sensitive, accurate, precise, and robust than the greener normal-phase HPTLC technique. For the SMD of caffeine paracetamol in commercial PANEXT and SAFEXT tablets, the greener reversed-phase HPTLC technique was superior to the greener normal-phase HPTLC approach. The AGREE scores for the greener normal-phase and reversed-phase HPTLC approaches were estimated as 0.81 and 0.83, respectively, indicated excellent greenness profiles for both analytical approaches. The greener reversed-phase HPTLC approach is judged superior to the greener normal-phase HPTLC approach based on numerous validation parameters and pharmaceutical assays.

Identification and Distribution of Sterols, Bile Acids, and Acylcarnitines by LC–MS/MS in Humans, Mice, and Pigs—A Qualitative Analysis

Sterols, bile acids, and acylcarnitines are key players in human metabolism. Precise annotations of these metabolites with mass spectrometry analytics are challenging because of the presence of several isomers and stereoisomers, variability in ionization, and their relatively low concentrations in biological samples. Herein, we present a sensitive and simple qualitative LC–MS/MS (liquid chromatography with tandem mass spectrometry) method by utilizing a set of pure chemical standards to facilitate the identification and distribution of sterols, bile acids, and acylcarnitines in biological samples including human stool and plasma; mouse ileum, cecum, jejunum content, duodenum content, and liver; and pig bile, proximal colon, cecum, heart, stool, and liver. With this method, we detected 24 sterol, 32 bile acid, and 27 acylcarnitine standards in one analysis that were separated within 13 min by reversed-phase chromatography. Further, we observed different sterol, bile acid, and acylcarnitine profiles for the different biological samples across the different species. The simultaneous detection and annotation of sterols, bile acids, and acylcarnitines from reference standards and biological samples with high precision represents a valuable tool for screening these metabolites in routine scientific research.

HPLC determination of Escitalopram in tablet dosage forms

Purpose: A simple, specific, precise, and accurate reversed phase liquid chromatographic (RP-LC) method has been developed for the determination of Escitalopram in tablet dosage form. Methods: The chromatographic separation was achieved on a LiChrosorb C18, 250 mm x 4.6 mm, 5 μm column at a detector wavelength of 270 nm and a flow rate of 1.0 ml/min. The mobile phase was composed of methanol, acetonitrile (70:30 v/v). The retention time of Escitalopram was 5.49 min. The method was validated for the parameters like specificity, linearity, precision, accuracy, limit of quantitation and limit of detection. Results: The method was found to be specific as no other peaks of impurities and excipients were observed. The square of correlation coefficient (R2) was 0.9999 while relative standard deviations were found to be <2.0%. Conclusion: The proposed RP-LC method can be applied for the routine analysis of commercially available formulations of Escitalopram.

Kajian Kadar Akrilamida dalam Kopi Arabika dengan Variasi Suhu Penyangraian

Acrylamide levels in Arabica coffee at various roasting temperatures have been determined. Coffee beans are roasted at 160°C, 180°C, and 210°C for 8 minutes. Analysis was carried out using High-Performance Liquid Chromatography (HPLC) with C-18 reversed-phase, mobile phase using methanol and 0.1% phosphoric acid solution (5:95), flow rate 1 mL/min, UV-Vis detector 198 nm wavelength. Acrylamide levels in Arabica coffee are 160°C of 14.665 ppm, 180°C of 15.973 ppm, and 210°C of 18.501 ppm. Based on the results of the acrylamide content in Arabica coffee, the higher the roasting temperature, the greater the acrylamide content. ANOVA test regarding the normality test sig value of 0.637, 0.463, and 0.637 normally distributed. Based on the homogeneity test, it was found that the variation between groups was the same or homogeneous. The results of the ANOVA test stated that there were differences in the acrylamide levels of Arabica coffee in the roasting temperature difference group and the results of the post hoc Bonferroni test found that the average differences in the roasting temperature of Arabica coffee were significantly different 160°C-180°C and 160°C-210°C.

Identification of benzydamine and its metabolit in the presence of certain anti-inflammatory non-steroidal drugs

The aim of the work. Currently, a large number of cases of non-medical use of benzydamine hydrochloride have been described. The identification of benzydamine and its metabolite, benzydamine N-oxide, in the presence of some non-steroidal anti-inflammatory drugs, has been insufficiently studied. Therefore, the development of a method for its identification in biological material is an urgent task. Materials and methods. The subjects of the study were benzydamine hydrochloride and its metabolite, as well as some non-steroidal anti-inflammatory drugs, which are its analogues in terms of pharmacological action. The studies were carried out by methods of thin layer chromatography and high-performance liquid chromatography. Results. At the first stage a screening method for benzydamine identification was studied using the extraction in acidic and basic conditions. It was shown that benzydamine can be isolated in both medias with subsequent development with a solution of iodoplatinate and Dragendorff's reagent according to Munier or with Mandelin reagent respectively. The mobile phase was selected and respective hRf for the target molecule were defined. After a preliminary identification of benzydamine a reference method for the final confirmation of the drug that had led to poisoning was proposed. A robust, specific and accurate reversed phase HPLC method was chosen. It was shown that benzydamine exists in biological material mainly in a form of metabolite – benzydamine N-oxide. The selected method was able to separate and determine key analytes in biological samples after a preparative isolation by TLC method. The comparison with UV spectra of the reference standard of benzydamine hydrochloride was proposed to avoid false positive conclusion of drug identification. Conclusions. Proposed methodology can be applied for routine identification of benzydamine poisoning in toxicological laboratories