Silica Gel Plates Research Articles

Bioactivity profiles of six baobab fruit pulp powders via planar chromatography hyphenated with effect-directed analysis

Baobab (Adansonia digitata) fruit pulp has a high nutrient content and has been traditionally used for medicinal purposes (e.g., as an anti-inflammatory and antioxidant agent) that may help protect against chronic diseases. Six different baobab fruit pulp powders were investigated using three different extractants and analyzed by high-performance thin-layer chromatography (HPTLC) hyphenated with antibacterial bioassays and enzyme inhibition assays. The developed non-target effect-directed screening was performed after extraction with pentyl acetate – ethanol 1:1 (V/V) on the HPTLC plate silica gel 60 using toluene – ethyl acetate – methanol 6:3:1 (V/V/V) as mobile phase system and derivatization via the anisaldehyde sulfuric acid reagent for detection. The physico-chemical profiles of the six baobab fruit pulp powder extracts were comparable, although the intensity of some zones was moderately different. The following effect-directed profiling via tyrosinase, α-glucosidase, and acetylcholinesterase inhibition assays as well as antibacterial Aliivibrio fischeri and Bacillus subtilis bioassays revealed one prominent multipotent bioactive compound zone in common, more or less active in all five studied (bio)assays. Via the recording of high-resolution mass spectra, this compound zone was tentatively assigned to coeluting saturated (palmitic acid 16:0 and stearic acid 18:0), monounsaturated (oleic acid 18:1), and polyunsaturated (linoleic acid 18:2 and linolenic acid 18:3) fatty acids. This finding was confirmed by other studies, which already proved individual activities of fatty acids. The first (bio)activity profiling of baobab fruit pulp powders via HPTLC-effect-directed analysis revealed that the baobab fruit could be considered as a functional food, however, further research is needed to study the impact on health and the influences on the bioactivity arising from different climates, years and soils or regions.

Comparative analysis of analytical method development and its validation for the simultaneous estimation of Bilastine and Montelukast Sodium in bulk and its tablet formulation by planar chromatography

The development and validation of analytical methods are crucial in guaranteeing the precision, dependability, and excellence of pharmaceutical analysis. This research investigates the field of pharmaceutical chemistry by doing a comparative examination of analytical techniques for the simultaneous determination of Bilastine and Montelukast Sodium in both bulk and tablet forms. The selected method for this analysis is planar chromatography. The simplicity, specificity, precision, and accuracy of a high-performance liquid chromatography (HPTLC) approach were investigated for their use in the simultaneous estimation of the antihistaminic combination medication Bilastine and Montelukast Sodium in bulk and its pharmaceutical dose for the treatment of allergic rhinitis. Densitometric readings were taken at 254 nm after separating substances using ethyl acetate, toluene, methanol, and ammonia (7:0.5:1.5:0.5v/v/v/v) as mobile phase and precoated aluminium silica gel plates (60F254) as stationary phase. Bilastine and montelukast Sodium have Rf values 0.2 (Bilastine) & 0.4 (Montelukast Sodium), which is considered an acceptable resolution. The International Conference on Harmonization's (ICH) requirements validated the processes for accuracy, linearity, precision, robustness, and system adaptability. Bilastine and Montelukast Sodium concentrations were determined without any disruption from the excipients. Both Bilastine and Montelukast Sodium were effectively quantified using the suggested method, which bodes well for its utility in enhancing quality assurance.

QUALITATIVE ANALYSIS OF DRUG SUBSTANCES IN RHEUMATIC JAMU SAMPLES USING THIN LAYER CHROMATOGRAPHY

Since ancient times, jamu have been used to treat various diseases. Recently, the number of jamu has increasing and this has led several manufacturers to commit fraud. They added drug substances (DS) into jamu for gaining the effect of jamu so that can raise the sales of jamu in market . The addition of DS into herbal medicine is a violation of the regulation issued by The Ministry of Health. Such practices can cause side effects that are very dangerous for health. The purpose of this research is to analyze the presence of DS in jamu samples that are frequently consumed and circulated in Kranggan, Temanggung and Magelang city. Thin-Layer Chromatography (TLC) was employed to detect the presence of prednisone, paracetamol, and mefenamic acid. The working principle of the separation of compounds with TLC is to separate samples based on the partition difference between samples and the solvent used. In this case, the stationary phase used is the silica gel plate GF254 with the mobile phase for prednisone using ethyl acetate:chloroform (4:1), mefenamic acid using chloroform:methanol (9:1),and paracetamol using chloroform:ethanol (8:1). As a result of qualitative analysis, jamu samples in those areas do not contain any drug substances that were suspected to be present. Keywords: jamu, prednisone, paracetamol, mefenamic acid

Screening bisphenols in complex samples via a planar Arxula adeninivorans bioluminescence bioassay

The Arxula yeast bisphenol screen (A-YBS) utilizes the bioluminescent Arxula adeninivorans yeast–based reporter cells for tailored analysis of bisphenols, one of the major endocrine-disrupting compound groups. For the first time, this bioreporter has been applied on the high-performance thin-layer chromatography (HPTLC) adsorbent surface to develop a respective planar bioluminescence bioassay (pA-YBS). The goal was to combine the advantages of HPTLC with a more selective bioassay detection for bisphenols. The performance of this pA-YBS bioluminescence bioassay was demonstrated by calculating the half-maximal effective concentration (EC50) of bisphenols compared to references. The EC50 ranged from 267 pg/band for bisphenol Z and 322 pg/band for bisphenol A (BPA) to > 1 ng/band for other bisphenols (BPC, BPE, BPF, and BPS) and references (17β-estradiol and 17α-ethinylestradiol). The EC50 value of BPA was three times more sensitive in signal detection than that of 17β-estradiol. The visual or videodensitometric limit of detection of BPA was about 200 pg/zone. The higher signal intensity and sensitivity for BPA confirmed the tailored bioassay selectivity compared to the existing estrogen screen bioassay. It worked on different types of HPTLC silica gel plates. This HPTLC–UV/Vis/FLD–pA-YBS bioluminescence bioassay method was used to analyze complex mixtures such as six tin can migrates, five thermal papers, and eleven botanicals. The detected estrogenic compound zones in the tin can migrates were successfully verified via the duplex planar yeast antagonist estrogen screen (pYAES) bioassay. The two bisphenols A and S were identified in one out of five thermal papers and confirmed with high-resolution mass spectrometry. No bisphenols were detected in the botanicals investigated via the pA-YBS bioluminescence bioassay. However, the botanicals proved to contain phytoestrogens as detected via the pYAES bioassay, which confirmed the tailored bioassay selectivity. This HPTLC–UV/Vis/FLD–pA-YBS bioluminescence bioassay is suited for cost-efficient analysis of BPA in complex samples, with no need for sterile conditions due to the fast workflow.

Synthesis and Characterization of 1-(1-naphthyl)-5-phenyl-2,4-pentadien-1-one from trans-cinnamaldehyde and 1-acetonaphthone

Chalcone analogues (1-(1-naphthyl)-5-phenyl-2,4-pentadiene-1-one) have been synthesized through an aldol condensation reaction between cinnamaldehyde and 1-acetylnaphthalene. The method used in this study is the stirrer method, with the reaction conducted at room temperature for 24 hours using a NaOH catalyst in H2O/ethanol (50%, v/v). The purity of the product was analyzed using thin-layer chromatography on silica gel plates with n-hexane: ethyl acetate (9:1) employed as the solvent. The resulting product obtained was 0.88 g with a yield of 61.97%. Structure Analysis and elucidation of the synthesized compounds were performed by measuring the vibrations of the functional groups using FTIR, LCMSMS analysis, and determining the 1H and 13C atoms by HNMR and CNMR analysis. The FTIR, LCMSMS, 1H, and 13C NMR analysis identified that the synthesized product as chalcone analogues, specifically 1-(1-naphthyl)-5-phenyl-2,4-pentadiene-1-one.

Dual-mode “turn-on” fluorescence and colorimetric probe toward cyanide based on ESIPT and its bioimaging applications

It's important to pay great attention to the detection of CN− due to its high toxicity. Based on ESIPT characteristics, we design, synthesize and characterize the colorimetric and fluorescence “turn-on” probe AHAM to recognize CN−, which has the large Stokes shift (228 nm), exhibits high sensitivity and excellent selectivity. The limit detection of the probe AHAM for CN− was 1.94 × 10−8 M, which was much lower than the standard set by WHO and many previously reported probes. The recognition mechanism between AHAM and CN− was investigated by spectroscopic analysis, 1H NMR titration and mass spectrometry. To our surprise, AHAM could not only identify CN− reversibly, but also recognize CN− accurately in test paper and silica gel plate applications. Furthermore, AHAM was successfully used for fluorescence imaging in C. elegans and mice. It provides the new easy, fast and accurate method to detect CN−.

Green TLC-Densitometric Method for Simultaneous Determination of Antazoline and Tetryzoline: Application to Pharmaceutical Formulation and Rabbit Aqueous Humor.

Abstract Ophthalmic pharmaceutical preparation containing antazoline (ANT) and tetryzoline (TET) is prescribed widely as an over the counter medication for allergic conjunctivitis treatment. Development of a selective, simple and environmentally friendly thin-layer chromatographic method established to determine both ANT and TET in their pure forms, pharmaceutical formulation and spiked aqueous humor samples. By using silica gel plates and means of a developing system consists of ethyl acetate:ethanol (5:5, by volume), the studied drugs separation was achieved, and scanning was carried out at 220.0 nm for the separated bands with a 0.2–18.0 μg/band concentration range for each of ANT and TET. Standard addition technique application was carried out to determine the proposed method validity. Statistical comparison was made between the proposed method and the official methods ANT and TET showing no significant difference concerning accuracy and precision. Furthermore, greenness profile assessment was accomplished by means of four metric tools, namely, analytical greenness, green analytical procedure index, analytical eco-scale and national environmental method index. Highlights

Implementation of green chemistry to develop HPLC/UV and HPTLC methods for the quality control of Fluconazole in presence of two official impurities in drug substance and pharmaceutical formulations

Two eco-friendly chromatographic methods were developed for analysis of Fluconazole (FLU) in presence of its official impurities B and C in drug substance and pharmaceutical formulations. For the HPTLC- densitometry, the separation was achieved using silica gel plates and mobile system consisting of ethyl acetate: water: acetic acid (8: 1: 1 v/v/v). The HPLC/UV was conducted on column C18 and a mixture of (water: ethanol) in gradient elution at flow rate 1.5 mL/min. The developed methods were validated according to ICH guidelines and they were able to determine FLU without interference from its two structurally related impurities with an accepted resolution and at low concentration level. The linearity was achieved over the range 50–500 μg/spot for HPTLC and 1-500 μg/mL for HPLC/UV. The LOD and LOQ values were 41.3 and 50 μg/spot for HPTLC and 0.052 and 0.15 μg/mL for HPLC/UV, respectively. The results were statistically compared to those obtained by reported methods showing no significant difference in terms of accuracy and precision. The green character of the developed methods was assessed and compared with reported methods using four different tools; NEMI, analytical eco-scale, GAPI and AGREE. The developed methods were found to be greener than the reported methods.

Simultaneous green TLC determination of nirmatrelvir and ritonavir in the pharmaceutical dosage form and spiked human plasma

Quantitative analysis of pharmaceutical compounds up to Nano gram levels is highly recommended to introduce feasible and sensitive tool for determination of the compounds in the pharmaceutical and biological samples. Nirmatrelvir plus ritonavir was recently approved in the US, the UK and Europe as a new co-packaged dosage form for the treatment of COVID-19. The objective of this work was to develop a more sensitive TLC method based on using β-cyclodextrin as a chiral selector additive in the mobile phase for simultaneous determination of nirmatrelvir and ritonavir in pure form, pharmaceutical formulation and spiked human plasma. The analysis procedures were developed using TLC aluminum silica gel plates and methanol–water- 2% urea solution of β-cyclodextrin (40:10:.5, by volume) as a mobile phase with UV detection at 215 nm. The developed method was successfully applied over a linearity range of 10–50 ng/band for both nirmatrelvir and ritonavir. The method was validated for limits of detection and quantitation, accuracy, precision, specificity, system suitability, and robustness. Furthermore, the eco-friendliness of the proposed method was assessed using the analytical eco-scale and the green analytical procedure index. The described method exhibited compliance with green analytical chemistry principles based on common green metric values.

HPTLC-Bioluminescent Bioautography Screening of Herbal Teas for Adulteration with Hypolipidemic Drugs.

Teas based on nutraceutical herbs are an effective tool against hyperlipidemia. However, the adulteration with chemical drugs is frequently detected. By coupling bioluminescent bioautography with high performance thin-layer chromatography (HPTLC), we developed a facile method suitable for screening hypolipidemic drugs (ciprofibrate and bezafibrate) adulteration in five different herbal teas (lotus leaf, Apocynum, Ginkgo biloba, Gynostemia and chrysanthemum). First, the sensitivity of a bioluminescent bacteria to the analyte was evaluated on different HPTLC layer materials, revealing that the best performance was achieved on the silica gel layer. On this basis, sample extracts were separated on silica gel plates via a standardized HPTLC procedure, forming a selective detection window for the targeted compound. Then, the separation results were rapidly visualized by the bioluminescence inhibition of bacteria cells within 6 min after dipping. The observed inhibition displayed an acceptable limit of detection (<20 ng/zone or 2 mg/kg) and linearity (R2 ≥ 0.9279) within a wide concentration range (50-1000 ng/zone). Furthermore, the optimized method was performed with artificially adulterated samples and the recovery rates were determined to be within the range of 71% to 91%, bracing its practical reliability. Showing superiorly high simplicity, throughput and specificity, this work demonstrated that the analytical method jointly based on HPTLC and bioautography was an ideal tool for screening bioactive compounds in complex biological matrix.

HPTLC–densitometric and HPTLC–MS Methods for Analysis of Triterpenoids from Cucurbita maxima Peel

Fruits and vegetables are integral part of our day to day. They are the main source of food for the living system. Large amount of agro-waste generated from food industries and kitchen pertaining to biggest nutritional loss, environmental problems and economical implications. Even though pomace, peels, rind and seeds are considered a waste part of plant they are still rich source of valuable compounds like polyphenols, oils, enzymes, vitamins, fiber, etc. which is just adjunct to its different uses. Present study conducted on waste pumpkin peel. HPTLC fingerprint profile of pumpkin peel methanol extract was performed using HPTLC plate of silica gel 60 F254 as the stationary phase and Toluene: Chloroform: Ethanol (4:4:1 V/V/V) as the mobile phase. After development chromatogram was scanned at 254 nm and 366 nm by densitometric scanner. Anisaldehyde in sulphuric acid is used as a detecting reagent which gives pink-violet and/or giving blue coloration after derivatization of plate. Further HPTLC-MS analysis gives the confirmation to detected terpenoids. Therefore, this waste peel part of the pumpkin can be used in an ingenious way by further purification, isolation and characterization.

HPTLC AND FIRST DERIVATIVE UV-SPECTROPHOTOMETRIC METHODS FOR ESTIMATION OF VILAZODONE IN PHARMACEUTICALS

A new HPTLC method and a sensitive UV spectrophotometric method were established for estimating vilazodone hydrochloride in its pharmaceutical formulations. An environment-friendly chromatographic mobile phase consisting of ethyl acetate: toluene: formic acid (5:4:1, V/V/V) along with ultraviolet densitometric detection at 240 nm using pre-coated silica gel plates was used. First derivative UV spectrophotometric determinations were performed using methanol as solvent, and amplitudes were measured for quantification purposes. Validation studies were compliant with ICH guidance. Vilazodone shows an optimum Rf value of 0.73 ± 0.02 by HPTLC method. First derivative spectrophotometric measurements were done at 230 nm (peak) and 247 nm (valley), respectively. Best method linearity was observed in the range of 100 - 600 ng band-1 and 100 - 600 ng mL-1 for the chromatographic and spectrophotometric methods, respectively. Method detection limits were 61.4 ng band-1 and 36.03 ng mL-1, for chromatography and spectrophotometry, respectively. Higher % recovery (&gt; 99 %) of vilazodone from the in-house formulation satisfied study intent as well as instituted selectivity of both the methods. Both the newly developed methods have the potential of application in routine quantification of vilazodone in pharmaceuticals.

A dual-functional chemosensor based on acylhydrazone derivative for rapid detection of Zn(II) and Mg(II): Spectral properties, recognition mechanism and application studies

In this work, an acylhydrazone derivative (QN62) was developed via the one-step condensation of 6-hydroxy-2-naphthoic hydrazide with quinoline-8-carboxaldehyde. The structure of the QN62 compound was characterized by 1H NMR, 13C NMR, HR-MS (ESI), and X-ray crystallography. As a dual-functional turn-on fluorescence chemosensor, QN62 exhibited rapid recognition for Zn2+ in DMSO-H2O (4:1, v/v) and Mg2+ in ethanol-H2O (9:1, v/v). The enhancement in fluorescence detection was associated with the coordination reaction between QN62 and the target ions, which promoted intramolecular charge transfer and prevented the CN isomerization process. Simultaneously, a rapid color change from colorless to yellowish-green or yellow under UV light (365 nm) was easily visible to the naked eye. Under optimal conditions, the limit of detection and limit of quantification were 32.3 nM and 97.8 nM for Zn2+ and 16.1 nM and 48.9 nM for Mg2+, respectively. The recognition mechanism was reasonably speculated based on analysis of the Job’s plot, HR-MS, 1H NMR, and density functional theoretical calculations. Utilizing silica-gel plates fabricated from the QN62 chemosensor, the visual and rapid identification of Zn2+ and Mg2+ was successfully achieved, which could provide a convenient approach for on-site detection in environmental fields. The QN62 chemosensor could also quantify trace amounts of Zn2+ and Mg2+ in water samples. Furthermore, the cell imaging experiments indicated that QN62 could effectively sense intracellular Zn2+ and Mg2+, providing potential applications in biological systems.

Novel Stability-Indicating TLC-Densitometric Method for Quantification of Antazoline and Tetryzoline; Application to Pharmaceutical Formulation

Ophthalmic pharmaceutical preparation containing antazoline hydrochloride (ANT) and tetryzoline hydrochloride (TET) is prescribed widely as an over the counter (OTC) medication to treatment allergic conjunctivitis and their determination in presence of their degradation products is a major challenge. A novel sensitive, selective, and precise thin-layer chromatographic method established to determination both ANT and TET in both bulk drugs, formulation, and in presence of their degradation products with the elucidation of degradate's structures. Upon using silica gel plates and means of a developing system using ethyl acetate: ethanol: ammonia (8: 2: 0.1, by volume) the studied drugs separation was achieved, and scanning was carried out at 220.0 nm for the separated bands with a 0.2–18.0 µg/band concentration range for each of ANT and TET. Optimum separation was achieved with values Rf of 0.42 and 0.69, for TET and ANT, respectively. Additionally, the studied drugs' stock solutions were imperiled to different stress conditions. Both drugs were found to be vulnerable to alkaline hydrolysis as well as oxidative degradation showing well resolved degradation products' peaks. While they held out against acidic, thermal and photo degradation. Mass spectrometry was employed to elucidate the degradates' structures. Validity was applied for the proposed method with respect to all validation parameters. Effectively the method was applied to estimate the cited drugs' in marketed ophthalmic formulation.

An ecofriendly multi-analyte high performance thin layer chromatographic densitometric determination of amoxicillin, metronidazole, and famotidine in their ternary mixtures and simulated gastric juice: A promising protocol for eradicating Helicobacter pylori.

Gastrointestinal tract disorders constitute a heavy burden to healthcare providers.To eradicate Helicobacter pylori infection, different triple therapy protocols have been proposed. Among which are combinations of proton pump inhibitors (e.g. omeprazole), histamine-2 receptor antagonists (e.g. famotidine), along with antibiotics (e.g. amoxicillin). In this work, a sensitive and accurate high performance thin layer chromatographic method was developed for the simultaneous determination of amoxicillin, metronidazole, and famotidine in bulk powder and laboratory prepared combined-tablet mixtures. Complete separation of the cited compounds was achieved using pre-coated silica gel plates with a mixture of methanol: chloroform: toluene: water: glacial acetic acid (5:2:1.5:0.5:0.1 v/v/v/v/v) as the mobile phase. The method was fully validated as per the international conference of harmonization guidelines. Good linearity, correlation coefficient of 0.9991, was obtained in the concentration ranges 0.1-1.6 μg band-1 (amoxicillin), 0.1-0.9 μg band-1 (metronidazole) and 0.1-0.9 μg band-1 (famotidine). Since the method allowed the determination of the three compounds in combined tablets with high degree of selectivity, accuracy, precision, with cost-effectiveness, it could be used for regular quality control. Moreover, the applicability of the proposed method was extended to the determination of the ternary mixture in simulated gastric juice. Method greenness was assessed using different green metrics. This article is protected by copyright. All rights reserved.

Comparative study of extension area based methods for spectrophotometric determination of desmopressin acetate in the presence of its acid-induced degradation products

Desmopressin acetate (DPA) is a synthetic analogue of vasopressin used in the treatment of diabetes insipidus, bedwetting, hemophilia A, and elevated levels of urea in the blood. Sensitive and selective stability-indicating methods are needed to be developed and validated for its assay pure and pharmaceutical dosage forms in the presence of its degradation products as no method has been reported for its determination in the presence of its degradants. This work describes a comparative study of five simple stability-indicating spectrophotometric techniques for determination of DPA in presence of its acid-degradation products (acid-degradants) without prior separation. The proposed spectrophotometric techniques (First derivative, Derivative ratio, Ratio difference, Mean centering and Dual wavelength) were developed and validated according to ICH guidelines. Acid degradation was carried out with 0.1 N HCl; the acid-degradants were separated on TLC plates and the acidic degradation pathway was established by IR, H-NMR and MS techniques. The TLC method was based on the separation of DPA and its acid-induced degradation products on silica gel plates using methanol: water (80:20, v/v) as a developing system and UV detection at 254 nm. All assay suggested methods were successfully applied for quantitation of DPA in pure and tablet forms. They are specific, sensitive, precise and accurate. They showed good linearity in the concentration range of 1–14 µg/mL with good correlation coefficients, and limit of detection (LOD) of 0.304, 0.274, 0.167, 0.248 and 0.199 and limit of quantitation (LOQ) of 0.920, 0.829, 0.506, 0.751 and 0.604) for each method, respectively. These methods were successfully applied for the simultaneous determination of DPA in its pure and tablet dosage form in the presence of its acid-degradants. The results obtained were statistically comparable with those of reported HPLC assay method; no significant differences were observed with relevance to accuracy and precision. All the methods are sensitive, selective and can be used for the routine analysis of DPA in its pure and dosage forms.

Нокаут генов α-, β-, и γ-синуклеинов у мышей приводит к изменению содержания ряда липидов в печени и плазме крови

In addition to the role of synuclein proteins in synaptic transmission through binding with lipid membranes, the function of synucleins in reactions of the synthesis of lipids and fatty acids is also widely studied. Studying the disruption of lipid metabolism in Parkinson’s disease caused by synuclein dysfunction is particularly interesting. The aim of the study: To determine the effect of the absence of synuclein family proteins on the total lipid content and the ratio of different lipid classes in the liver and blood plasma in transgenic mice. Materials and methods: Measurement of lipid classes of αβγ-synuclein triple knockout mice (N=6) and wild type controls (N=6) was performed by the HPLC on the silica gel plates. Results: A 1.4-fold (P&lt;0.05) increase in the percentage of total polar lipids was detected in the liver of knockout mice compared with the wild type, while the relative content of triglycerides decreased 1.2-fold (P&lt;0.05), respectively. At the same time plasma levels of the polar lipids and triacylglycerols were unaltered. The lack of synucleins causes changes in the levels of fatty acids in comparison to wild type animals: C16:0 levels increased 1.2-fold in the liver (P&lt;0.05) and 1.8-fold in plasma (P&lt;0.05), and C18:1n9 levels increased both 1.4-fold (P&lt;0.05) in plasma and 1.2-fold in the liver (P&lt;0.05). C20:4n6 levels decreased 1.5-fold (P&lt;0.05) in the liver of nonsynuclein mice. C18:2n6 levels decreased 7-fold in plasma (P&lt;0.05), but did not change in liver. Conclusion: Our data demonstrate that the absence of all three members of the synuclein family causes disruption of lipid metabolism and leads to altered synthesis of fatty acids and hepatic lipid accumulation.

IDENTIFIKASI KUALITATIF FENOLIK DAN PENAPISAN AKTIVITAS PEREDAMAN RADIKAL DPPH MENGGUNAKAN KLT PADA EKSTRAK BATANG Pluchea indica L.

Pluchea indica L. (beluntas) from the Asteraceae is a plant known to be rich in phenolics. Studies on the phenolic content of P. indica stems have not been explored much. The purpose of this study is to qualitatively identify the presence of phenolic compounds and to screen for the radical scavenging ability of DPPH in P. indica stem extracts using the TLC method. Extraction was carried out with the ultrasonic directly and sequentially using 50% ethanol as solvent. Separation was carried out on a silica gel plate GF254 with ethyl acetate: water: formic acid: toluene (20:2:2:1) as the mobile phase. Gallic acid and chlorogenic acid were used as comparisons. Identification of the presence of phenolic using FeCl3 5% as a spray reagent, while screening for radical scavenging activity using DPPH 0.1 mM as a spray reagent. The results showed that the 50% ethanol extracts of P. indica stems, both obtained from direct and stratified extraction, indicated the presence of phenolic compounds as antioxidants. The phenolic compounds detected were identical to gallic acid and chlorogenic acid, respectively, at hRf values of 89.4 and 55.3. The development of phenolic utilization from P. indica stems as a source of antioxidants still needs to be studied.

Determination of β-blocking receptor drugs in silica gel TLC systems with the mobile phase containing surfactant

Abstract Eight drugs blocking beta-adrenergic receptors activity (acebutolol, alprenolol, atenolol, oxprenolol, labetalol, metoprolol, propranolol and sotalol) were investigated through the use of the thin-layer technique with its mobile phase containing surfactant. Assessment of the effect of surfactant presence and 1-propanol concentration in the mobile phase on the retention and separation of investigated solutes was then carried out wherein the effect of the surfactant concentration on the zone shape properties (asymmetry and tailing coefficient) was investigated. The method was applied for the quantitative analysis of the chosen solutes, and the LOD and LOQ values of chosen were determined. These were as follows: acebutolol – 1.11 and 3.36 μg/spot, metoprolol 1.45 μg/spot, 4.4 μg/spot. The chosen system is environmentally friendly due to using silica gel plates and only 5% of propanol in water.

Experiments and Simulation on the Performance of a Liquid-Cooling Thermal Management System including Composite Silica Gel and Mini-Channel Cold Plates for a Battery Module

Lithium batteries in the electric vehicles (EVs) reveal that the operating temperature and temperature uniformity within the battery pack significantly affect its performance. An efficient thermal management system is urgently needed to protect the battery module within suitable temperature range. In this study, the composite silica gel (CSG), coupled with cross-structure mini-channel cold plate (MCP) as the cooling system, has been proposed and applied in a battery module, which can provide a reliable method of controlling battery temperature with low energy consumption. The experimental and simulation results reveal that a composite silica gel-based liquid system can control the temperature below 45 °C and maintain the temperature difference within 2 °C at a 3C discharge rate. Besides, the CSG, coupled with the structure of reciprocal chiasma channels for the battery module, presents an optimum temperature-controlling performance among various cooling structures during the charge and discharge cycling process. This research is expected to provide significant insights into the designing and optimization of thermal management systems.