An easy and short-time TLC-densitometric method was developed for the separation of metronidazole, secnidazole, ornidazole, tinidazole, and 2-methyl-5-nitroimidazole and for the determination of metronidazole and tinidazole in Metronidazole Polpharma and Tinidazolum Polpharma tablets. Analyzes were performed on chromatographic plates precoated with silica gel 60F254 using the optimal mobile phase: chloroform + methanol + diethylamine in a volume ratio of 9:1:1. The method has been validated. The intraday and interday precision values for the three different concentrations ranged from 0.99% to 1.48% and 0.89% to 1.76%, and the precision values ranged from 1.13% to 2.48% and 0.95% to 2.49% for metronidazole and tinidazole, respectively. The limit of quantification (LOQ) was 0.036 and 0.066 µg/spot for metronidazole and tinidazole, respectively. The mean recovery was 103.1% and 100.6% for metronidazole and tinidazole, respectively. The content of metronidazole and tinidazole in tablets in relation to the content declared by the manufacturer was 101.3% and 99.8%, respectively. The obtained results were verified using the pharmacopoeial method. The presented method is fast, sensitive, precise, selective, accurate and robust. It allows for the analysis of several samples on one chromatography plate at the same time.

The analysis of drugs is a priority in public health, particularly antibiotics which develop resistance due, among other things, to bad dosages or poor quality of the active substance. In this study, we evaluated eight antibiotics available in health centers in Djibouti through qualitative and quantitative analysis. The tests were based on high-purity reference products. In qualitative analysis by HPLC, only amoxicillin presented two impurity peaks. This observation is found in the dosage of this active ingredient with a value of 83 ±0.6 mg instead of the 500 mg indicated on the label. It will be necessary to diversify the sample’s provenance to seek the origin of this degradation.

Leucobryum is a moss genus that exhibits various bioactivities. However, the identification of Leucobryum species with morphology alone remains difficult. Nowadays, chemical profile analysis provides additional tools for plant classification, especially in medicinal plants. This method uses chemical similarities to identify the differences among some plants, especially for the different varieties of the same species. The objective of this study was to obtain the chemical profiles and use chemometrics to identify selected Leucobryum species found in Thailand. Lipophilic extracts from 18 samples of five taxa were analyzed with TLC and HPLC. Cluster analysis and PCA were used to investigate the similarities of the chemical profiles. PERMANOVA was performed to determine the difference among taxa. The results showed that the TLC profile could separate only the genus of the sample, while HPLC chromatograms showed separation among the Leucobryum taxa and consistent patterns within the same species. In addition, the chemical profiles of Leucobryum species were separated at the species level in PCA. The PERMANOVA showed significantly different profiles among the species (P = 0.002). Therefore, this work illustrated the potential of chemometrics as supporting evidence for species delimitation in the moss genus Leucobryum.

Artic root is a well-known plant adaptogen with multipotential pharmacological properties. Thin-layer chromatography (TLC) – screening followed by diode-array high-performance liquid chromatography and nuclear magnetic resonance spectroscopy proved to be a reliable and convenient method for simultaneous determination of quality of various herbal raw materials and supplements. This combination allowed for comparing and differentiating arctic root samples as well as defining their authenticity. The study provided information on the chemical and biological properties of the seven chosen samples as well as qualitative and quantitative evaluation of the quality markers: rosavin, salidroside, and p-tyrosol. The absence of rosavin, salidroside, and p-tyrosol in three samples was detected using TLC-screening and confirmed by HPLC-DAD and NMR. The paper highlighted the importance of quality control and strict regulation for herbal medicine supplements and preparations.

TLC and HPTLC in normal (NP) and reversed (RP) phase systems combined with densitometry were used to analyze caffeine, propyphenazone and paracetamol. Normal phase analyses were performed on five different stationary phases (chromatographic plates), testing three mobile phases. Reversed-phase analyses were performed on four different chromatographic plates using three mobile phases. Thus, it was checked whether analyses using TLC chromatographic plates could be as sensitive as those performed on HPTLC plates. For all analyzed biologically active substances, the limit of detection (LOD) was calculated, i.e. a parameter that describes the method sensitivity. It has been shown that using both TLC and HPTLC plates, it is possible to develop chromatographic conditions that enable the detection of caffeine, propyphenazone and paracetamol in amounts ranging from a dozen to several dozen µg/spot. In the reversed-phase (RP) system, lower LOD values for all tested compounds were obtained using TLC than HPTLC. However, using analyses in the normal phase system (NP), similar (of the same order) LOD values are obtained for caffeine, propyphenazone and paracetamol, both when using TLC and HPTLC plates. Therefore, for economic reasons, TLC plates should be recommended for analyses of caffeine, propyphenazone and paracetamol, which are several times cheaper than HPTLC plates.

The interest in lipid composition profiling is significantly increasing as research reveals the immense importance of lipids in medicine, plant science, food and agriculture. However, lipidomic analysis requires high-end specialty equipment. We used two-dimensional thin-layer chromatography (2D TLC) as a readily available, low-cost tool for basic lipidomic profiling of lipid classes in algal samples as model: Chlamydomonas reinhardtii, Auxenochlorella protothecoides, and Euglena gracilis. Algal lipid extracts were separated on a 2D-TLC plate, and TLC analysis was followed by scraping individual TLC spots off the plate, and a subsequent liquid chromatography separation and tandem mass spectrometry (LC-MS/MS) analysis. For comparison, crude lipid extracts were also injected directly to the LC-MS/MS system. Lipid class annotation was achieved by a combination of accurate mass, retention time information, neutral loss and fragment ion analysis by MS2Analyzer, and by matching spectra to LipidBlast MS/MS library. Overall, we were able to identify 15 lipid classes, and to adequately profile the lipid classes in all three organisms. This TLC method is thus suggested as an accessible tool for lipid class profiling of algal, plant, and food lipids, alike, when a rapid and simple analysis is required, e.g., for screening purposes.

Numerous studies have shown that quinolones residues in the foods exceeding the MRL is harmful to the human health. There are some limitations in the existing methods for the residues, so we developed a new limit test method (TLC-SERS) to rapidly determine following residues: enrofloxacin(A), ciprofloxacin (B), ofloxacin(C), fleroxacin(D), sparfloxacin(E), enoxacin(F), gatifloxacin(G) and nadifloxacin(H). The residues can be preliminarily separated by TLC. Labeling the tested compounds’ position on the thin layer plate by their relative Rf under 254nm ultraviolet, and an appropriate amount of nanometer silver solution should be added to the position. The silver on the plate should be irradiated with 532nm laser to obtain SERS of the compounds. The results showed a significant differences of the 8 quinolones’ SERS; the LOD of the H, A, D, E, C, G, F and B were orderly 9.0, 12.6, 8.0, 19.0, 8.0, 8.4, 9.0 and 12.6 ng/mL, and the RSD≤4.9% for SERS of each quinolones.The limit test results of the 20 samples was consistent with that determined by the UPLC–MS/MS. The above results indicate that the TLC-SERS is specific, sensitive, stable, and accurate, providing a new reference for the rapid limit test of harmful residues in foods.

The aim of this paper is to present a comprehensive overview of the main aims and scopes in screening of botanicals, a task which thin-layer chromatography (TLC) is on an everyday basis confronted with and engaged in. Stunning omnipresence of this modest analytical technique (both in its standard format (TLC) and the high-performance one (HPTLC), either hyphenated or not) for many analysts might at a first glance appear chaotic and random, with an auxiliary rather than leading role in research, and not capable of issuing meaningful final statements. Based on these reflections, our purpose is not to present a general review paper on TLC in screening of botanicals, but a blueprint rather (illustrated with a selection of practical examples), which highlights a sovereign and important role of TLC in accomplishing the following analytical tasks: (i) solving puzzles related to chemotaxonomy of plants, (ii) screening a wide spectrum of biological properties of plants, (iii) providing quality control of herbal medicines and alimentary and cosmetic products of biological origin, and (iv) tracing psychoactive plants under forensic surveillance.

The quality of veterinary medicinal products (VMP) is essential for efficient disease management. Therefore, VMPs that do not meet the required standards of quality can lead to increased sickness, death, and the development of antimicrobial resistance, posing a danger to both animals and humans. This study aimed to identify substandard and falsified VMPs on the Rwandan market using the Global Pharma Health Fund (GPHF)-Minilab™. VMP samples were purchased and collected in a cross-sectional study from veterinary retail pharmacies from five districts in four provinces of Rwanda, during May and June 2023. These samples were transported to the Veterinary Laboratory of the School of Animal Sciences and Veterinary Medicine, Nyagatare campus, University of Rwanda, and stored until analysis. The samples were subjected to physical and chemical analysis following the GPHF-Minilab™’s guidelines. A total of 130 samples from two categories of VMP were purchased from 10 veterinary retail pharmacies in urban and rural areas. The results of this study revealed that none of the assessed VMP samples failed physical tests (visual inspection, weight verification, and disintegration test). 10 samples (Sulfamethoxazole/Trimethoprim) out of 130 (7.7%) passed the visual inspections but later failed to comply with Thin-Layer Chromatography result specifications. This is an indication of the presence of substandard and falsified VMP circulating in Rwanda that warrants regular inspection and chemical quality control of VMPs along the supply chain.

Consumption of milk contaminated with antibiotic residues above the maximum residue limit (MRL) causes direct toxicity to humans and the development of superbugs that leads to the failure of antibiotic therapy and threatens human life. Besides, long-duration exposure might alter the nature of gut microflora results in the enhancement of many diseases. Therefore, we examined 300 raw and processed packet milk samples using thin layer chromatography (TLC) and ultra high performance liquid chromatography (UHPLC) method against five veterinary antibiotics and assessed the risk for consumers in Chattogram, Bangladesh. Risk analysis was calculated by using hazard quotient on the basis of 165 ml per capita milk consumption. We found a total of 7% prevalence of antibiotic residues in raw milk samples which were higher (8%) in individual samples than the pooled samples (4%). However, we did not find any processed packet milk samples as positive. The mean concentration of oxytetracycline residue was detected 61.29 µg/l and amoxicillin was 124 µg/l in individual milk samples. Risk analysis showed the hazard quotient values of 0.0056 for oxytetracycline and 0.0017 for amoxicillin residue which was confirmed that, no significant health risk associated with the consumption of milk produced and marketed in the study area. Our study might fill the gap of knowledge to measure the safety status of milk regarding public health issues.

Seaweeds have been the target of much attention due to the known bioactivities of some of their compounds. Although many studies about the application of seaweeds in various areas are available, these data are mostly about the raw extracts and not about specific compounds, such as seaweeds pigments. Moreover, the fungal infections of the skin, nails and hair caused by dermatophytes, are the most common fungal infections in humans. These pathologies require long periods of topical and/or systemic treatment that are associated with adverse effects and contraindications. This study had two objectives, the first was to evaluate the possibility of isolating and characterizing the pigments of Calliblepharis jubata and Fucus vesiculosus; the second was to assess their antifungal activity. The extraction of pigments was performed using a method of extraction by exhaustion; the purification was carried out by column chromatography. Three techniques were used to characterize the pigments, thin layer chromatography (TLC), UV-visible spectrophotometry and Fourier-transform infrared spectroscopy (FTIR). The antifungal activity was evaluated using the micro-dilution method, following the EUCAST international standards, on three dermatophytes, Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis. It was possible to observe that the extract obtained from the seaweed C. jubata and F. vesiculosus, corresponding to the purified pigment phycobiliprotein, and the crude extract, an enriched extract, obtained from the seaweed C. jubata showed antifungal activity against the three fungal agents of human skin infection.

The objective of the study was to apply the principles of analytical quality by design (AQbD) to the analytical method for the determination of the radiochemical purity (PQR) of the radiopharmaceutical sodium iodide 131I oral solution, by means of thin layer chromatography (TLC) with a Radio-TLC scanner, the same one that allows to evaluate the quality of the product. For the AQbD, the analytical objective profile (ATP), critical quality attributes (CQA), risk management, the method operable design region (MODR) were defined through the response surface methodology for method optimization using the MINITAB ® software, Control Strategy and the validation of the method where the parameters of selectivity, linearity, precision, robustness, detection limit, quantification limit, range and stability of the sample solution were evaluated. Under the experimental conditions, the conditions of the method were demonstrated by TLC-Scanner and optimization was carried out for an injection volume of 3 µL, radioactive concentration of 10 mCi/mL and carrier volume of 40 µL. It was statistically demonstrated that the method is selective for the 131I iodide band Rf of 0,8 and for the radiochemical impurity IO₃⁻ Rf of 0.6, linearity from 6,0 to 22.0 mCi/mL, intermediate precision with Global RSD of 0,624%, robustness with global RSD 0,101%, detection limit of 0,09 mCi/mL, quantification limit of 0.53 Ci/mL, conforming range, and stability of the sample solution evaluated over time 0, 2 and 20 hours with a global RSD of 0,362%, obtaining consistent results. The development of the method based on AQbD allowed the generation of a design space and an operational space with knowledge of all the characteristics and limitations of the method, likewise in all the operations the conformity of the tests to the acceptance criteria was verified. The validity of our method is concluded under the established conditions, suitable for use in the manufacturing process of sodium iodide 131I and application in nuclear medicine services.

Human societies demand sustainable alternatives for goods and services. Plants are sustainable sources of important metabolites with beneficial impacts on human health. There are many reported methodologies and commercial suppliers for extract preparations from the plant Mucuna sp. They usually claim to be enriched in L-dopa, their distinctive metabolite. However, there are poor characterizations of the metabolite's components in that extracts. Here, we present the metabolite characterization of a Mucuna seed extract, emphasizing the L-dopa identification and quantification. To obtain the extracts, we follow a green and sustainable extraction protocol. The lyophilized extract was subject to liquid chromatography and mass spectrometry to identify its primary metabolites. Additionally, we follow thin-layer chromatography to identify some carbohydrates in the sample. The resultant extract has a 56% L-dopa. Other main components in the extract were arginine, stizolamine, and the fructooligosaccharides sucrose and nystose. The characterized Mucuna extract can be easily standardized as powder presentation and used in several biomedical applications.