Multiresidue analysis of tetracycline and β-receptor agonists in chicken by pressurized liquid extraction and liquid chromatography-tandem mass spectrometry: Comparison with QuEChERS extraction method and ultrasound assisted extraction

Strip biosensors based on broad-spectrum aptamers and cationic polymers for the on-site rapid detection of tetracycline antibiotics residues in milk

A lateral flow chromatography strip (LFS) is a chromatography-based biosensor with advantages of convenient portability, simple operation and rapid detection. In this study, a novel rapid detection technique of aptamer-based chromatography strip was developed and used for the first time for the residue detection of tetracycline antibiotics (TCs) in various milk samples. In this method, gold nanoparticles (AuNPs) modified by TCs specific aptamers were used as probes, and cationic polymers as capture molecules in a test line (T-line). Meanwhile, the analysis of the gray value of the T-line enabled a linear detection range of 1-300 nM and a limit of detection (LOD) of 0.33 nM for quantitative analysis. The biosensor demonstrated high specificity, good stability, and successfully detected tetracyclines in milk samples with recovery rate of 93.60%-106.20%. This method sets a basis for multi-residue antibiotics detection in diverse samples, showing potential for on-site applications.

Structure-activity relationship of pharmacophores and toxicophores: the need for clinical strategy

OBJECTIVES

Sometimes clinical efficacy and potential risk of therapeutic and toxic agents are difficult to predict over a long period of time. Hence there is need for literature search with a view to assessing cause of toxicity and less efficacy of drugs used in clinical practice.

METHOD

Hence literatures were searched for physicochemical properties, chemical formulas, molecular masses, pH values, ionization, receptor type, agonist and antagonist, therapeutic, toxic and structure-activity relationship of chemical compounds with pharmacophore and toxicophore, with a view to identifying high efficacious and relative low toxic agents. Inclusion criteria were manuscripts published on PubMed, Scopus, Web of Science, PubMed Central, Google Scholar among others, between 1960 and 2023. Keywords such as pharmacophore, toxicophore, structure-activity-relationship and disease where also searched. The exclusion criteria were the chemicals that lack pharmacophore, toxicophore and manuscripts published before 1960.

RESULTS

Findings have shown that pharmacophore and toxicophore functional groups determine clinical efficacy and safety of therapeutics, but if they overlap therapeutic and toxicity effects go concurrently. Hence the functional groups, dose, co-administration and concentration of drugs at receptor, drug-receptor binding and duration of receptor binding are the determining factors of pharmacophore and toxicophore activity. Molecular mass, chemical configuration, pH value, receptor affinity and binding capacity, multiple pharmacophores, hydrophilic/lipophilic nature of the chemical contribute greatly to functionality of pharmacophore and toxicophore.

CONCLUSION

Daily single therapy, avoidance of reversible pharmacology, drugs with covalent adduct, maintenance of therapeutic dose, and the use of multiple pharmacophores for terminal diseases will minimize toxicity and improve efficacy.

Pressurized Liquid Extraction: A Powerful Tool to Implement Extraction and Purification of Food Contaminants

Pressurized liquid extraction (PLE) is considered an advanced extraction technique developed in the mid-1990s with the aim of saving time and reducing solvent with respect to traditional extraction processes. It is commonly used with solid and semi-solid samples and employs solvent extraction at elevated temperatures and pressures, always below the respective critical points, to maintain the solvent in a liquid state throughout the extraction procedure. The use of these particular pressure and temperature conditions changes the physicochemical properties of the extraction solvent, allowing easier and deeper penetration into the matrix to be extracted. Furthermore, the possibility to combine the extraction and clean-up steps by including a layer of an adsorbent retaining interfering compounds directly in the PLE extraction cells makes this technique extremely versatile and selective. After providing a background on the PLE technique and parameters to be optimized, the present review focuses on recent applications (published in the past 10 years) in the field of food contaminants. In particular, applications related to the extraction of environmental and processing contaminants, pesticides, residues of veterinary drugs, mycotoxins, parabens, ethyl carbamate, and fatty acid esters of 3-monochloro-1,2-propanediol and 2-monochloro-1,3-propanediol from different food matrices were considered.

Quick and high-throughput quantification of 22 β-agonists residues in animal-derived foods using enzymatic probe sonication

A high demand exists in veterinary drug residual analysis for rapid, automatic and high-throughput analytical techniques that produce data simultaneous and faster. Here, we describe a combined automated solid-phase extraction (SPE) and enzymatic probe sonication (EPS), subsequently ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the quick extraction, automated clean-up as well as simultaneous quantification of 22 β-agonists residues in animal-derived foods. Enhanced by the ultrasonic probe, only 2 min was needed for exhaustively extraction of β-agonists from foods of animal-origin; whereas traditional enzymatic digestion methods require hours or even days, which making it more appropriate for high-throughput biomonitoring. Moreover, the clean-up and pre-concentration procedures were conducted on the automatic SPE, which allowed 36 samples being performed simultaneously within 30 min. The method was successfully applied for analyzing 56 animal-derived food samples, 53.6 % of which contained detectable levels of at least one kind of β-agonists. Interestingly, both the detection rate and residual level of β-agonists in the ruminants (bovine and sheep) were higher as compared with the swine. Concerning the real food samples analyzed, the findings of this study suggest that stricter measures should be adopted to control the illegal usage of β-agonists on the farm animals, particularly for the ruminants.

Tetracyclines in the environment: An overview on the occurrence, fate, toxicity, detection, removal methods, and sludge management

Tetracyclines (TCs) are a group of broad-spectrum antibiotics having vast human, veterinary, and aquaculture applications. The continuous release of TCs residues into the environment and the inadequate removal through the conventional treatment systems result in its prevalent occurrence in soil, surface water, groundwater, and even in drinking water. As aqueous TCs contamination is the tip of the iceberg, and TCs possess good sorption capacity towards soil, sediments, sludge, and manure, it is insufficient to rely on the sorptive removal in the conventional water treatment plants. The severity of the TCs contamination is evident from the emergence of TCs resistance in a wide variety of microorganisms. This paper reviews the recent research on the TCs occurrence in the environmental matrices, fate in natural systems, toxic effects, and the removal methods. The high performance liquid chromatography (HPLC) determination of TCs in environmental samples and the associated technology developments are analyzed. The benefits and limitations of biochemical and physicochemical removal processes are also discussed. This work draws attention to the inevitability of proper TC sludge management. This paper also gives insight into the limitations of TCs related research and the future scope of research in environmental contamination by TCs residues.