Analysis of 19-nortestosterone residue in animal tissues by ion-trap gas chromatography-tandem mass spectrometry

Veterinary Drug Residues in the Food Chain as an Emerging Public Health Threat: Sources, Analytical Methods, Health Impacts, and Preventive Measures

Veterinary medications are necessary for both contemporary animal husbandry and food production, but their residues can linger in foods obtained from animals and pose a dangerous human risk. In this review, we aim to highlight the sources, occurrence, human exposure pathways, and human health effects of drug residues in food-animal products. Following the usage of veterinary medications, pharmacologically active compounds known as drug residues can be found in food, the environment, or animals. They can cause major health concerns to people, including antibiotic resistance development, the development of cancer, teratogenic effects, hypersensitivity, and disruption of normal intestinal flora. Drug residues in animal products can originate from variety of sources, including water or food contamination, extra-label drug use, and ignoring drug withdrawal periods. This review also examines how humans can be exposed to drug residues through drinking water, food, air, and dust, and discusses various analytical techniques for identifying these residues in food. Furthermore, we suggest some potential solutions to prevent or reduce drug residues in animal products and human exposure pathways, such as implementing withdrawal periods, monitoring programs, education campaigns, and new technologies that are crucial for safeguarding public health. This review underscores the urgency of addressing veterinary drug residues as a significant and emerging public health threat, calling for collaborative efforts from researchers, policymakers, and industry stakeholders to develop sustainable solutions that ensure the safety of the global food supply chain.

Simple and Accurate HPTLC-Densitometric Method for Assay of Nandrolone Decanoate in Pharmaceutical Formulation

This study reports the development and validation of a new, simple, and accurate high-performance thin-layer chromatography (HPTLC)-densitomeric method for the determination of nandrolone decanoate in a commercially available injection formulation. Chromatographic analysis was performed on glass CN modified silica gel 60F₂₅₄ plates developed using n-hexane-ethyl acetate in volume ratio 42.5:7.5 as the mobile phase. Densitometric scanning was carried out at the wavelength of 245 nm. This chromatographic system gave compact spot and a symmetrical peak of nandrolone decanoate with retardation factor (R_F) value at 0.57 (±0.02). The linearity of this method with the high correlation coefficient of calibration plot ranges from 0.780 to 12.500 μg/spot. The developed method is characterized by good precision (coefficient of variation CV < 2%) and high accuracy close to 100.3% (R = 99.0%). Values of limits of detection and quantification equal to 0.231 and 0.700 μg/spot, respectively, confirm the sensitivity of the developed method. The analysis of the pharmaceutical formulation of nandrolone decanoate indicates drug content of 50.5 mg/mL and 101.0% in relation to the label claim. This is in good agreement with the recommendation of the International Council for Harmonisation (ICH) guidelines as well as the pharmacopoeial requirements. The low CV value (<1%) of nandrolone decanoate content in the tested injection formulation confirms the suitability of the proposed HPTLC-densitometric method for routine control of this compound in examined pharmaceuticals.

Monoclonal antibody-based ELISA and colloidal gold immunoassay for detecting 19-nortestosterone residue in animal tissues

This article presents the generation of monoclonal antibodies (mAbs) with high specificity against 19-nortestosterone (NT) through cell fusion techniques and the development of a mAb-based indirect competitive ELISA (icELISA) method and colloidal gold-based immuno-chromatographic assay to detect NT residues in beef and pork samples. A modified carbodiimide method was employed to synthesize the artificial antigen, and BALB/c mice were used to produce anti-NT mAbs. On the basis of the checkerboard titration, an indirect competitive ELISA standard curve was established. This assay was sensitive and had a linear range from 0.03 to 38 ng/mL in phosphate buffered saline (PBS), with IC(50) and LOD values of 0.52 ng/mL and 0.01 ng/mL, respectively. Of all the competitive analogues, the produced mAb exhibited a high cross-reactivity to 17α-nortestosterone (83.6%), the main metabolite of NT in animal tissues. Except for moderate cross-reactivities with trenbolone (22.6%) and β-boldenone (13.8%), the other interference to the assay was negligible (<0.05%). In contrast, the strip test had a visual detection limit of 1 ng/mL in PBS, 2 μg/kg in beef, and 2 μg/kg in pork, respectively, and the results can be judged within 10 min. The ELISA and GC-MS results showed close correlation in beef (R2=0.9945) and in pork (R2=0.9977). Therefore, the combination of two immunoassays provides a useful screening method for quantitative or qualitative detection of NT residues in animal-origin products.