Depletion of Veterinary Pharmaceuticals and Radiometric Analysis of their Residues in Animal Matrices

Research is required to study and evaluate the metabolism and residue depletion kinetics of a priority list of veterinary drugs used in food-producing animals that several IAEA Member States have no data to facilitate the setting of internationally acceptable standards (MRLs) and address pertinent public health and trade bottlenecks.
 
Setting MRLs in Member States at an international level requires data sets, including residue depletion to facilitate risk assessment by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The depletion rates are estimated using radiolabeled drugs in target animals. Such data is lacking for many Member States and there is an urgent need to address the gap and facilitate developing dossiers and JECFA evaluations. Due to urgent calls by several developing country Member States, supported by a number of developed countries, the 24th Codex Committee for Residues of Veterinary Drugs (CCRVDF) in foods in May 2018 (FAO/WHO, 2018) identified some priority compounds for immediate attention including (but not limited to): a) Amoxicillin in goats, poultry; b) Ampicillin in cattle, pig, horse, goats, sheep, fish, poultry; c) trypanocides e.g. Diminazene in sheep, goats; d) Imidocarb in horse; Ivermectin in horse, goats, camel, poultry; e) Oxytetracyline in honey, camel, horse, and goats. These compounds and animals are a starting point for further work that will greatly help Member States overcome the challenge of limited contribution to the setting of international standards that impact their public health and trade.
 
Research studies on metabolism of veterinary drugs help identify and quantify the nature of the residues (VICH, 2012) and such evaluation ensures that food from animals treated with veterinary pharmaceuticals is safe for consumers. These studies generate data for instance on: (1) total residues,  (2) the depletion of drug residues from edible tissues at varying time intervals following administration, (3) metabolic profile, detailed understanding of the individual components/residues of concern, (4) marker residue(s) for compliance/regulatory purposes and monitoring of appropriate drug used, and (5) identification of target tissue (s) relevant to national or regional monitoring/regulatory programs (VICH, 2012).
 
The studies in food-producing animals require use of radiolabeled drugs which are rare among developing Member States, who thus depend largely on others or entirely on the private sector.
 
Objectives
 
To support Member States in setting safe/guideline levels for veterinary drug residues in foods through disposition studies of radiolabeled substances in food producing animals, thus contributing to safeguarding consumers and promoting trade.
 
This CRP, an extension of another project on mixed residues/contaminants in foods, is in line with the Food and Environmental Protection sub-programme objective 2.1.3: to improve food safety and food control systems. The project will help the sub-programme meet its goal of facilitating consumer protection and trade. National or internationally permitted/recommended levels influence trade in food stuff and those set by the Codex Alimentarius Commission (international food code) serve as a reference point for the WTO. The project will focus on enhancing research capabilities and production of scientifically reliable information in Member States in the area of veterinary pharmaceuticals and to determine residues of these substances in food producing animals. It will help Member States to provide data to JECFA for the risk assessment and subsequent establishment for MRLs.