Veterinary Drug Residue

Veterinary drugs residues are used within animal husbandry to cure and prevent diseases, and also to increase weight gain and tranquilize during transportation. Veterinary drugs are a complex group of substances with a couple of hundred actives belonging to different chemical classes and therapeutic areas, e.g. antibiotics, anti -parasitics, non-steroidal anti-inflammatory drugs (NSAIDs), such as phenylbutazone, hormones and, beta-agonists. These substances may leave residues in food derived from treated animals.

Data on the presence of residues of veterinary medicines and contaminants in animals and animal-derived food show high rates of compliance with recommended safety levels in the European Union, according to EFSA’s latest report. The report summarizes monitoring data collected in 2018.The percentage of samples that exceeded maximum levels was 0.3%. This figure is within the range of 0.25%-0.37% reported over the previous 10 years.

However, recent reports have revealed that the use of antimicrobial drugs in large amounts and consistently could result in deposition of antimicrobial residues in muscle and organs of animal. Consumption of these residues in animal products (especially through Fish and Fish Products, meat and meat products, Milk, egg, Honey, etc..,) may cause health risk to consumers including development of antibiotic resistance and hypersensitivity reaction, such as allergy.

In order to curtail this, different countries are setting different regulatory limits (MRPL/MRL). The comprehensive risk-orientated veterinary drug residue testing package includes screening and confirmatory methods for more than 250 active substances, including antibiotics, antiparasitics, hormones, β-agonists, endocrine disruptors and non-steroidal anti-inflammatory drugs. The method portfolio from single substance to multiclass analysis and screening methods can be applied to all relevant food and feed matrices

Main Analytical Parameters for Drug Residue Analysis:

Antibiotics and antiparasitics: more than 120 actives, including avermectins, amphenicoles, Nitrofurans, benzimidazoles, coccidiostats, quinolones, beta-lactames, macrolides, nitroimidazoles, sulfonamides, tetracyclines, triphenylmethane dyes. Non-steroidal anti-inflammatory drugs (NSAIDs), including phenylbutazone. Hormones and hormone analogues, more than 50 actives including steroid hormones, thyreostats, stilbenes, resorcyclic acid lactones and beta-agonists.

Eurofins offers the most comprehensive range of screening methods from single substance testing to risk-orientated multi-class testing for the full range of veterinary drug residues in trace amounts.

The Eurofins Competence Centre for Veterinary Residue Testing in Hamburg (Eurofins WEJ Contaminants) is one of the leading laboratories in the area of veterinary drug residue testing with many years of experience. Eurofins applies the whole range of modern analytical technologies, such as High-Resolution LC-MS, LC-MS/MS, Immunoassays, etc.

The screening methods such as Lateral Flow and ELISA can be used for quick screening of large volumes of samples, but not considered as a confirmation. The higher end testing methods such UPLC, LC MSMS are used for confirmatory methods, when it comes for import, export or any other litigations.

Some of the frequently tested antibiotic groups and their mode of action:

Amphenicols:

Amphenicols are a class of antibiotics with a phenylpropanoid structure. They function by blocking the enzyme peptidyl transferase on the 50S ribosome subunit of bacteria. Examples of amphenicols include chloramphenicol, thiamphenicol, azidamfenicol and florfenicol. The first-in-class compound was chloramphenicol, introduced in 1949. Chloramphenicol was initially discovered as a natural product, but all amphenicols are now made by chemical synthesis

Nitrofurans:

Nitrofurans are a class of drugs typically used as antibiotics or antimicrobials. The defining structural component is a furan ring with a nitro group. Members of this class of drugs include: Antibacterials (antibiotics) Difurazone (also known as Nitrovin) — an antibacterial growth promoter used in the animal feeds. The metabolites the parent molecule such as AOZ, AMOZ, SEM, AHD are also a growing concern currently.

Tetracyclines 

Tetracyclines are a group of broad-spectrum antibiotic compounds that have a common basic structure and are either isolated directly from several species of Streptomyces bacteria or produced semi-synthetically from those isolated compounds. Tetracyclines are named for their four ("tetra-") hydrocarbon rings ("-cycl-") derivation ("-ine"). While all tetracyclines have a common structure, they differ from each other by the presence of chloride, methyl, and hydroxyl groups. These modifications do not change their broad antibacterial activity, but do affect pharmacological properties such as half-life and binding to proteins in serum

Sulfonamides:

Sulfonamide is a functional group (a part of a molecule) that is the basis of several groups of drugs, which are called sulphonamides, sulfa drugs or sulpha drugs. The original antibacterial sulfonamides are synthetic (nonantibiotic) antimicrobial agents that contain the sulfonamide group. Some sulfonamides are also devoid of antibacterial activity, e.g., the anticonvulsant sultiame. The sulfonylureas and thiazide diuretics are newer drug groups based upon the antibacterial sulfonamides. Allergies to sulfonamides are common. The overall incidence of adverse drug reactions to sulfa antibiotics is approximately 3%, close to penicillin; hence medications containing sulfonamides are prescribed carefully.

Sulfonamide drugs were the first broadly effective antibacterials to be used systemically, and paved the way for the antibiotic revolution in medicine

Quinolone:

A quinolone antibiotic is a member of a large group of broad-spectrum bacteriocidals that share a bicyclic core structure related to the substance 4-quinolone. They are used in human and veterinary medicine to treat bacterial infections, as well as in animal husbandry. Nearly all quinolone antibiotics in use are fluoroquinolones, which contain a fluorine atom in their chemical structure and are effective against both Gram-negative and Gram-positive bacteria. One example is ciprofloxacin, one of the most widely used antibiotics worldwide

Avermectins:

The avermectins are a series of drugs and pesticides used to treat parasitic worms and insect pests. They are a group of 16-membered macrocyclic lactone derivatives with potent anthelmintic and insecticidal properties. These naturally occurring compounds are generated as fermentation products by Streptomyces avermitilis, a soil actinomycete. Eight different avermectins were isolated in four pairs of homologue compounds, with a major (a-component) and minor (b-component) component usually in ratios of 80:20 to 90:10. Other anthelmintics derived from the avermectins include ivermectin, selamectin, doramectin, eprinomectin, and abamectin

β-lactams:

The β-lactam ring is part of the core structure of several antibiotic families, the principal ones being the penicillins, cephalosporins, carbapenems, and monobactams, which are, therefore, also called β-lactam antibiotics. Nearly all of these antibiotics work by inhibiting bacterial cell wall biosynthesis. This has a lethal effect on bacteria, although any given bacteria population will typically contain a subgroup that is resistant to β-lactam antibiotics. Bacterial resistance occurs as a result of the expression of one of many genes for the production of β-lactamases, a class of enzymes that break open the β-lactam ring. More than 1,800 different β-lactamase enzymes have been documented in various species of bacteria.[4] These enzymes vary widely in their chemical structure and catalytic efficiencies.[5] When bacterial populations have these resistant subgroups, treatment with β-lactam can result in the resistant strain becoming more prevalent and therefore more virulent. β-lactam derived antibiotics can be considered as one of the most important antibiotic classes but prone to clinical resistance. β-lactam exhibits its antibiotic properties by imitating the naturally occurring d-Ala-d-Ala substrate for the group of enzymes known as penicillin binding proteins (PBP), which have as function to cross-link the peptidoglycan part of the cell wall of the bacteria

Coccidiostats:

Coccidiostats are antiprotozoal agents that act on coccidia parasites by inhibiting reproduction and retarding the development of the parasite in a host cell. They are most commonly used in poultry populations by addition in the feed at the authorized levels and observing the prescribed hygiene requirements.

Major list of antibiotic & veterinary drugs that been regulated under FSSAI regulation:

The MRL differ from matrix to matrix

Major list of antibiotic & veterinary drugs that Eurofins analyze:

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