Multi-class and multi-residue analyses are very complex procedures because of the physico-chemical properties of veterinary drug residues and other contaminants. The purpose of the study was to develop an analytical method for the sensitive determination of 69 analytes in bovine milk by liquid chromatography electrospray ionisation–tandem mass spectrometry. Antimicrobial, anabolic hormone, lactone, β-agonist, mycotoxin and pesticide residues were analysed in 120 raw milk samples from different dairy farms in North Macedonia. Stable isotopically labelled internal standards were used to facilitate effective quantification of the analytes. The linear regression coefficients were higher than 0.99, the limits of detection ranged from 0.0036 to 47.94 μg/L, and the limits of quantification ranged from 0.053 to 59.43 μg/L. The decision limit values ranged from 0.062 to 211.32 μg/L and the detection capability from 0.080 to 233.71 μg/L. Average recoveries of the analytes spiked in raw milk were in the range of 70.83% to 109%, intra-day coefficient of variation (CV) values from 2.41% to 22.29%, and inter-day CV values from 3.48% to 23.91%. The method was successfully applied in the testing of bovine milk samples. In five samples residues were detected. They were sulfadimethoxine (in two samples), enrofloxacin, tetracycline and oxytetracycline and were at concentrations below the EU maximum residue limit. The method is useful for routine testing for this group of chemical hazards in bovine milk.

Multi-class and multi-residue analyses are very complex procedures because of the physico-chemical properties of veterinary drug residues and other contaminants. The purpose of the study was to develop an analytical method for the sensitive determination of 69 analytes in bovine milk by liquid chromatography electrospray ionisation–tandem mass spectrometry.

Medicinal products in Europe are under the strict control of many organisations headed by the European Directorate for the Quality of Medicines and HealthCare (EDQM) in Strasbourg and its related General European Official Medicines Control Laboratories (OMCLs) Network (GEON). The EDQM works in cooperation with the European Medicines Agency (EMA) and the World Health Organisation (WHO). All of these institutions have one main goal – to protect public health in Europe and around the world. One of the more important effects of the harmonisation of pharmaceutical law in Europe was the introduction of the mutual recognition principle for the Official Control Authority Batch Release (OCABR)/Official Batch Protocol Review (OBPR) certificates in the European Union. The National Veterinary Research Institute (NVRI) in Poland is an example of an OMCL laboratory within the Veterinary Batch Release Network (VBRN) that issues the European certificates. The NVRI is actively involved in the batch release of immunological veterinary medicinal products (IVMPs), with approximately 1,800 certificates for IVMPs issued per year. It is also one of only four veterinary OMCLs that perform Post Marketing Surveillance (PMS) studies including approximately 47 IVMPs per year. All the results of the testing data are sent to the Chief Veterinary Officer, and also to the electronic Network platforms of the EDQM, which enables transparent information exchange.

Medicinal products in Europe are under the strict control of many organisations headed by the European Directorate for the Quality of Medicines and HealthCare (EDQM) in Strasbourg and its related General European Official Medicines Control Laboratories (OMCLs) Network (GEON). The EDQM works in cooperation with the European Medicines Agency (EMA) and the World Health Organisation (WHO). All of these institutions have one main goal – to protect public health in Europe and around the world. One of the more important effects of the harmonisation of pharmaceutical law in Europe was the introduction of the mutual recognition principle for the Official Control Authority Batch Release (OCABR)/Official Batch Protocol Review (OBPR) certificates in the European Union. The National Veterinary Research Institute (NVRI) in Poland is an example of an OMCL laboratory within the Veterinary Batch Release Network (VBRN) that issues the European certificates. The NVRI is actively involved in the batch release of immunological veterinary medicinal products (IVMPs), with approximately 1,800 certificates for IVMPs issued per year. It is also one of only four veterinary OMCLs that perform Post Marketing Surveillance (PMS) studies including approximately 47 IVMPs per year. All the results of the testing data are sent to the Chief Veterinary Officer, and also to the electronic Network platforms of the EDQM, which enables transparent information exchange.

Introduction: There are many veterinary products containing β-lactam antibiotics which are used for mastitis treatment in cows. The aim of the study was to determine whether mastitis could have any effect on amoxicillin (AMX) or penicillin G procaine (PEN) withdrawal period from milk, in the context of current maximum residue limits established by the European Commission. Material and Methods: The study was conducted on 17 dairy Black and White cows with clinical mastitis during the lactation period. The first group (n = 8) received 200 mg of amoxicillin (AMX), whereas the second group (n = 9) received 200,000 IU/mg of penicillin G procaine (PEN) by intramammary administration. For the measurement of AMX and PEN concentrations in milk, the liquid chromatography tandem mass spectrometry method was applied. Pharmacokinetic calculations were performed using Phoenix WinNonlin 6.4 software. Results: The determined AMX and PEN half-life values in the mammary gland suggest that the drug withdrawal is at a level of 99.9% within 81 h (≈3.5 days) and 116 h (≈5 days) after administration of AMX and PEN, respectively. The present research indicates that, at 60 h after administration, the average PEN concentration in the milk from cows with clinical signs of mastitis may still reach 4.96 g/kg and that of AMX can even be 6.92 g/kg. Conclusion: The results obtained confirm that, in mastitis cases, a 72-h withdrawal period is sufficient for elimination of AMX to a lower level than the established maximum residue limit (MRL) values. However, in the case of PEN, at 69 h after administration, the drug concentration may be close to that of the determined MRL.

Introduction: There are many veterinary products containing β-lactam antibiotics which are used for mastitis treatment in cows. The aim of the study was to determine whether mastitis could have any effect on amoxicillin (AMX) or penicillin G procaine (PEN) withdrawal period from milk, in the context of current maximum residue limits established by the European Commission.