Faculty of Food Technology and Biotechnology, University of Zagreb
Abstract
The aim of the study is to evaluate the suitability of plasma and urine as matrices for clenbuterol residue determination during and after its subchronic administration at a growth-promoting dose to male pigs, using previously validated enzyme-linked immunosorbent assay (ELISA) as a screening method and liquid chromatography tandem mass spectrometry (LC-MS/MS) as a confirmation method. A high correlation coefficient between these analytical methods was obtained for both urine (R=0.9800) and plasma (R=0.9970) concentrations. Study results show the plasma and urine concentration to vary greatly during oral treatment with clenbuterol for 28 days. The peak urine concentration ((88.54±50.54) ng/mL) recorded on day 21 was 40-fold peak plasma concentration ((2.25±1.54) ng/mL). After withdrawal period, the peak urine clenbuterol concentration ((42.93±10.52) ng/mL) recorded on day 0 was 24-fold plasma concentration ((1.79±0.97) ng/mL). The maximum allowed concentration of 0.5 ng/g in the liver as a regulated matrix for control of clenbuterol abuse was achieved in plasma on day 3 ((0.52±0.26) ng/mL) and in urine on day 7 of treatment withdrawal ((0.45±0.11) ng/mL). Study results indicate that urine and plasma may be suitable matrices for the control of clenbuterol abuse during fattening of food-producing pigs but have a limited value because of the rapidly decreasing concentration upon treatment withdrawal, in plasma in particular.Svrha je rada utvrditi prikladnost plazme i urina kao matriksa za određivanje ostataka klenbuterola tijekom i nakon subkroničnog davanja doze koja potiče rast muških svinja, primjenom prethodno validirane metode: ELISA kao screening metodu i tekućinsku kromatografiju s masenom spektrometrijom (LC-MS/MS) kao potvrdnu metodu. Primijenjenim analitičkim metodama određen je visoki korelacijski koeficijent u urinu (R=0,9800) i plazmi (R=0,9970). Rezultati istraživanja pokazali su da se koncentracije klenbuterola u plazmi i urinu značajno razlikuju tijekom 28 dana oralne primjene klenbuterola. Najveća koncentracija u urinu ((88,54±50,54) ng/mL), određena 21. dan, bila je 40 puta veća od najveće koncentracije određene u plazmi ((2,25±1,54) ng/mL). Nakon prestanka obrade, najveća koncentracija klenbuterola u urinu ((42,93±10,52) ng/mL) određena je 0. dan i bila je 24 puta veća od one određene u plazmi ((1,79±0,97) ng/mL). Maksimalno dopuštena koncentracija od 0,5 ng/g u jetri, kao regulatornom matriksu što se koristi u kontroli zlouporabe klenbuterola, u plazmi je određena 3. dan ((0.52±0.26) ng/mL), a u urinu 7. dan ((0,45±0,11) ng/mL) nakon tretmana. Rezultati istraživanja pokazuju da urin i plazma mogu biti prikladni matriksi u kontroli zlouporabe klenbuterola tijekom tova svinja, ali s ograničenom primjenom zbog naglog opadanja koncentracije nakon prestanka tretmana, a posebno u plazmi
