In Vivo Administration of Stanozolol in Cattle: Depletion and Stability Studies Using UHPLC-Q-Orbitrap

Abstract

An in vivo study was performed in order to evaluate the depletion time of stanozolol and its main metabolites using naturally incurred urine sample collected after the administration of intramuscular injections in 12 steers. A stability study was also carried out to investigate the influence of the storage period and the freeze−thaw cycles. A fast parent drug metabolization was observed, because within 6 h after drug administration, the signal of the metabolite 16β-hydroxystanozolol was predominant. After the second drug administration, a detection window of 17 days was obtained. The stability was studied using ANOVA, in which a storage condition of −20 °C proved stable during 240 days, which was also confirmed after 5 freeze−thaw cycles.

Multiresidue Determination of Growth Promoters in Bovine Serum using QuEChERS and UHPLC-Q-ORBITRAP: Validation and In Vivo Study

“…In a previous in vivo study developed by our group using bovine urine, some differences were observed when comparing both matrices . As for urine, STN was only detected at D0 + 6 h, whereas in serum, this analyte was detected between 3 and 10 days (inter-animal variation was observed).…”

“…It should be highlighted that 16OHSTN was only detected at D0 + 6 h, D1, D7 + 6 h, and D8, i.e., shortly after drug administration. In this way, this compound should not be set as the main marker residue for STN treatment for the serum matrix, which is suggested for urine. − Therefore, the parent drug compound itself, STN, should be monitored as the marker for this treatment when using serum.…”

“…Buiarelli et al (2004) have not detected the parent compound STN, although the metabolites 16OHSTN, 4β-hydroxystanozolol (4OHSTN), and 3β-hydroxystanozolol (3OHSTN) were observed in bovine urine, in which 16OHSTN was detected in greater concentration values . Silva et al (2022) obtained a detection window of 17 days for bovine urine in which the intensity of 16OHSTN was predominant over the other metabolites . It should be highlighted that 16OHSTN has been defined as the marker residue of STN in urine, muscle, and liver .…”

“…30 Silva et al (2022) obtained a detection window of 17 days for bovine urine in which the intensity of 16OHSTN was predominant over the other metabolites. 31 It should be highlighted that 16OHSTN has been defined as the marker residue of STN in urine, muscle, and liver. 32 The authors have not found any work that presented in vivo studies covering STN in bovine serum.…”