A Fast Immunoassay for Determination of β-Agonist Residues in Plasma

Abstract

Plasma residues of β-agonists during and after oral administration of subchronic anabolic doses of clenbuterol and salbutamol in mice were determined by use of the enzyme-linked immunosorbent assay (ELISA) as analytical method. The reliability of ELISA as a screening method for quantitative determination of clenbuterol and salbutamol plasma residues was tested by assay validation. Plasma usefulness as a matrix in the control of anabolic abuse was tested by determination of clenbuterol and salbutamol plasma residues. On day 28 of anabolic treatment, the peak plasma clenbuterol concentration was 10.75±2.45 ng/mL and 13.57±3.21 ng/mL in white and black mice, respectively, which was a fourfold peak salbutamol concentration (2.50±0.15 ng/mL and 3.66±0.22 ng/mL, respectively). On day 5 of treatment discontinuation, the levels of clenbuterol and salbutamol residues were below the analytical method limit of detection. Results of the method validation showed ELISA to be applicable in quantitative (ng/mL) determination of β-agonist residues in plasma. Study results also indicated plasma to be a suitable matrix in the control of β-agonist abuse ; however, only as a second choice matrix during fattening because of the very short time of the residues being detectable after treatment discontinuation. Therefore, in comparison with other potential matrices (urine and hair), plasma is of a limited value in the control of β-agonist abuse in live animals.