Pharmacokinetics of altrenogest in horses.
The Federation Equestre Internationale has permitted the use of altrenogest in mares for the control of oestrus. However, altrenogest is also suspicious to misuse in competition horses for its potential anabolic effects and suppression of typical male behaviour, and thus is a controlled drug. To investigate the pharmacokinetics of altrenogest in horses we conducted an elimination study. Five oral doses of 44 mug/kg altrenogest were administered to 10 horses at a dose interval of 24 h. Following administration blood and urine samples were collected at appropriate intervals. Altrenogest concentrations were measured by liquid chromatography-tandem mass spectrometry. The plasma levels of altrenogest reached maximal concentrations of 23-75 ng/mL. Baseline values were achieved within 3 days after the final administration. Urine peak concentrations of total altrenogest ranged from 823 to 3895 ng/mL. Twelve days after the final administration concentrations were below the limit of detection (ca 2 ng/mL).
Machnik
M
M
Institute of Biochemistry, German Sport University, Cologne, Germany. m.machnik@biochem.dshs-koeln.de
Hegger
I
I
Kietzmann
M
M
Thevis
M
M
Guddat
S
S
Schänzer
W
W
D000284:Administration, Oral; D000818:Animals; D002853:Chromatography, Liquid / Q000662:veterinary; D004300:Doping in Sports / Q000517:prevention & control; D006736:Horses / Q000378:metabolism*; D008297:Male; D013058:Mass Spectrometry / Q000662:veterinary; D045167:Progesterone Congeners / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D015203:Reproducibility of Results; D015813:Substance Abuse Detection / Q000662:veterinary; D014204:Trenbolone Acetate / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine
D045167:Progesterone Congeners; C023445:altrenogest; D014204:Trenbolone Acetate