1Advanced Diagnostics and Therapeutics Institute, Health Sector, King Abdulaziz City for Science and Technology (KACST), P.O. Box 6086, Riyadh, 11442, Saudi Arabia
2Racing Forensic Laboratory, Royal Court Affairs, Alfelaj, Muscat, Oman
3Abu Dhabi Forensic Evidence Department, Abu Dhabi GHQ, Abu Dhabi, UAE
The pharmacokinetics and pharmacodynamics of a betamethasone (formulation dipropionate and sodium phosphate) were evaluated in 4 healthy camels after a single intramuscular dose of 35 µg/kg body weight. A sensitive, validated LC-MS/MS method for the quantification of plasma betamethasone and hydrocortisone was developed. Plasma betamethasone versus time concentration was best described by a two-compartment open model. The pharmacokinetic parameters median and range were as follows: terminal elimination half-life was 7.17 (6.93-7.58) h, Cmax was 15.9 (10.8-20.85) ng/ml, and Tmax was 0.5 (0.25-0.75) h. The estimated IC50 for hydrocortisone (mean ± SD) was 0.09 ± 0.08 ng/ml. Based on the analytical method and plasma terminal elimination half-life, a 4-day withdrawal period of the betamethasone formulation is advised prior to racing.
Betamethasone, Camels, Pharmacokinetics, Pharmacodynamics
