Pharmacokinetics of Intravenously Administration of Prednisolone in the Horse as Determined by Radioimmunoassay

C. L. Chen ； J. Goldberg ； R. R. Gronwall

《The Chinese Journal of Physiology》 38卷1期 (1995/03) Pp. 1-6

並列摘要

A radioimmunoassay was developed for prednisolone using IgG purified from rabbit antiserum. The assay was employed to determine the pharmacokinetics of prednisolone following intravenous administration of 450mg of prednisolone sodium succinate (Solu Delta Cortef) to five adult Thoroughbred horses. The RIA had a sensitivity of 2 ng/ml and was relatively specific. It had cross-reactivity with 21- deoxycortisol (83.3%) cortisol (27.8%), 11- 3-hydroxyprogesterone (39.2%) and 17-hydroxyprogesterone (50%). However, it did not cross-react with naturally occurring steroids (cholesterol, testosterone, estradiol or progesterone) or synthetic steroids (betamethasone, methylprednisolone, prednisone or triamcinolone). Radioimmunoassay of the horse serum samples detected the presence of prednisolone for 5 to 7 hours post administration. The pharmacokinetic parameters tested and their means were a half-life of 1.150±0.233 (±SEM) hours, an excretion constant of 0.686 ±0.018 Ke/hr, a volume of distribution of 607 ±109 ml/kg, and a clearance rate of 374 ±47 ml/hr/kg. RIA also detected the presence of prednisolone in the urine beginning one hour post administration. The prednisolone in the urine increased significantly at 2 hours and reached a peak at 4 hours post administration. The urinary levels decreased at 5, 6, and 7 hours and peaked again at 8 hours. The level then gradually decreased and reached the minimal detectable levels in 48 hours. These results showed that the RIA was sensitive and relatively specific for the determination of prednisolone. Administration of prednisolone resulted in detectable levels of prednisolone in serum for up to 7 hours and in detectable level in urine up to 48 hours following post intravenous injection.

並列關鍵字

Prednisolone ； Clearance ； RIA ； horse