Background: Ursodeoxycholic Acid (UDCA), also known as Ursodiol, is a secondary bile acid (BA), with therapeutic applications. UDCA is standard therapy for cholestatic hepatopathies in humans. In recent years, its use has been increasingly explored in equine medicine for similar indications. Pharmacokinetic data for UDCA in horses are currently lacking. Hypothesis/
Objectives: To describe the pharmacokinetics parameters following a single intra-gastric administration of 15 mg/kg in healthy, fasted horses and to characterize the changes in their BA profiles. Animals: Nine healthy mares from Cornell research herd.
Methods: Horses were administered a single dose 15 mg/kg of UDCA intra-gastrically. Plasma concentrations of UDCA and 19 additional bile acids were measured over 72 hours using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pharmacokinetic data were analyzed by a non-compartmental model.
Results: Plasma concentrations increased rapidly, with peak concentrations (Tmax; mean ± S.D) occurring at 2.44 ± 1.3 hours. Plasma levels decreased significantly in most horses by 24 hours, with negligible concentrations detected at 72 hours. Half-life was calculated at 7.99 ± 2.25 hours and the dose interval estimated at 24.29 hours. Pharmacokinetic profile of taurine conjugated UDCA also supports a dose interval of 24 hours. Complete BA profiles indicate transient depression of primary BA and enhancement of secondary BA following UDCA administration. Conclusions and Clinical Importance: The oral dose of 15 mg/kg every 24 hours is appropriate for adult horses. Clinicians should be aware that total BA concentrations will increase and remain elevated for up to 24 hours post-administration of UDCA.
Learning Objectives:
know pharmacokinetics of Ursodiol in adult horses
define Bile Acids profile changes when Ursdodiol is administered
