Development of UHPLC‐MS/MS Method for Evaluation of the Acute Oral Toxicity and Pharmacokinetics of Ursodeoxycholic Acid and Silymarin Combination in Rats

Abstract

The combination of ursodeoxycholic acid (UDCA) and silymarin has been shown to alleviate various hepatic conditions. This study aimed to evaluate the acute oral toxicity and in vivo pharmacokinetics of the combination in female Sprague Dawley rats. The acute oral toxicity and the pharmacokinetic studies were conducted using 17 rats divided into five groups and 30 rats assigned into four control groups and one treatment group, respectively. A new UHPLC/MS‐MS method was applied to determine silibinin (SIL) and UDCA in plasma, urine, and feces. This method used the BEH C8 column (1.7 µm, 100 × 2.1 mm) with a gradient elution of 0.01% formic acid in water and 0.01% formic acid in acetonitrile. The acute oral toxicity study revealed that administering the combination at 5000 mg/kg preserves a wide safety margin. In the pharmacokinetic study, the combination resulted in a significant enhancement of the absorption of both drugs and a reduction of the renal elimination of silymarin. The oral LD50 of the combination was higher than 5000 mg/kg, so according to the OECD guidelines, it was classified in Category 5 GHS. The presented data serve as scientifically defensible safety data with a defined absorption and elimination profile for the combination.