Drug Interaction Potential of Berberine Hydrochloride When Co-Administered with Tofacitinib and Filgotinib in Rats

The co-treatment of ulcerative colitis with berberine hydrochloride (BBR), the Janus kinase(JAK) inhibitor Tofacitinib (TOFA), and Fligotinib (FIGA) is feasible and sophisticated in terms of mechanism. However, no studies have yet explored their interactions. This study aimed to establish a highly sensitive, specific, and reproducible HPLC-MS/MS method for investigating the pharmacokinetic interactions between BBR-TOFA and BBR-FIGA in rats.

The analytes and internal standards were extracted from rat plasma using a mixed solvent of dichloromethane and ether (3:2 ratio). The mobile phase comprised a mixture of methanol (containing 0.1% formic acid) and water (containing 0.1% formic acid and 2 mm ammonium acetate), with a flow rate of 0.6 mL/min. Elution was performed in a gradient mode on a Phenomenex Kinetex column (50×3.0 mm, 2.6 μm). A systematic methodological validation was conducted according to the standards of the Chinese Pharmacopoeia, covering aspects such as specificity, calibration curve and linearity, residual effects, precision and accuracy, recovery, matrix effect, dilution integrity, and stability.

All methodological validation parameters met the standards of the Chinese Pharmacopoeia, confirming the method's suitability for simultaneously determining the concentrations of BBR, TOFA, and FIGA in rat plasma. Pharmacokinetic experimental results indicate that TOFA and FIGA have no significant effect on the plasma concentration of BBR across various pharmacokinetic parameters. However, due to BBR's inhibition or induction of various drug-metabolizing enzymes, it significantly affects some of the pharmacokinetic parameters of TOFA and FIGA.