HPLC methods for studying pharmacokinetics of tivozanib and in vitro metabolic interaction with dexamethasone in rat

Tivozanib is a recently approved tyrosine kinase inhibitor for the treatment of renal cell carcinoma. In this work, two new HPLC methods coupled with fluorescence (FLD), or photodiode array detectors (PDA) were developed and used for the first time for tivozanib quantification in rat plasma and liver microsomes. The described methods were efficient with a 4-min runtime employing a Gemini-NX C₁₈ column (50 × 2.1 mm, 3 µm) and a mobile phase of acetonitrile and ammonium acetate buffer (pH 4.7, 10 mM) (40:60, v/v) delivered at a flow rate of 0.4 mL/min. The use of HPLC-FLD allowed the quantification of 50 ng/ mL tivozanib using only 100 µL rat plasma. The HPLC-FLD method was validated according to the US food and drug administration (FDA) bioanalytical guidelines and was applied successfully in a rat pharmacokinetic study (n = 7) following oral administration of 1 mg/ kg tivozanib. Furthermore, HPLC-PDA was used for monitoring the depletion of 1 μM (454.9 ng/mL) tivozanib in rat liver microsomes and was applied to study the effect of dexamethasone induction on tivozanib metabolism in vitro. Results showed that dexamethasone enhanced the intrinsic clearance of tivozanib by 60 % suggesting a potential drug-drug interaction at the metabolism level. Dexamethasone is commonly used in the management of cancer disease and thus coadministration with tivozanib therapy may cause treatment failure in patients. The simplicity, speed and cost-effectiveness of the reported methods are ideal for supporting in vivo and in vitro tivozanib studies, including drug-drug interaction studies, particularly in bioanalytical labs lacking LC-MS/MS capabilities.