Simultaneous Determination of Two Tyrosine Kinase Inhibitors in Tablets by HPLC-MS analysis

The class of tyrosine kinase inhibitors (TKIs) is represented by a group of compounds which are currently used in the treatment of different types of cancer. These oral medicines present a narrow therapeutic index and a large inter-and intra-individual variability. Within this work, a simple, accurate and rapid reversed phase ultra-high-performance liquid chromatographic (RP-UHPLC) method with mass spectrometric (MS) detection for simultaneous analysis of two TKIs, ibrutinib and ruxolitinib, using pentoxifylline as internal standard (IS) in tablet dosage forms is presented. The separation was carried out on a Waters (Milford, Massachusetts, USA) Arc System coupled with a Waters QDa mass detector. The column used was a Waters CORTECS C18 (4.6×50mm, 2.7μm); a gradient elution was carried out using a mixture of ammonium formate 10 mM aqueous solution and acetonitrile. The flow rate of the mobile phase was set to 0.5mL/min. The column temperature was equilibrated to 40°C. The injected volume was 5μL. All samples were kept at 20°C during the entire analysis. Mass spectra were recorded in positive ionization mode in the range of m/z 100-400 for ruxolitinib and m/z 100-500 for ibrutinib. Quantification was established in single ion recording (SIR) mode for each compound, using pentoxifylline as internal standard. The method was validated according to International Guidelines in terms of stability, limit of detection, limit of quantitation, linearity, precision and accuracy. The validated method can be successfully applied for simultaneous determination of TKIs in tablet dosage forms.