The Thermodynamic Overlapping pKa of the Antitumor Drug Ibrutinib Using Multiwavelength UV/VIS-Spectroscopy and Potentiometry

Ibrutinib (USAN, also known as PCI-32765 and marketed under the name Imbruvica) (Figure 1) of formula C25H24N6O2 and molar mass 440.497 is an anticancer drug targeting B-cell malignancies. It was approved by the US Food and Drug Administration (FDA) in November 2013 for the treatment of mantle cell lymphoma and in February 2014 for the treatment of chronic lymphocytic leukemia. Ibrutinib is currently under development by Pharmacyclics, Inc and Johnson & Johnson’s Janssen Pharmaceutical division for additional B-cell malignancies including diffuse large B-cell lymphoma and multiple myeloma [1,2]. In January 2015, Ibrutinib was approved by the FDA for treatment of Waldenström’s macroglobulinemia, a form of non-Hogkin ́s lymphoma.