ABSTRACT
OBJECTIVE: To develop an LC-MS/MS method for the determination of vonoprazan pyroglutamate and vonoprazan fumarate in rat urine to determince the urine excretion of the two drugs in SD rats. METHODS: The detection was performed on an API 4000 tandem mass spectrometer equipped with an electrospray ionization (ESI) source. Multiple reaction monitoring (MRM) was selected with the transitions of m/z 346.2 to 315.2 for TAK-438 P and m/z 237.2 to 194 for IS, respectively. Separation of the analytes was achieved by a Shimadzu liquid chromatography system with an Agelient C18 analytical column (4.6 mm×150 mm, 3.5 μm). Isocratic elution was adopted with mobile phase A (10 mmol•L-1 ammonium acetate and 0.1% formic acid) and mobile phase B (methanol) at the ratio of 40:60, at a flow rate of 0.6 mL•min-1. The total run time was 6 min and the injected sample volume was 5 μL. All the features of the developed method suggested it met the criteria for bioanalytical METHODS recommended by regulatory authorities. The accumulative urine excretion rates of TAK-438 F and TAK-438 P were determined after oral administration of TAK-438 P and equimolar TAK-438 F in SD rats. RESULTS: The accumulative urine excretion rates of the prototype drugs were 2.11% and 2.03%, respectively. The low excretion rates indicated that metabolism might be the major clearance mechanism of TAK-438 P and TAK-438 F. CONCLUSION: This was the first time to establish and validate a simple, rapid and sensitive LC-MS/MS method for the quantification of TAK-438 P. There is no significant difference of the accumulative urine excretion rate between TAK-438 P and TAK-438 F in SD rats, which provides the basis for the druggability of TAK-438 P.