A validated LC-MS/MS method for the determination of tolterodine and its metabolite in rat plasma and application to pharmacokinetic study.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used for simultaneous quantification of tolterodine and its metabolite 5-hydroxy methyl tolterodine in rat plasma. Tolterodine-d6 and 5-hydroxy methyl tolterodine-d14 were used as internal standards (IS). Chromatographic separation was performed on Ascentis Express RP amide (50 mm×4.6 mm, 2.7 μm) column with an isocratic mobile phase composed of 10 mM ammonium acetate and acetonitrile in the ratio of 20:80 (v/v), at a flow-rate of 0.5 mL/min. Tolterodine, tolterodine-d6, 5-hydroxy methyl tolterodine and 5-hydroxy methyl tolterodine-d14 were detected with proton adducts at