Development and validation for the determination of olopatadine in human plasma by liquid chromatography–tandem mass spectrometry: application to a bioequivalence study of Ilhwa Allotadine tablet (olopatadine HCl 5 mg)

A sensitive and specific method based on liquid chromatographic–tandem mass spectrometric method (LC–MS/MS) has been developed and validated to determine plasma concentrations of olopatadine. Olopatadine and internal standard (IS, loratadine) from human plasma were extracted using solid-phase extraction. Chromatographic separation was achieved on a reversed-phase Capcellpak CR column using the isocratic mobile phase consisted of 70 % acetonitrile and 30 % water containing 10 mM ammonium acetate (adjusted to pH 4.0 with acetic acid). Acquisition was performed in multiple reaction monitoring mode by monitoring the transitions: m / z 337.92 → 164.80 for olopatadine and m / z 383.17 → 336.90 for IS. This method was fully validated. The calibration curve was linear over the concentration range from 0.2 to 100 ng/mL, and correlation coefficients ( r 2 ) were greater than 0.99. The low limit of quantitation with a relative standard deviation below 20 % was 0.2 ng/mL. The intraday and interday precisions ranged 6.31–16.80 % and intraday and interday accuracies ranged 91.17–110.08 %. The devised method was successfully applied in a bioequivalence study of two formulations of olopatadine, Allotadine tablet and Allelock tablet in 26 healthy Korean volunteers following single oral administration.