LC-ESI-MS Method for the Determination of Mizolastine in Human Plasma

A sensitive and rapid liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method has been developed and validated for the determination of mizolastine in human plasma using dipyridamole as the internal standard (I.S.). Plasma samples were simply pretreated with methanol for deproteinization. Chromatographic separation was performed on an Agilent Zorbax C₁₈ column with a mobile phase of 10 mM ammonium acetate buffer containing 0.1% formic acid–methanol (20:80, v/v) at a flow rate of 1 mL min⁻¹. The electrospray ionization (ESI) interface was employed in a single quadrupole mass spectrometer. The analytes were protonated in the positive ESI interface and detected in single ion monitoring (SIM) mode. Chromatographic separation was achieved in less than 3.5 min. The linearity was established over the range of 0.5–600 ng mL⁻¹. The lower limited of quantification (LLOQ) of the method was 0.5 ng mL⁻¹. The intra- and inter-run standard deviations were both less than 11.2%. The method was applied to study the pharmacokinetics of the mizolastine sustained-release tablets in healthy volunteers.