Validation of a sensitive and automated 96-well solid-phase extraction liquid chromatography–tandem mass spectrometry method for the determination of desloratadine and 3-hydroxydesloratadine in human plasma

To support clinical development, a liquid chromatographic–tandem mass spectrometric (LC–MS–MS) method was developed and validated for the determination of desloratadine (descarboethoxyloratadine) and 3-OH desloratadine (3-hydroxydescarboethoxyloratadine) concentrations in human plasma. The method consisted of automated 96-well solid-phase extraction for sample preparation and liquid chromatography/turbo ionspray tandem mass spectrometry for analysis. [2H4]Desloratadine and [2H4]3-OH desloratadine were used as internal standards (I.S.). A quadratic regression (weighted 1/concentration2) gave the best fit for calibration curves over the concentration range of 25–10 000 pg/ml for both desloratadine and 3-OH desloratadine. There was no interference from endogenous components in the blank plasma tested. The accuracy (%bias) at the lower limit of quantitation (LLOQ) was −12.8 and +3.4% for desloratadine and 3-OH desloratadine, respectively. The precision (%CV) for samples at the LLOQ was 15.1 and 10.9% for desloratadine and 3-OH desloratadine, respectively. For quality control samples at 75, 1000 and 7500 pg/ml, the between run %CV was ≤7.5% for desloratadine and ≤6.3% for 3-OH desloratadine. Between run %bias ranged from 4.1 to 8.0% for desloratadine and −11.5 to −4.8% for 3-OH desloratadine. Desloratadine and 3-OH desloratadine were stable in human plasma for 401 days at −22 °C, after five freeze/thaw cycles, up to 24 h at room temperature, and in reconstituted sample extracts (up to 185 h at 5 °C). This LC–MS–MS method for the determination of desloratadine and 3-OH desloratadine in human plasma met regulatory requirements for selectivity, sensitivity, goodness of fit, precision, accuracy and stability.