Supported liquid extraction and LC-MS-MS determination of iloperidone and olanzapine in rat plasma: Application to a...

A sensitive, selective rapid bioanalytical assay method was developed and quantification of iloperidone (ILP) and olanzapine (OLZ) in rat plasma was done by mass spectrometry. Systematic sample preparation and extraction procedure were carried out by supported liquid extraction using dichloromethane to extract both the eluents (ILP and OLZ) from rat plasma samples. The extorted samples were injected on a selective Waters XTerra® C18 reverse-phase bonded column (250 × 4.6 mm i.d., 5 μm) using acetonitrile and 15 mM ammonium formate containing 0.05% trifluoroacetic acid (60:40 v/v) for isocratic elution mode and detected by mass spectrometry. Calibration curves were drawn with the respective assay statistical data and showed linear regression coefficients greater than 0.9996 over the concentration ranges 2-5,000 ng/mL for ILP and OLZ, respectively. The absolute mean recoveries were found to be in the replicate range of 87.12-94.47%, respectively. The obtained results by the method revealed good intra and interday assay performance in terms of 1.70-5.90% precision and 0-5% accuracy. The validated bioassay method has been successfully applied to the pharmacokinetics in rats.