Development of LC-MS/MS Method for Determination of Iloperidone in Rabbit Plasma: Application to a Pharmacokinetic Study

Abstract

Objectives: Estimation of drug in plasma during in vivo studies requires a highly sensitive and precise method. Thus, the objective of the current study is to develop a LC-MS/MS method for quantitation of Iloperidone (ILO) in rabbit plasma, which was further used for in vivo study as a part of development of long acting depot formulation.

Methods: The quantitation of the drug was determined by positive ion mode with multiple reaction monitoring (MRM). Plasma extraction was carried out using Celerity Deluxe cartridge showing more than 95 % recovery. The chromatographic conditions for quantitation of ILO were use of Kromasil C18 (50*4.6 mm, 5 µm) column using, 0.01M Ammonium format Buffer (pH 5.5): Acetonitrile (10:90) as mobile phase. Olanzapine was used as an internal standard. The developed method was applied for pharmacokinetics study of ILO in rabbits after intramuscular administration of 6.24 mg/kg dose.

Results: The method was linear over concentration range of 0.5-100 ng/ml with correlation coefficient more than 0.999. The lower limit of quantitation was 0.5 ng/ml and recovery was found more than 95% for ILO and olanzapine. Extraction and estimation of ILO were performed using the developed method. Steady release of ILO from depot formulation was observed up to 14 days in rabbits.

Conclusion: The developed LC-MS/MS method was precise and having detectability for lower drug concentration in rabbit plasma and it was successfully applied to study in vivo drug release in rabbits.