Development and Validation of an RP-HPLC-UV Method for the Determination of Ondansetron in Rabbit Plasma: Application to a Pharmacokinetic Study

A new sensitive and specific isocratic RP-HPLC-UV method was developed and validated for the determination of ondansetron in rabbit plasma using risperidone as an internal standard (IS). The sample preparation involved a simple deprotenization procedure with a mixture of 1 mL of acetonitrile and 50 mu L of 10% w/v zinc sulfate. Analysis was performed on a Phenomenex CN column (250 mm x 4.6 mm, 5 mu m) with 50 mM ammonium acetate (pH 3.5) and acetonitrile (35: 65, v/v) as mobile phase at a flow rate of 1.0 mL min(-1). Column eluent was monitored at 310 nm. The calibration curve was linear over the concentration range of 25-1000 ng mL(-1) (r(2) = 0.9999) with a limit of quantification (LOQ) 25 ng mL(-1). The intraday and interday precision and accuracy were between 0.93% and 3.41% and -3.63% and 1.01%, respectively. The mean recoveries of ondansetron and risperidone were 85.87% and 99.80%, respectively. Ondansetron-containing plasma samples were stable at -20 degrees C for 14 days. The validated method was successfully applied for a pharmacokinetic study after a single oral administration of ondansetron (8 mg) to rabbits.