Determination of antazoline hydrochloride in rat plasma and excreta by reversed-phase ion-pair chromatography and its application to pharmacokinetics.

A reversed-phase ion pair chromatography method with liquid-liquid extraction analytical method was developed and validated for the determination of antazoline hydrochloride in plasma and excreta of rat. The aim of our study was to characterize the preclinical pharmacokinetics and excretion profiles of antazoline hydrochloride in rats after intravenous injection at the dose of 10 mg/kg. Plasma and excreta samples were extracted with ethyl acetate, and phenacetin was used as the internal standard. The result showed that the method is suitable for the quantification of antazoline hydrochloride in plasma and excreta samples. Analysis of accuracy (90.89-112.33%), imprecision (<7.1%) and recovery (>82.5%) showed adequate values. After a single intravenous administration at 10 mg/kg to rats, plasma concentration profile showed a relative fast elimination proceeding with a terminal elimination half-life of 3.53 h. Approximately 61.8 and 14.2% of the administered dose were recovered in urine and bile after 72 and 24 h post-dosing respectively; 5.9% of the administered dose was recovered in feces after 72 h post-dosing. The above results show that the major elimination route is urinary excretion.

Determination of antazoline hydrochloride in Beagle dog plasma by HPLC-UV and its application to pharmacokinetics.

In order to evaluate the pharmacokinetics characteristic of antazoline hydrochloride in Beagle dogs, a sensitive and specific HPLC method was developed and validated using phenacetin as the internal standard (IS). The analyte and the IS were extracted from dog plasma by ethyl acetate under the basic condition. The analyte was separated by a C18 column and detected with a variable wavelength UV-detector. The mobile phase consisted of methanol-5mmolL(-1) tetrabutyl ammonium bromide (45:55, v/v) containing 0.5% glacial acetic acid in a flow rate of 1.0mLmin(-1). Standard calibration graph for antazoline was linear over a curve range of 20-1600ngmL(-1) (R>0.99) and the lower limit of quantification was 20ngmL(-1) using a plasma sample of 500µL. The intra- and inter-day precision values were less than 14.3% relative standard deviation (RSD). The intra-day assay accuracy was in the range of 98.1-100.6% and the inter-day assay accuracy in the range of 99.2-101.1%. The extraction recoveries were on the average of 88.4% for antazoline and 76.8% for IS. Plasma samples were stable at least for 1 month at -20°C. This method was successfully applied to pharmacokinetics study of antazoline after intravenous administration to Beagle dogs.