High performance liquid chromatography with ultraviolet detection for the determination of SYUIQ-5, a novel telomerase inhibitor for cancer therapy: Application to an enzyme kinetic study in rat liver microsomes

A sensitive assay for the determination of SYUIQ-5, a novel telomerase inhibitor and anti-tumor drug, in rat liver microsomes was developed by using high-performance liquid chromatography with ultraviolet detection. SYUIQ-5 was incubated in vitro with liver microsomes from rats pretreated with control vehicle, beta-naphthofIavone, phenobarbital, 20% ethanol or dexamethasone. The analytes were extracted with diethyl ether and separated a C-18 5-mu m analytical column. Elution was conducted with 30 mM[ dipotassium hydrogen phosphate (pH 8.0)-methanol-triethylamine (30:70:0.05, v/v/v) at a flow-rate of 1.0 ml/min and the detection of UV absorbance was conducted at 278 nm. Intra-day and inter-day precision and accuracy of the method were within 10%. The mean analytical recoveries of SYUIQ-5 ranged from 78.8 to 95.3%. The linearity of the calibration curve was in the range of 1.0-80.0 mu M. The lower limit of quantification (LOQ) was 1.0 mu M. Kinetic analysis showed that beta-naphthoflavone and dexamethasone significantly induced SYUIQ-5 metabolism, suggesting that cytochrome P450 1 and 3A are the major contributor to SYUIQ-5 metabolism in rat liver microsomes.