A Rapid Quantitative Analysis of the β-Blocker Timolol in Human Urine by HPLC-Electrochemical Detection

Abstract

Abstract A High Performance Liquid Chromatographic method with amperometric detection has been developed for the determination of the β-blocker 1-[(1, 1-dimethylethyl) amino]-3-[[4-(4-morpholinyl)-1, 2, 5-thiadiazol-3-yl] oxy], timolol. The chromatographic separation was performed using a μ-Bondapak C18 column and a mobile phase of acetonitrile:water (30:70), containing 5mM KH2PO4/K2HPO4, pH 6.5 pumped at a flow rate of 1.3 mL/min. The amperometric detector equipped with a glassy carbon electrode was operated at +1000 mV. The method was applied to the determination of timolol in urine samples obtained from a hypertensive patient under medical treatment with the pharmaceutical formulation Blocadren 10 mg (timolol 10 mg). Using a simple liquid-liquid extraction procedure, a good recovery (93.25±2.5) and separation from the urine matrix is achieved. A good reproducibility, linearity and accuracy are obtained, and the quantitation limit of 10 ng/mL, allows the method to be applied to doping analysis in human ...