Determination of Propranolol by Capillary Electrophoresis with End-Column Amperometric Detection

Abstract

A capillary electrophoresis-amperometric detection system was developed for the determination of propranolol (PRO) at a 33 mm carbon ®ber microdisk electrode (CFE). The cyclic voltammogram, the hydrodynamic voltammograms and the effect of pH were studied. Under the optimum conditions: separation voltage 15 kV; injection 3 s at 15 kV; 10 mM pH 7.5 phosphate buffer, 1.15 V (vs. Ag=AgCl) detection potential, the detection limit (LOD) for PRO was 0.05 mM (S=N 3). The response for PRO was linear over two orders of magnitude with a linear correlation coef®cient of 0.994. The feasibility of this method was demonstrated by the detection of PRO in urine sample.Keywords: Capillary electrophoresis, End-column amperometic detection, Propranolol Propranolol (PRO) is a b-adrenergic blocking agent (pK a 9.45 [1]). The structure of PRO is given in Figure 1. It is used in the treatment of hypertension and cardiovascular disorder. But bblockers are exceptionally toxic and most of them possess a narrow therapeutic range, the difference between the lowest therapeutic and highest tolerable doses is small. Therefore it is necessary to ®nd a sensitive analytical method for the determination of PRO. Several methods have been developed to determine PRO including high performance liquid chromatography (HPLC) [17,18]. And the detection modes in these references are usually UV=vis absorbance [2±4, 7±8],¯uorescence spectrometry [6], mass spectrometry (MS) [9,11] and photodiode array detector [5]. So far no report about electrochemical detection (EC) of PRO in CE has been published. CE-EC possesses many advantages including lower injection volume and consumption of solvent, high sensitivity, selectivity comparing to other methods. In the present article, the amperometric detection (AD) method for the determination of PRO separated by capillary zone electrophoresis (CZE) was reported. The end-column AD mode is simple and sensitive. Without any modi®cation and sample concentration, the LOD of this method is several decades lower than UV detector reported [11].Before each run, the capillary is¯ushed consequently with doubly distilled water, NaOH (0.1 M), doubly distilled water and buffer for 1, 1, 1, 5 min, respectively. The proper alignment of the microelectrode with the bore of the capillary is achieved by microscope. The distance between the electrode and the end of the capillary is about 30 mm to get high signal-to-noise ratio and good reproducibility. The preparation of the CFE is same as [19]. Before use in the detection of CE, the microelectrode is polished with different kinds of Al 2 O 3 powder, washed with doubly distilled water, sonicated by an ultrasonic wave cleaner, respectively. During the experiment, the electrode tends to be poisoned and the peak currents decrease gradually without any treatment on the electrode. We found that electrochemical treatment can activate the surface of the electrode and hence improve the reproducibility. The CFE is swept 50 mV=s between À0.3 V±1.4 V (vs. Ag=AgCl) for 2 min in order to clean...

Electrochemical behavior of Propranolol and its major metabolites, 4'-hydroxypropranolol and 4'-hydroxypropranolol Sulfate, on glassy carbon electrode

“…Analogously, as for 4'OH PS, the relationship of log(I p ) vs. log(v) was examined. The dependence could be expressed by the equation: log (I p / µA) = 0.467 log (v / (mV s -1 )) -1.379 (8) with a correlation coefficient of R 2 = 0.9981. The value of the slope confirmed that the process is diffusion-controlled.…”

“…[5][6][7] PRO and 4'OH PH exhibit natural fluorescence properties, permitting the use of HPLC methods with fluorescence detectors for both compounds. Other methods that have been reported include capillary electrophoresis, [8][9][10] spectrofluorimetric 11,12 and electrochemical methods. [13][14][15] A polarographic method was used to determine the quantity of PRO in pharmaceutical formulations.…”

Ion-Transfer Voltammetric Behavior of Propranolol at Nanoscale Liquid–Liquid Interface Arrays

“…[4][5][6][7][8] Among various analytical methods such as chromatographic and spectrophotometric analysis, electrochemical techniques have attracted considerable interest due to the high efficiency and low cost. 9,10 However, the direct oxidation of propranolol at conventional electrodes, including glassy carbon electrodes, requires high overpotentials. Therefore, many attempts have been made to modify electrodes with some catalytic materials such as carbon nanotubes 11 and copper-oxide nanoparticles 12 .…”

“…Drug detection is of great importance in detection and control of substance misuse, abuse, or addiction, as well as monitoring clinical effects of chronic diseases. , (±)-Propranolol hydrochloride is a β-blocker drug which is widely used to treat various cardiovascular disorders, such as angina pectoris, myocardial infarction, and hypertension cardiac arrhythmias . The rising demands for propranolol detection have driven tremendous efforts in the development of sensitive methods for quantification of propranolol in pharmaceutical formulations. − Among various analytical methods, such as chromatographic and spectrophotometric analysis, electrochemical techniques have attracted considerable interest due to the high efficiency and low cost. , However, the direct oxidation of propranolol at conventional electrodes, including glassy carbon electrodes, requires high overpotentials. Therefore, many attempts have been made to modify electrodes with some catalytic materials such as carbon nanotubes and copper-oxide nanoparticles .…”