Propranolol hydrochloride, 1-(isopropylamino)-3-(1-napthyloxy)-2-propanol hydrochloride, is a beta-adrenergic receptor blocking agent that is prescribed for its antihypertensive, antianxiety, anticovulsant and antianginal effects. In some pharmacopoeia, propranolol hydrochloride is analyzed by titrimetrical method in non-aqueous media [1] (non-aqueous acidimetric method), spectrophotometric method [1-2], and high-performance liquid chromatographic method (HPLC) [2]. Numerous methods for the determination of propranolol hydrochloride in pharmaceutical formulation has been proposed in the literature, such as colorimetry and, spectrophotometry [3][4][5][6][7], phosphorimetry [8], HPLC [9][10][11], kinetic determination [12], a.c. oscillopolarographic titration [13] and conductometry [14]. In the non-aqueous titration method (acidimetric method), because of the small pH ranges which usually take place as the titration ends, it is difficult to apply this method for the determination of lower concentration range of the drug in the pharmaceutical preparations. Colored and turbid solutions interfere with the measurement of the absorbance in spectrophotometric method. Tedious sample preparation is often required in the chromatographic methods. Ion-selective electrodes (ISEs) or sensors have been considered as an attractive technique in the analysis of drugs due to the larger concentration range of analyte determined, reasonable selectivity, simple procedures which require no prior separation or sample preparation, and the accuracy of the analytical information [15,16]. For the determination of propranolol using ion-selective electrodes in pharmaceutical preparations, Zhang and co-workers [17] described the propranolol ion selective PVC membrane electrode in which the electroactive compounds or ion-pair complexes, propranolol-dinonyl naphalenesulphonate (DNNS) or propranolol-tetra(2-chloro-phenyl) borate (CITPB), in the membrane, were obtained in situ by soaking DNNS/PVC or CITPB/PVC membranes in the propranolol solution. However, the long conditioning soaking time (24 h) of the electrode was required and a higher detection limit of 2.5~4.0 × 10 -6 M of propranolol was reported. In this paper, the development of a novel propranolol ion-selective PVC membrane electrode is described. The electrode is successfully applied to analysis of propranolol hydrochloride in pharmaceutical formulation.
Experimental section Reagents and materialsPropranolol hydrochloride was obtained in the pure raw material and in tablet dosage formulations from Changzhou Pharmaceutical Chemicals Works (Jiangsu, China). All reagents and solvents were of analytical reagent grade and deionized water was used throughout. Abstract. A novel ion selective PVC membrane electrode for determination of propranolol is developed. Silicotungstic acid is used as the counter ion and diisononyl phthalate (DNP) used as the plastizer. The electrode exhibits excellent potential response properties, showing a Nernstian response in the concentration of 3.0 × 10 -6~2 .6 × ...
