PLASTIC MEMBRANE AND COATED WIRE ION-SELECTIVE ELECTRODES FOR PROPYLHEXEDRINE

Propylhexedrine (PX) ion selective electrode based on plasticized (PX)-tetraphenylboron with dioctylphthalate in poly(vinyl chloride) (PVC)-matrix. The electrode shows near Nernstian response over the concentration range 2.5 x 10(-5)-10(-1) solutions of the drug. The working pH-range of the electrode is 2.5-9.5 at 25-degrees-C. The electrode response can be considered Nernstian over the temperature range 25 - 60-degrees-C with isothermal temperature coefficient 0.00025 V/degrees-C. The selectivity coefficient of the electrode is calculated towards several inorganic cations, sugars, amines, amino acids and some other pharmaceutical preparations. Also, a coated wire ion-selective electrode based on the same ion pair was found to give a Nernstian response for a concentration range of 10(-4)-10(-2) M PXH+ solution. Propylhexedrine (2-cyclohexyl-N, 1-dimethyl-ethyl amine)(PX) is a volatile sympathomimetic amine with a local vasoconstrictor action, but when inhaled it has a little stimulating effect on the central nervous system. Many methods have been used for determination of PX depending mainly on extraction1,2, mass spectrometry3,4 and colorimetric method using tetrabromophenolphthalein5. Also, chromatographic methods were widely used for separation and determination of the drug. Among these methods are high performance chromatography6,7, adsorption chromatography8, thin-layer chromatography9,10 and gas chromatography11-13. Combined chromatographic techniques were applied depending on the use of more than one chromatographic technique like TLC-GLC-HPLC14, TLC-GLC15, TLC-GC16,17. No ion-selective electrode of any type has been ever reported for PX. In the present work, the construction and the behaviour of PX (I) ion-selective electrode is based on the PX-TPB lipophilic salt in plasticized PVC-matrix. This electrode offers an easy technique for the selective determination of PX.