Determination of ephedrine hydrochloride in pharmaceutical formulations and in urine samples using a new coated graphite electrode

الملخص EN

A novel approach for the determination of ephedrine hydrochloride (EDCl) in pharmaceutical formulations and in urine samples is presented.

New coated graphite selective electrode for EDCl based on ephedrinephosphotungstate (PD-PT) as an ion-exchanger dissolved in plasticizer DOP and their potentiometric characteristics were discussed.

The electrode exhibited a good Nernstian slope of 57.8±0.03 mV/decade with a linear concentration range from 8.5 x 10-7 to 1.0 x10-2 M for the ephedrine ion.

The limit of detection was 4.5 x 10-7 M.

It had response time of 8 sec, useable in pH range of 3.2 – 7.3 and temperature of 20–60 oC.

The coated electrode shows clear discrimination of ephedrine hydrochloride from several inorganic, organic ions, sugars and some common drug excipients.

The sensor was applied for determination of ephedrine hydrochloride in urine and in pharmaceutical formulations using potentiometric determination, standard addition and the calibration curve methods.

The results are satisfactory with excellent percentage recovery comparable or better than those obtained by other routine methods.