Polarographic determination of propranolol in pharmaceutical formulation

Propranolol was reacted with nitric acid to give nitropropranolol and was then measured in Britton-Robinson solutions in the pH range 2.0-12.0 by differential-pulse polarography. Nitropropranolol gave rise to a well-resolved differential-pulse polarographic peak at pH 2.0. A linear calibration graph in the range 5.0 x 10(-7)-5.0 x 10(-5) M and a detection limit of 5 nM was obtained. The relative standard deviation was 1.95% (n = 10) at 5 x 10(-6) M. The effect of common exceipient on the peak height was evaluated. The method was applied for the determination of the drug in the tablet dosage form.