Abstract:
Chemometric stability indicating methods are presented for the determination of rabeprazole sodium in
presence of its acid induced degradation products using spectrophotometry, differential pulse polarography and
differential pulse anodic voltammetry at a glassy carbon electrode. The applied chemometric techniques are
multivariate ones including classical least squares (CLS), principal component regression (PCR) and partial
least squares (PLS). A difference spectrophotometric (∆A) method has also been applied. To develop the
multivariate calibrations, a training set was used, consisting of 20 mixture solutions of rabeprazole sodium and
its degradation products. These mixtures show percentage degradation ranging from 0.5-65%, 0.5-95% and 0.6-
75 % for the spectrophotometric, polarographic and anodic voltammetric calibrations, respectively. The UV
absorbances were recorded in 0.1 M NaOH within the wavelength range 220-340 nm at 2 nm intervals. The
polarograms and anodic voltammograms were recorded in Britton- Robinson buffer (pH 8.0) within the
potential range -500 to -1508 and 400 to 1192 mV at 6 mV intervals with a pulse amplitude of -100 and 50 mV,
sweep rate of 15 and 10 mV s-1 and pulse interval of 0.4 and 0.6 s for the polarographic and anodic
voltammetric methods, respectively. All the studied methods have been validated and successfully applied to
the determination of rabeprazole sodium in tablet dosage form. The results were statistically compared to those
obtained using a published HPLC method. No significant difference has been found.
