Simple, rapid and economic Spectrophotometric method was developped for
the assay of certain proton pump inhibitors (PPIs) belonging to benzimidazole
derivatives namely; omeprazole, rabeprazole, pantoprazole and lansoprazole.
The method depends on the reaction of the cited proton pump inhibitors
with diazotized p-nitroaniline in alkaline medium using 1.5 N NaOH and
dimethylformamide. The produced green color was measured at 590 nm for
omeprazole, rabeprazole and 610 nm (for, pantoprazole and lansoprazole).
The recorded absorbances obey Beer's law for 5-30, 10-35, 5-40 and 5-40 µg
ml-1
omeprazole, rabeprazole, pantoprazole and lansoprazole, respectively
with good correlation coefficients (0.9996-0.9999). The limits of detection
and quantification are also reported for the studied method. Intra-day and
inter-day precision as well as accuracy and robustness of the method have
been evaluated. The proposed method was successfully applied to the assay
of the studied proton pump inhibitors in pharmaceutical dosage forms and
the results were statistically compared with those of reported method by
applying Student’s t-test and F-test where no significance differences were
observed.