Objective: We developed and validated a simple, convenient and reproducible method for simultaneous estimation of six proton-pump inhibitors (PPIs), omeprazole (OPZ), esomeprazole (EOPZ), lansoprazole (LPZ), pantoprazole (PPZ), rabeprazole (RPZ) and ilaprazole (IPZ) in pharmaceutical dosage forms by a single marker. Meanwhile, the stability of the cited PPIs in 0.9% sodium chloride injection stored in polypropylene syringes up to 48 hours for continuous infusion use was investigated.
Materials and Methods: The chromatographic separation was achieved on an InterSustain^® C₁₈ column (150 × 4.6 mm, 5 μm). The isocratic mobile phase made up of 0.05 M potassium dihydrogen phosphate buffer (pH 4.0): acetonitrile (65:35, v/v) was pumped through the column at a temperature maintained at 30°C and a flow rate of 1.0 mL/min. The relative retention time, UV spectral similarity and relative correction factors between OPZ and the other five PPIs were calculated and investigated using the quantitative analysis of multi-components with a single marker (QAMS) method. The stability study examined physical parameters, pH values and drug concentrations of the PPIs mixtures.
Results: Under these conditions, all cited PPIs were separated simultaneously at a retention time of 6.0, 7.3, 7.3, 9.9, 12.5 and 13.9 min for RPZ, OPZ, EOPZ, IPZ, PPZ and LPZ, respectively, with a total run time less than 20.0 min. Comparative analysis results indicated that there were no significant differences observed between the QAMS method and the external standard method. The percentage of initial concentration of each PPI gradually decreased during the storage time.
Conclusion: The proposed method, which is selective, economical and accurate, was applied successfully for determination of the cited PPIs in their respective pharmaceutical dosage forms. Admixtures of OPZ, EOPZ, PPZ, IPZ in 0.9% sodium chloride injection were stable for 24 hours and LPZ, RPZ in 0.9% sodium chloride injection were stable for 8 hours in polypropylene syringes.
Keywords: proton-pump inhibitors, quantitative analysis of multi-components with a single marker, relative correction factor, relative retention time, HPLC, stability