Determination of Pantoprazole Sodium and Lansoprazole in Individual Dosage Form Tablets by Rp- Hplc Using Single Mobile Phase

A simple, sensitive and precise high performance liquid chromatographic method for the analysis of Pantoprazole sodium and lansoprazole has been developed, validated and used for the determination of compounds in commercial pharmaceutical products. The compounds were well separated an isocratically on a C18 column [Use Inertsil C18, 5μ , 150 mm x 4.6 mm] utilizing a mobile phase consisting of acetonitrile: phosphate buffer (60:40, v/v, pH 7.0) at a flow rate of 1.0 ml/min with UV detection at 230 nm. The retention time of Pantoprazole sodium and lansoprazole was found to be 2.017 min and 2.538. The procedure was validated for linearity (Correlation coefficient = 0.999). The study showed that reversed-phase liquid chromatography is sensitive and selective for the determination of Pantoprazole sodium and lansoprazole using single mobile phase. Key wards: Pantoprazole sodium, Lansoprazole, RP-HPLC, Method validation and Tablets INTRODUCTION The proton-pump inhibitor Pantoprazole sodium inhibit gastric acid by blocking the H/Kadenosine triphosphatase enzyme system (the proton pump) of the gastric parietal cell. It is used for short-term treatment of erosion and ulceration of the esophagus. The Pantoprazole sodium oral dosage forms are supplied in enteric-coated tablets.Different analytical methods are reported in the literature for the assay of Pantoprazole sodium in dosage forms and in biological fluids including spectrophotometry, TLC, HPTLC. Pantoprazole sodium is chemically Sodium 5(difluoromethoxy)-2-[[(3, 4-dimethoxy-2-pyridinyl) methyl] sulfinyl]-1H-benzimidazole sesquihydrate. Lansoprazole is chemically 2-({3-methyl-4-(2, 2, 2-trifluoroethoxy)-2-pyridyl) methyl} sulfinyl benzimidazole, is used as a gastric proton pump inhibitor. It has an empirical formula of C16H14F3N3O2S and a molecular weight of 369.36. Literature survey revealed HPTLC, spectrophotometric and spectrofluorometric methods for determination of lansoprazole in bulk, dosage forms, biological fluids and acid-induced degradation studies International Journal of Applied Biology and Pharmaceutical Technology Page: 683 Available online at www.ijabpt.com Jaya Prakash et al ISSN 0976-4550 EXPERIMENTAL Apparatus A High Performance Liquid Chromatograph system, with LC solutions data handling system (Shimadzu-LC 2010) with an auto sampler was used for the analysis. The data was recorded using LC 2010 solutions software. The purity determination performed on a stainless steel column 150 mm long, 4.6 mm internal diameter filled with Octadecyl silane chemically bonded to porous silica particles of 5 μm diameter (Inertsil C18, 5μ , 150 mm x 4.6 mm, make: Shimadzu ltd, Japan) with the mobile phase containing acetonitrile and phosphate buffer in the ratio of 60:40 (v/v pH 7.0) at ambient temperature. Flow rate was kept at 0.8 ml/min, and the elution was monitored at 260 nm. Reagents and Chemicals Pantoprazole sodium and lansoprazole working standard, used from Smilax Laboratories Limited. For the estimation of Pantoprazole sodium and lansoprazole in bulk and commercial formulations of lansoprazole brand (Pantin-20, Genex laboratories LAN, Intas laboratories), 20 tablets were obtained from retail pharmacies. Each tablet was labeled contain 20 mg of Pantoprazole sodium and 30 mg of Lansoprazole and had an expiry of not less than 365 days at the time of study. HPLC grade Sodium dihydrogen phosphate (NaH2PO4) Disodium hydrogen phosphate (Na2HPO4), Acetonitrileprocured from Merck, India. High pure water was prepared by using Millipore Milli Q plus purification system. Preparation of mobile phase: Mobile phase was prepared by mixing 700 ml of acetonitrile with 300 ml of phosphate buffer and its pH adjusted to 7.0. The mobile phase was sonicated for 15 min and then it was filtered through a 0.45 μ membrane filter paper. Preparation of stock and standard solutions: Accurately weighed 25 mg of test sample into a clean dry 50 ml volumetric flask, dissolve and dilute to the mark with mobile phase. Mark this solution as sample solution. This solution contains 0.5 mg/ml of sample. Qualified working standard of Pantoprazole sodium and lansoprazole is used to carry out validation exercise. The potency of working standard is 99.78 % and 99.85%. With the optimized chromatographic conditions, a steady baseline was recorded, the standard solution was injected and the chromatogram was recorded. This procedure were repeated to sample preparation. Assay in formulations In case of marketed formulations, five accurately weighed tablets were crushed to a fine powder and an amount equivalent to 10 mg of Pantoprazole sodium and lansoprazole was added into different 100 ml volumetric flasks and volume was made up with acetonitrile and methanol mixture. The samples were filtered through a 0.45-μmmembrane filter; different serial dilutions (3.10, 6.20, 12.40, 25μg/ml) were made from this solution in 25 ml volumetric flask and were injected for HPLC analysis. The retention time of Pantoprazole sodium and lansoprazole was found to be 2.017 min and 2.538 (figure 1 and figure 2). International Journal of Applied Biology and Pharmaceutical Technology Page: 684 Available online at www.ijabpt.com Jaya Prakash et al ISSN 0976-4550 Figure 1. Chromatogram of Pantoprazole sodium Figure 2. Chromatogram of Lansoprazole Method validation The method was validated for the parameters like specificity, range and linearity, limit of detection (LOD), limit of quantitation (LOQ), accuracy, and precision. In addition, system suitability parameters were also calculated. To demonstrate specificity in the presence of excipients used in formulation, Pantoprazole sodium was spiked (at approximately 25 μg/ml) in drug product, chromatogram was observed and compared with that of raw material. To evaluate the linearity, the LOD and LOQ of the method in reference drug, different serial dilutions (0.0980, 0.180, 0.80, 1.50, 3.10, 6.30, 12.50 and 25 μg/ml) were prepared from the standard stock solutions of Pantoprazole sodium and lansoprazole in 25 ml volumetric flasks and volume made up with diluent which is mixture of 60:40 acetonitrile & methanol. The samples were injected (10 μl) and signals from the samples were recorded which were compared with those of blank. LOD and LOQ values were calculated as signal-to-noise ratio of 3:1 and 10:1 respectively. To determine accuracy of the method, working standard of Pantoprazole sodium was prepared in triplicate at three concentration levels (10, 20 and 25 μg/ml) and analyzed. Repeatability of the method was checked by analyzing six replicate samples of Pantoprazole sodium (at the 100% concentration level) and calculating relative standard deviation (%RSD). To determine intermediate precision, standard solutions of Pantoprazole sodium and lansoprazole at eight concentration levels were analyzed three times within the same day (intra-day variation) and three other days (inter-day variation). International Journal of Applied Biology and Pharmaceutical Technology Page: 685 Available online at www.ijabpt.com Jaya Prakash et al ISSN 0976-4550 Results and Discussion