Different Chromatographic and Electrophoretic Methods for Analysis of Proton Pump Inhibitors (PPIs): A Review

Deduction of full factorial design of HPLC technique for the simultaneous analysis of meloxicam and esomeprazole in their laboratory prepared tablets

A reversed phase HPLC method with UV detection was designed for the first time for the simultaneous estimation of meloxicam and esomeprazole in their combined tablet dosage forms. Full factorial design was used for rapid optimization of the proposed method. Chromatographic separation was reached using isocratic elution on C18 column. The mobile phase was a mixture of methanol: acetonitrile: 0.05 M potassium dihydrogen phosphate buffer at pH 5, adjusted using phosphoric acid and/or NaOH when needed. The flow rate was 1 mL/min and the injection volume was 20 µL. The detection wavelength was 230 nm. The working ranges of the method were 5.0-100.0 and 10.0-100.0 µg/mL, LOD values were 0.8 and 1.8 µg/mL and LOQ values were 2.6 and 5.5 µg/mL for meloxicam and esomeprazole, respectively. The proposed method was successfully applied to their combined tablet dosage forms with acceptable % recoveries (100.4 - 100.7%) obtained. Four methods were used to evaluate the greenness of the proposed method, suggesting the acceptability of the greenness of the proposed method.

Determination of lansoprazole in pharmaceuticals using flow injection with rhodamine 6G-diperiodatoargentate (III)-chemiluminescence detection

A chemiluminescence (CL) method based on rhodamine 6G (R6G)-diperiodatoargentate (III) (silver (III) complex) reaction in acid solution is reported for the determination of lansoprazole (LNP) combined with flow injection (FI) technique. The most likely mechanism for CL reaction was elucidated considering reported data, spectrophotometric and spectrofluorimetric studies. The weak CL reaction between R6G and silver (III) complex could be magnanimously increased in the presence of LNP with a limit of detection (LOD) of 0.002 mg L^-1 (S/N = 3), the linear range of 0.01-10 mg L^-1 (R² = 0.9997, n = 7), relative standard deviations (RSD) of 1.2-3.2% (n = 4) and injection throughput of 140 h^-1 . No interference activity of commonly found excipients in LNP was detected. After LNP extraction from pharmaceutical samples, the recovery rate ranged from 93-110% (RSD, 1.4-3.3%, n = 4) was calculated. The results of proposed flow CL method were assessed with a spectrophotometric approach applying paired Student's t-test and the calculated value (0.178) was lower than the distributed value (2.20) at a 95% confidence limit.

Chiral separation in the class of proton pump inhibitors by chromatographic and electromigration techniques: An overview

Proton pump inhibitors (PPIs) are benzimidazole-derivative chiral sulfoxides, frequently used in the treatment of gastric hyperacidity-related disorders. Due to their stereoselective metabolism, the eutomeric forms of PPIs can present a more advantageous pharmacokinetic profile by comparison with the distomers or racemates. Moreover, two representatives of the class are used in therapy both as racemates and as pure enantiomers (esomeprazole, dexlansoprazole). A relatively large number of enantioseparation methods employed for the stereoselective determination of PPIs from pharmaceutical, biological, and environmental matrices were published in the past three decades. The purpose of the current overview is to provide a systematic survey of the available chiral separation methods published since the introduction of PPIs in the therapy up to the present. Analytical and bioanalytical methods using different chromatographic and electromigration techniques reported for the enantioseparation of omeprazole, lansoprazole, pantoprazole, rabeprazole, ilaprazole, and tenatoprazole are included. The analytical conditions of the presented methods are summarized in three comprehensive tables, while a critical discussion of the applied techniques, possible mechanism of enantiorecognition, and future perspectives on the topic are also presented.

Simultaneous Quantitative Analysis of Six Proton-Pump Inhibitors with a Single Marker and Evaluation of Stability of Investigated Drugs in Polypropylene Syringes for Continuous Infusion Use

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.

Lansoprazole Determination in Pharmaceutical Formulations by Flow Injection Coupled with Acidic KMnO4-Quinine Chemiluminescence System

A simple and rapid flow injection chemiluminescence (FI-CL) method based on the reaction of potassium permanganate (KMnO₄) and quinine was established for the determination of lansoprazole in pharmaceutical formulations. A linear calibration curve was achieved over the range from 0.01 to 20.0 mg L^-1 LNP (R² = 0.9997 (n = 8); RSD = 1.1 - 3.7% (n = 4)) with a limit of detection of 3.0 × 10^-3 mg L^-1 (S/N = 3) and injection throughput of 150 h^-1. By applying the Student t-test (calculated t-test value: t = 1.059907664, and tabulated t-distributed (95%) = 2.200985) it was found that the proposed method and reported spectrophotometric method were not significantly different. The LNP was efficiently extracted and the recovery of LNP from the spiked pharmaceutical formulations was in the range of 91.0 - 105.9% (%RSD = 1.6 - 3.6, n = 4). No significant interference activity was detected from the excipients commonly found in the drug samples analyzed. The possible chemiluminescence emission mechanism is discussed briefly.

Chiral separation of lansoprazole and rabeprazole by capillary electrophoresis using dual cyclodextrin systems

Novel capillary electrophoresis methods using CDs as chiral selectors were developed and validated for the chiral separation of lansoprazole and rabeprazole, two proton pump inhibitors. Fourteen different neutral and anionic CDs were screened at pH 4 and 7 in the preliminary analysis. Sulfobutyl-ether-β-CD with a degree of substitution of 6.5 and 10 at neutral pH proved to be the most suitable chiral selector for both compounds. Various dual CD systems were also compared, and the possible mechanisms of enantiomer separation were investigated. A dual selector system containing sulfobutyl-ether-β-CD degree of substitution 6.5 and native γ-CD proved to be the most adequate system for the separations. Method optimization was carried out using an experimental design approach, performing an initial fractional factorial screening design, followed by a central composite design to establish the optimal analytical conditions. The optimized methods (25 mM phosphate buffer, pH 7, 10 mM sulfobutyl-ether-β-CD/20 mM γ-CD, +20 kV voltage; 17°C temperature; 50 mbar/3 s injection, detection at 210 nm for lansoprazole; 25 mM phosphate buffer, pH 7, 15 mM sulfobutyl-ether-β-CD/30 mM γ-CD, +20 kV voltage; 18°C temperature; 50 mbar/3 s injection, detection at 210 nm for rabeprazole) provided baseline separation for lansoprazole (R_s = 2.91) and rabeprazole (R_s = 2.53) enantiomers with favorable migration order (in both cases the S-enantiomers migrates first). The optimized methods were validated according to current guidelines and proved to be reliable, linear, precise, and accurate for the determination of 0.15% distomer as chiral impurity in dexlansoprazole and dexrabeprazole samples.