A simple, sensitive and selective HPLC method with UV detection (284 nm) was developed and validated for quantitation of rabeprazole in human plasma, the newest addition to the group of proton-pump inhibitors. Following solid-phase extraction using Waters Oasistrade mark SPE cartridges, the analyte and internal standard (Pantoprazole) were separated using an isocratic mobile phase of 5 mM ammonium acetate buffer (pH adjusted to 7.4 with sodium hydroxide solution)/acetonitrile/methanol (45/20/35, v/v) on reverse phase Waters symmetry C(18) column. The lower limit of quantitation was 20 ng/mL, with a relative standard deviation of less than 8%. A linear range of 20-1000 ng/mL was established. This HPLC method was validated with between- and within-batch precision of 2.4-7.2% and 2.2-7.3%, respectively. The between- and within-batch bias was -1.7 to 2.6% and -2.6 to 2.1%, respectively. Frequently coadministered drugs did not interfere with the described methodology. Stability of rabeprazole in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 3 months storage in a freezer. This validated method is sensitive, simple and repeatable enough to be used in pharmacokinetic studies.

A new sensitive column-switching high-performance liquid chromatographic (HPLC) method with ultraviolet detection was developed for the simultaneous determination of rabeprazole, a proton pump inhibitor, and its active metabolite, rabeprazole thioether in human plasma. Rabeprazole, its thioether metabolite and 5-methyl-2-[(4-(3-methoxypropoxy)-3-methyl pyridin-2-yl) methyl sulfinyl]-1H-benzimidazole, as an internal standard were extracted from 1 ml of plasma using diethyl ether-dichloromethane (9:1, v/v) mixture and the extract was injected into a column I (TSK-PW precolumn, 10 microm, 35 mmx4.6mm I.D.) for clean-up and column II (C18 Grand ODS-80TM TS analytical column, 5 microm, 250 mmx4.6 mm I.D.) for separation. The peak was detected with an ultraviolet detector set at a wavelength of 288 nm, and the total time for chromatographic separation was approximately 25 min. Mean absolute recoveries were 78.0 and 88.3% for rabeprazole and rabeprazole thioether, respectively. Intra- and inter-day coefficient variations were less than 6.5 and 4.5% for rabeprazole, 3.6 and 5.3% for rabeprazole thioether, respectively, at the different concentration ranges. The validated concentration ranges of this method were 1-1000 ng/ml for rabeprazole and 3-500 ng/ml for rabeprazole thioether. The limits of quantification were 1 ng/ml for rabeprazole and 3 ng/ml for rabeprazole thioether. The method was suitable for therapeutic drug monitoring and was applied to pharmacokinetic study in human volunteers.

A highly selective, sensitive and accurate HPLC method has been developed and validated for the estimation of four proton-pump inhibitors (PPI), lansoprazole (LPZ), omeprazole (OPZ), pantoprazole (PPZ) and rabeprazole (RPZ), with 500 microL human plasma using zonisamide as an internal standard (IS). The sample preparation involved simple liquid-liquid extraction of LPZ, OPZ, PPZ and RPZ and IS from human plasma with ethyl acetate. The baseline separation of all the peaks was achieved with 0.1% triethylamine (pH 6.0):acetonitrile (72:28, v/v) at a flow rate of 1 mL/min on a Zorbax C(8) column. The total chromatographic run time was 11.0 min and the simultaneous elution of IS, OPZ, RPZ, PPZ and LPZ occurred at approximately 2.42, 4.45, 5.02 and 9.37 min, respectively. The method was proved to be accurate and precise at linearity range of 20.61-1999.79 ng/mL with a correlation coefficient (r) of >or=0.999. The limit of quantitation for each of the PPI studied was 20.61 ng/mL. The intra- and inter-day precision and accuracy values were found to be within the assay variability limits as per the FDA guidelines. The developed assay method was applied to a pharmacokinetic study in human volunteers.

OBJECTIVE:To evaluate the relative bioavailability of a new formulation containing 5 mg mosapride and 10 mg rabeprazole (T) and compare it with the branded formulations of both drugs co-administered in separate tablets (R) to meet the regulatory requirements of bioequivalence in Argentina. METHODS:A randomized-sequence, open-label, two-period crossover study was conducted on 24 healthy Caucasian volunteers in a fasting state. A single oral dose of either T or R formulations was followed by a 7-day washout period. Blood samples for mosapride were collected before administration (baseline) and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 18, and 24 h after administration. Samples for rabeprazole were taken baseline and at 1, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8 and 10 h after dosing. Mosapride and rabeprazole concentrations were determined using a validated LC-MS/MS method. Adverse events were monitored based on clinical parameters and volunteer reports. RESULTS:The geometric means (90% CI) C(max) for mosapride in T and R were 23.13 (20.05-39.45) and 23.09 (21.69-32.37) ng/mL, the AUC(0-)(t) were 70.80 (66.23-102.37) and 70.81 (66.35-93.26) ng h/mL and the AUC(0-∞) were 74.05 (69.29-106.11) and 74.98 (70.43-97.77) ng h/mL. For rabeprazole T and R the C(max) were 197.42 (186.12-239.91) and 195.50 (186.08-250.07) ng/mL, the AUC(0-)(t) were 294.90 (275.13-374.15) and 296.96 (280.11-387.89) ng h/mL and the AUC(0-∞) were 301.12 (280.78-380.82) and 304.07 (286.60-394.21), respectively. No differences were detected between the formulations. The T/R ratios (90% CI) for C(max), AUC(0-)(t) and AUC(0-∞) were 100.17% (82.35-121.84), 99.99% (87.58-114.16) and 98.77% (87.02-112.11) for mosapride, and 100.99% (85.14-119.77), 99.31% (84.74-116.38) and 99.03% (85.07-115.28) for rabeprazole. No subject complained of adverse events. CONCLUSIONS:In this single-dose study, the mosapride/rabeprazole tablets (test formulation) met the criterion for bioequivalence with the reference formulations. Study limitations include single-dose, open-label design, and a small sample of healthy volunteers.

BACKGROUND:A sprinkle capsule formulation containing enteric-coated, delayed-release rabeprazole granules is being developed for the treatment of children with gastrointestinal reflux disease. The granules are designed to be mixed with vehicles that facilitate delivery to children, who may be unable to swallow solid formulations. OBJECTIVE:The primary objective of this study-conducted on the sponsor's initiative-was to compare the bioavailability of rabeprazole granules when mixed with various dosing vehicles (small amount of soft food or infant formula) with that of a rabeprazole suspension with inactive vehicle granules (reference), to determine which dosing vehicle can be used to deliver rabeprazole in children. Tolerability was also assessed. METHODS:This single-center, single-dose, randomized, open-label, 5-period crossover study was conducted in 35 healthy adult subjects. In a randomized sequence, fasting subjects received a single dose of 10-mg rabeprazole granules per treatment period, mixed with small amounts of 1 of 5 dosing vehicles (a strawberry-flavored suspension of rabeprazole granules with inactive vehicle granules reconstituted with water, yogurt [1 tablespoon], applesauce [1 tablespoon], or infant formula [5 mL], or a suspension of rabeprazole granules with inactive vehicle tablet reconstituted with water). Full plasma pharmacokinetic (PK) profiles of rabeprazole and its thioether metabolite were collected; concentrations were estimated via LC-MS/MS. PK properties were estimated using noncompartmental methods; 90% CIs around least squares mean test-to-reference ratios were calculated for C(max) and AUC values. All treatment-emergent adverse events (TEAEs) were recorded and assessed for severity (mild, moderate, or severe) and relationship to study drug. RESULTS:A total of 35 subjects were enrolled (mean age, 38 years; 54.3% female; 100% white; mean weight, 71.4 kg). Thirty-four subjects completed the study. Rabeprazole and rabeprazole thioether plasma PK properties were comparable between all of the dosing vehicles tested. Median T(max) was 2.5 to 3.0 hours, and mean elimination half-life was 1.27 to 1.43 hours. The 90%CIs for the least squares mean ratios for rabeprazole and rabeprazole thioether exposure were within the 80% to 125% bioequivalence limits for all relevant comparisons. All TEAEs were of mild or moderate intensity, with headache being the most commonly reported; 21 subjects (60%) experienced TEAEs during the study. No deaths or serious AEs were reported during the study; 1 subject experienced a TEAE (urinary tract infection) that led to the discontinuation of treatment. CONCLUSION:In these healthy adult subjects, the bioavailability of rabeprazole granules was comparable between all of the dosing vehicles tested, and rabeprazole was well tolerated. Soft food suitable for young children or infant formula may be appropriate for use as dosing vehicles for rabeprazole granules.

A novel Liquid Chromatography-tandem mass spectrometry (LC-MS/MS) method is presented for the quantitative determination of two potential genotoxic impurities (PGIs) in rabeprazole active pharmaceutical ingredient (API). In order to overcome the analytical challenges in the trace analysis of PGIs, a development procedure supported by Quality-by-Design (QbD) principles was evaluated. The efficient separation between rabeprazole and the two PGIs in the shortest analysis time was set as the defined analytical target profile (ATP) and to this purpose utilization of a switching valve allowed the flow to be sent to waste when rabeprazole was eluted. The selected critical quality attributes (CQAs) were the separation criterion s between the critical peak pair and the capacity factor k of the last eluted compound. The effect of the following critical process parameters (CPPs) on the CQAs was studied: %ACN content, the pH and the concentration of the buffer salt in the mobile phase, as well as the stationary phase of the analytical column. D-Optimal design was implemented to set the plan of experiments with UV detector. In order to define the design space, Monte Carlo simulations with 5000 iterations were performed. Acceptance criteria were met for C column (50×4mm, 5μm) and the region having probability π≥95% to achieve satisfactory values of all defined CQAs was computed. The working point was selected with the mobile phase consisting ‎of ACN, ammonium formate 11mM at a ratio 31/69v/v with pH=6,8 for the water phase. The LC protocol was transferred to LC-MS/MS and validated according to ICH guidelines.

PURPOSE:This study was designed to investigate the antisecretory activity of rabeprazole administered once daily in doses of 5, 10, 20, and 40 mg and different cytochrome P450 2C19 (CYP2C19) genotypes on gastric pH in healthy individuals. Additional objectives were delineating the nighttime from the daytime effect and determining the relationships between the pharmacokinetics and pharmacodynamics of rabeprazole. METHODS:Eight individuals of each of the three genotypes of CYP2C19-homozygous extensive metabolizers (homo-EMs), heterozygous EMs (hetero-EMs), and poor metabolizers (PMs)-were recruited. Twenty-four individuals received a once-daily dose, with dosing interval 24 h of 5, 10, 20, or 40 mg rabeprazole for 5 days in a 4-period crossover fashion. Twenty-four-hour intragastric pH and plasma rabeprazole concentrations were determined on day 5. RESULTS:A dose-dependent increase in median pH and in pH 4 holding time was observed across all CYP2C19 genotypes. When rabeprazole was increased from 20 mg to 40 mg, the differences and 95% confidence intervals (CIs) of nighttime pH 4 holding time between 40 mg and 20 mg in homo-EMs, hetero-EMs, and PMs were 8.0% (-5.0% -21.0%), 28.7% (15.7% -41.6%), and 16.9% (3.9% -29.9%), respectively. The relationship between the area under the plasma concentration-time curve up to the last time point at which rabeprazole was quantifiable (AUC(0-t)) and the pH 4 holding time could be described using a sigmoid maximum effect (E(max)) model. CONCLUSIONS:Our data demonstrate that increasing rabeprazole dose up to 40 mg once daily results in an increasing pharmacodynamic effect, which is most apparent for the control of nocturnal gastric acid secretion.

Corneal transplantation is an effective treatment to corneal blindness. However, the immune rejection imperils corneal allograft survival. An interventional modality is urgently needed to inhibit immune rejection and promote allograft survival. In our previous study, subconjunctival injections of bone marrow-derived mesenchymal stem cells (BM-MSCs) into a rat model of corneal allograft rejection extended allograft survival for 2 d. In this study, we sought to generate IL-10-overexpressing BM-MSCs, aiming to boost the survival-promoting effects of BM-MSCs on corneal allografts and explore the molecular and cellular mechanisms underlying augmented protection. A population of IL-10-overexpressing BM-MSCs (designated as IL-10-BM-MSCs) were generated by lentivirus transduction and FACS purification. The self-renewal, multi-differentiation, and immunoinhibitory capabilities of IL-10-BM-MSCs were examined by conventional assays. The IL-10-BM-MSCs were subconjunctivally injected into the model of corneal allograft rejection, and the allografts were monitored on a daily basis. The expression profiling of long noncoding RNA (lncRNA) in the allografts was revealed by RNA sequencing and verified by quantitative real-time PCR. The infiltrating immune cell type predominantly upregulating the lncRNA expression was identified by RNAscope hybridization. The function of the upregulated lncRNA was proved by loss- and gain-of-function experiments both and . The IL-10-BM-MSCs possessed an enhanced immunoinhibitory capability and unabated self-renewal and multi-differentiation potentials as compared to plain BM-MSCs. The subconjunctivally injected IL-10-BM-MSCs reduced immune cell infiltration and doubled allograft survival time (20 d) as compared to IL-10 protein or plain BM-MSCs in the corneal allograft rejection model. Further, IL-10-BM-MSCs significantly upregulated lncRNA 003946 expression in CD68 macrophages infiltrating corneal allografts. Silencing and overexpressing lncRNA 003946 in macrophage cultures abolished and mimicked the IL-10-BM-MSCs' suppressing effects on the macrophages' antigen presentation, respectively. In parallel, knocking down and overexpressing the lncRNA abrogated and simulated the survival-promoting effects of IL-10-BM-MSCs on corneal allografts, respectively. The remarkable protective effects of IL-10-BM-MSCs support further developing them into an effective interventional modality against corneal allograft rejection. IL-10-BM-MSCs promote corneal allograft survival mainly through upregulating a novel lncRNA expression in graft-infiltrating CD68 macrophages. LncRNA, for the first time, is integrated into an IL-10-BM-MSC-driven immunomodulatory axis against the immune rejection to corneal allograft.