Chemical Properties
White Crystalline Solid
Usage
A partially reversible gastric proton pump inhibitor
Usage
anthelminthic, antiseptic, expectorant
Usage
antibacterial and antifungal agent effective against gram-positive and gram-negative bacteria, yeast and fungi
Description
Rebeprazole sodium was launched as Pariet in Japan, its first market, for the treatment of peptic ulcers including gastric and duodenal ulcers. From 4-chloro- 2,3-dimethylpyridine N-oxide, a six step synthesis allows access to the basic skeleton after successive condensations. Rabeprazole, a structural analog of Omeprazole, the first compound to have been marketed in this class up to now, is reported to be a more potent inhibitor of gastric H+/K+-adenosine triphosphate (ATPase) ; a common mechanism of action of this chemical class involves the conversion at low pH to a reactive sulphonamide that itself binds to cysteine residues located on the enzyme. Moreover, rabeprazole showed an antibacterial activity against Helicobacter Pylori, with a MIC90 of 1.56 μg/ml.
Rebeprazole sodium has a faster onset of action compared with omeprazole, but a shorter duration of action, being extensively and rapidly metabolized in several animal species. In clinical studies in patients with gastric ulcers, 10 and 20 mg rabeprazole sodium once-daily significantly inhibited basal and stimulated acid output. Rabeprazole is awaiting registration in the US for treatment of gastrooesophageal reflux disease (GORD) and other pathologic hypersecretory conditions including Zollinger-Ellison syndrome.
Definition
ChEBI: Rabeprazole sodium is an organic sodium salt. It contains a rabeprazole(1-).
Brand name
Aciphex (Eisai Medical Research)
.
General Description
Rabeprazole sodium, 2[[[4-(3-methoxypropoxy)-3-methyl-2-pyridinyl]methyl]sulfinyl]-1H-benzimidazole sodium salt (Aciphex), is a white toslightly yellowish white solid. It is very soluble in water andmethanol, freely soluble in ethanol, chloroform, and ethyl acetate,and insoluble in ether and hexane. Rabeprazole is aweak base (pyridine N, pKa 4.53) and a weak acid (benzimidazoleN-H, pKa 0.62), faciliting sodium salt formation.
Rabeprazole sodium is formulated as enteric-coated,delayed-release tablets to allow the drug to pass throughthe stomach relatively intact. After oral administration of20-mg peak plasma concentrations (Cmax) occur over arange of 2 to 5 hours (Tmax). Absolute bioavailability for a20-mg oral tablet of rabeprazole (vs. IV administration) isapproximately 52%. The plasma half-life ofrabeprazole ranges from 1 to 2 hours. The effects of foodon the absorption of rabeprazole have not been evaluated.Rabeprazole is 96% bound to human plasma proteins.Rabeprazole is extensively metabolized in the liver. Thethioether and sulfone are the primary metabolites measuredin human plasma resulting from CYP3A oxidation.Additionally, desmethyl rabeprazole is formed via the actionof CYP2C19. Approximately 90% of the drug is eliminatedin the urine, primarily as thioether carboxylic acidand its glucuronide and mercapturic acid metabolites. Theremainder of the dose is recovered in the feces. No unchangedrabeprazole is excreted in the urine or feces.
Biochem/physiol Actions
Rabeprazole sodium is gastric proton pump inhibitor. It suppresses the production of acid in the stomach by inhibiting the gastric H+/K+ATPase (hydrogen-potassium adenosine triphosphatase) at the secretory surface of the gastric parietal cell. Rabeprazole sodium has been used clinically to treat acid-reflux disorders (GERD), peptic ulcer disease, H. pylori eradication, and prevent gastroinetestinal bleeds associated with NSAID use.
Clinical Use
Gastric acid suppression
Drug interactions
Potentially hazardous interactions with other drugs
Antifungals: absorption of itraconazole and
ketoconazole reduced; avoid with posaconazole.
Antivirals: concentration of atazanavir and rilpivirine
reduced - avoid; concentration of raltegravir and
saquinavir possibly increased - avoid.
Clopidogrel: possibly reduced antiplatelet effect.
Cytotoxics: possibly reduced excretion of
methotrexate; avoid with dasatinib, erlotinib and
vandetanib; possibly reduced lapatinib absorption;
possibly reduced absorption of pazopanib.
Ulipristal: reduced contraceptive effect, avoid with
high dose ulipristal.
Metabolism
Rabeprazole is mainly metabolised via nonenzymatic
reduction and, to a lesser extent, via the cytochrome P450
isoenzymes CYP2C19 and CYP3A4. Metabolites are
excreted principally in the urine (about 90%) with the
remainder in the faeces.
storage
Store at -20°C, stored under nitrogen
