Rabeprazole Sodium is the sodium salt of rabeprazole, a substituted benzimidazole proton-pump inhibitor (PPI). It suppresses gastric acid secretion by inhibiting the gastric H⁺/K⁺-ATPase proton pump located on the secretory surface of gastric parietal cells. (dailymed.nlm.nih.gov)
Rabeprazole Sodium is used as an active pharmaceutical ingredient in delayed-release oral formulations for acid-related gastrointestinal disorders. The API is chemically sensitive to acidic conditions and is more stable under alkaline conditions. (dailymed.nlm.nih.gov)
The anhydrous form has the molecular formula C₁₈H₂₀N₃NaO₃S and molecular weight 381.42 g/mol. The USP specification also recognizes hydrated forms separately. (pubchem.ncbi.nlm.nih.gov)
PubChem confirms CAS 117976-90-6, formula C₁₈H₂₀N₃NaO₃S and molecular weight 381.4 g/mol. (pubchem.ncbi.nlm.nih.gov)
Rabeprazole Sodium belongs to the proton-pump inhibitor (PPI) class and is classified as a substituted benzimidazole antisecretory compound.
Rabeprazole is protonated and accumulated within the acidic environment of gastric parietal cells, where it is converted into an active sulfenamide. The active form binds to and inhibits the H⁺/K⁺-ATPase, blocking the final step of gastric acid secretion. (dailymed.nlm.nih.gov)
The pharmacodynamic effect is prolonged because inhibition of the proton pump persists beyond the relatively short plasma half-life of rabeprazole.
Rabeprazole Sodium API is used in pharmaceutical formulations for acid-related gastrointestinal conditions, including:
U.S. labeling includes delayed-release rabeprazole sodium tablets for GERD, duodenal ulcer treatment and pathological hypersecretory conditions, with combination therapy used for H. pylori eradication. (dailymed.nlm.nih.gov)
Rabeprazole Sodium is described as a white to off-white, hygroscopic powder. It is freely soluble in methanol and methylene chloride. Its stability is strongly pH-dependent: it is rapidly degraded in acidic media and is more stable under alkaline conditions. (dailymed.nlm.nih.gov)
| Property | Value |
|---|---|
| Molecular Weight | 381.42 g/mol |
| Exact Mass | 381.11230696 Da |
| H-Bond Donors | 0 |
| H-Bond Acceptors | 7 |
| Rotatable Bonds | 8 |
| TPSA | 81.5 Ų |
| Physical Form | White to off-white hygroscopic powder |
Rabeprazole Sodium API can be characterized using:
The USP monograph includes IR identification, sodium identification, assay, organic-impurity testing and specific tests for loss on drying or water depending on whether the material is anhydrous or hydrated. (turn1search0)
The current USP 2025 information identifies Rabeprazole Sodium as containing NLT 98.0% and NMT 102.0% of rabeprazole sodium, calculated on the dried basis for the anhydrous form and on the anhydrous basis for the hydrated form. (turn1search0)
The USP specification also controls organic impurities. A published USP specification identifies a total impurities limit of NMT 1.0%. (turn1search38)
The principal impurity/reference standards include Rabeprazole Related Compounds A, B, C, D, E and F, covering degradation and process-related substances such as the N-oxide, sulfide and sulfone analogues. (turn1search0)
The standard Rabeprazole Sodium record represents the sodium salt without a defined stereochemical center. However, (S)-Rabeprazole Sodium is separately identified as a stereochemically defined material, with molecular formula C₁₈H₂₁N₃NaO₃S and molecular weight 382.4 g/mol. (pubchem.ncbi.nlm.nih.gov)
Therefore, the API specification should clearly identify whether the material is the standard racemic/unspecified stereochemical form or a specifically controlled stereoisomer.
Rabeprazole Sodium should be protected from conditions that promote degradation. Current labeling describes the material as hygroscopic and pH-sensitive, with greater stability under alkaline conditions. (dailymed.nlm.nih.gov)
The USP information specifies:
Typical Rabeprazole Sodium API documentation may include:
Rabeprazole Sodium API manufacturing requires controlled synthesis, purification, sodium-salt formation, drying and analytical testing.
Particular attention should be given to chemical purity, organic impurities, moisture/hydration state, hygroscopicity and stability under acidic conditions. The final API should comply with the applicable current USP or registered specification.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 0.5% |
| Residue on Ignition | NMT 0.1% |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 7.0% |