Omeprazole Magnesium is a pharmaceutical active ingredient belonging to the proton pump inhibitor (PPI) class. It is the magnesium salt of racemic omeprazole and is used in pharmaceutical formulations designed to reduce gastric acid secretion. The compound is identified by CAS Number 95382-33-5, has the molecular formula C₃₄H₃₆MgN₆O₆S₂, and a molecular weight of 713.12 g/mol. The USP monograph defines Omeprazole Magnesium as the magnesium salt of omeprazole in a 2:1 stoichiometric relationship and specifies its assay on an anhydrous basis.
Omeprazole Magnesium is chemically distinct from Esomeprazole Magnesium, which represents the magnesium salt of the S-enantiomer of omeprazole. For pharmaceutical API documentation, CAS number, stereochemical identity, molecular formula and molecular weight should therefore be checked carefully before preparing specifications, technical documents or procurement records.
Omeprazole Magnesium is a magnesium salt formed from two omeprazole molecules and magnesium. The USP monograph gives the chemical formula as C₃₄H₃₆MgN₆O₆S₂ and molecular weight as 713.12 g/mol. FDA substance-registration information also identifies Omeprazole Magnesium as the ingredient substance with UNII 426QFE7XLK.
The compound is structurally related to omeprazole and contains benzimidazole and substituted pyridine structural features together with a sulfoxide group. Omeprazole Magnesium is the racemic magnesium salt, whereas Esomeprazole Magnesium is associated with the S-enantiomer. This distinction is important for API identification and quality documentation.
Omeprazole and its magnesium salt belong to the proton pump inhibitor class. After administration, omeprazole-derived active species inhibit the gastric H⁺/K⁺-ATPase proton pump, reducing the final stage of gastric acid secretion. PubChem describes Omeprazole Magnesium as a benzimidazole-derived magnesium salt with selective and irreversible proton-pump inhibitory activity.
Omeprazole Magnesium is therefore an important pharmaceutical API for the development and manufacture of acid-suppression products. Regulatory labeling for omeprazole magnesium products identifies the active ingredient as the magnesium salt of omeprazole in a 2:1 ratio. FDA labeling reports the molecular weight as 713.12 and describes the material as a white to off-white powder.
Omeprazole Magnesium is used in pharmaceutical development and formulation of products intended for acid-related gastrointestinal conditions. It is associated with delayed-release dosage forms because omeprazole compounds are sensitive to acidic environments.
The API can be relevant to:
FDA labeling for Prilosec identifies omeprazole magnesium as the active ingredient in delayed-release oral products and reports that the salt is slightly soluble in water and soluble in methanol.
Quality control of Omeprazole Magnesium should address identity, assay, water content, magnesium content, chromatographic purity and physical characteristics. The USP Omeprazole Magnesium monograph provides particularly useful numerical values for these parameters.
USP defines Omeprazole Magnesium as containing not less than 97.5% and not more than 102.0% of Omeprazole Magnesium, calculated on the anhydrous basis. The monograph also specifies water between 7.0% and 10.0%, magnesium content between 3.30% and 3.55% on an anhydrous basis, and specific rotation between −0.5° and +0.5° at 20°C under the prescribed test conditions.
The USP chromatographic-purity procedure specifies limits of 0.10% for Omeprazole N-oxide, 0.10% for Omeprazole Sulfone / Related Compound A, not more than 0.10% for any other individual impurity, and not more than 0.50% total impurities.
Identification under the USP monograph includes infrared absorption and confirmation of magnesium by measurement at the 285.2 nm magnesium emission line. The USP chromatographic method uses HPLC with UV detection at 280 nm for chromatographic purity and assay. The assay system requires a column efficiency of at least 2,000 theoretical plates and replicate-injection relative standard deviation of not more than 2.0%.
For color evaluation, the USP test prepares a methanolic solution at 20 mg/mL and specifies absorbance at 440 nm of not more than 0.1. These analytical parameters provide a strong technical basis for a CMS product page and are preferable to generic or invented specification limits.
Regulatory labeling describes Omeprazole Magnesium as a white to off-white powder with melting/degradation occurring around 200°C. The salt is reported to have a water solubility of approximately 0.25 mg/mL at 25°C and is soluble in methanol.
Some commercial chemical databases report the material as a white or almost-white hygroscopic powder and report decomposition above approximately 170°C. Because melting/decomposition behavior can vary with measurement conditions and material form, the CMS should preferably describe this as “decomposes on heating; approximately 170–200°C reported” rather than presenting one number as a universal pharmacopoeial release specification.
Omeprazole Magnesium Bulk API is relevant for pharmaceutical formulation and manufacturing programs requiring a proton pump inhibitor active ingredient. Technical procurement documentation should identify the API using CAS 95382-33-5, molecular formula C₃₄H₃₆MgN₆O₆S₂, molecular weight 713.12 g/mol, and the applicable quality standard.
Because Omeprazole Magnesium is hygroscopic and its USP water specification is 7%–10%, packaging and storage conditions are important for maintaining the material's intended quality. The cited USP monograph recommends preservation in tight containers, protection from light, and storage at room temperature.
An Omeprazole Magnesium API Manufacturer in India should maintain appropriate controls for identity, assay, water content, magnesium content, chromatographic purity and other applicable quality attributes. For pharmaceutical customers, the API should be supported by suitable technical documentation such as a Certificate of Analysis, specification sheet, analytical methods and applicable regulatory-quality documentation.
The USP monograph makes Omeprazole Magnesium particularly suitable for a technically detailed API product page because several important numerical quality requirements are publicly defined. This includes the 97.5%–102.0% assay range, 7%–10% water, 3.30%–3.55% magnesium, ≤0.50% total impurities, and specified individual impurity limits.
| 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 0.2% |
| pH (1% Solution) | 7.0%–10.0% |
| Individual Impurity | NMT 0.10% |
| Total Impurities | NMT 0.50% |
| Water Content | NMT 0.5% |
| Specific Rotation | −0.5° to +0.5° at 20°C; test solution 10 mg/mL in methanol |