Salbutamol Sulfate is the sulfate salt of salbutamol, also known as albuterol in the United States. It is a selective short-acting β₂-adrenergic receptor agonist used as a bronchodilator in pharmaceutical products for respiratory conditions including asthma and chronic obstructive pulmonary disease. Current U.S. labeling identifies albuterol sulfate as the official U.S. generic name and salbutamol sulfate as the WHO-recommended name.
Salbutamol Sulfate API is used as the active pharmaceutical ingredient in respiratory formulations such as inhalation products and other dosage forms. The substance is a racemic sulfate salt of salbutamol. Current U.S. labeling describes albuterol sulfate as a relatively selective β₂-adrenergic bronchodilator and identifies it as a white to off-white crystalline solid that is soluble in water and slightly soluble in ethanol.
The pharmaceutical salt is represented by the empirical formula (C₁₃H₂₁NO₃)₂·H₂SO₄ and has a molecular weight of 576.7 g/mol according to current DailyMed labeling. Salbutamol itself has the molecular formula C₁₃H₂₁NO₃ and molecular weight 239.31 g/mol.
Salbutamol Sulfate contains the salbutamol active moiety together with sulfuric acid in the pharmaceutical salt form. PubChem identifies CAS 51022-70-9 and 39971-61-4 among the substance's identifiers/synonyms.
Salbutamol Sulfate is primarily used in respiratory medicines designed to produce bronchodilation. It is incorporated into pharmaceutical formulations intended for relief or prevention of bronchospasm associated with reversible obstructive airway disorders. Inhalation is an important route because the active ingredient can act directly on bronchial smooth muscle.
Salbutamol acts predominantly as a β₂-adrenergic receptor agonist. Activation of β₂ receptors in bronchial smooth muscle promotes smooth-muscle relaxation and airway dilation. This pharmacological activity makes Salbutamol Sulfate an established active ingredient for bronchodilator formulations.
Quality control of Salbutamol Sulfate API generally includes identification, assay, water determination, residue on ignition or sulfated ash, chromatographic purity/related substances and other applicable pharmaceutical quality tests.
The USP Albuterol Sulfate monograph includes infrared identification, UV identification, sulfate identification and chromatographic identification. It specifies water NMT 0.5% and residue on ignition NMT 0.1%.
The International Pharmacopoeia 2025 provides additional compendial controls, including sulfated ash NMT 1.0 mg/g, loss on drying NMT 5.0 mg/g, related-substance testing and an assay based on titration with 0.1 mol/L perchloric acid.
Manufacturing of Salbutamol Sulfate API requires controlled synthesis, salt formation, purification, drying and analytical release testing. Pharmaceutical manufacturing controls should address identity, purity, assay, residual solvents, water, inorganic residues and relevant organic impurities according to the applicable specification and market requirements.
Salbutamol Sulfate is described in current U.S. labeling as a white to off-white crystalline solid. It is soluble in water and slightly soluble in ethanol.
Salbutamol Sulfate API should be stored in appropriately closed pharmaceutical-grade packaging under controlled conditions established by validated stability data and the applicable API specification. The USP monograph specifies preservation in well-closed, light-resistant containers.
Typical documentation for Salbutamol Sulfate API may include:
A qualified Salbutamol Sulfate API manufacturer should maintain controlled pharmaceutical manufacturing systems, validated analytical procedures and appropriate quality documentation. Consistent control of assay, purity, water, inorganic residues and related substances is important for API quality and subsequent formulation performance.
| 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 0.5% |