Isoprenaline, also known as isoproterenol, is a synthetic sympathomimetic catecholamine and non-selective beta-adrenergic receptor agonist. It acts primarily on beta-1 and beta-2 adrenergic receptors and produces positive chronotropic and inotropic effects on the heart together with relaxation of bronchial smooth muscle.
Isoprenaline is used as a pharmaceutical active ingredient in preparations intended for specific cardiovascular applications, particularly the temporary management of certain forms of bradycardia and heart block. It has also historically been used as a bronchodilator because of its beta-2 adrenergic activity.
Isoprenaline is identified by CAS Number 7683-59-2 for the free base and is commonly supplied in pharmaceutical preparations as isoprenaline hydrochloride, CAS Number 51-30-9. The molecular formula of isoprenaline free base is C11H17NO3 and its molecular weight is 211.26 g/mol. Isoprenaline hydrochloride has the molecular formula C11H18ClNO3 and a molecular weight of 247.72 g/mol.
Isoprenaline is a catecholamine containing a phenyl ring with two hydroxyl groups, a beta-hydroxyl group and a secondary amine. The compound is structurally related to adrenaline and other beta-adrenergic agonists, but its pharmacological activity is predominantly directed toward beta-adrenergic receptors.
Isoprenaline stimulates beta-1 and beta-2 adrenergic receptors. Beta-1 receptor stimulation increases cardiac rate and contractility, while beta-2 receptor stimulation promotes relaxation of bronchial and certain vascular smooth muscles. The resulting pharmacological effects include increased heart rate, increased cardiac contractility and bronchodilation.
Isoprenaline hydrochloride is used in selected cardiovascular applications where beta-adrenergic stimulation is required. It may be used for temporary treatment of bradycardia or certain types of heart block under appropriate medical supervision. Its historical use as a bronchodilator has largely been replaced by more selective beta-2 agonists.
Pharmaceutical Isoprenaline can be characterized using validated chromatographic and spectroscopic analytical methods. HPLC may be used for assay and related-substance determination, while identity can be established using suitable chromatographic, spectroscopic and chemical identification procedures.
Quality control of Isoprenaline API should include identity, assay, related substances, water content, residual solvents, elemental impurities and other applicable parameters according to the approved drug-substance specification.
Isoprenaline should be stored in a tightly closed container under controlled pharmaceutical storage conditions and protected from excessive heat, moisture and contamination. Catecholamine compounds can be susceptible to oxidation; therefore, appropriate packaging and handling conditions should be maintained.
Isoprenaline API may be supplied for pharmaceutical manufacturing, formulation development, analytical testing and other qualified pharmaceutical applications. Product specifications, Certificate of Analysis, packaging configuration and regulatory documentation should be confirmed according to the intended application.
For Isoprenaline API requirements, customers can request product specifications, analytical documentation, Certificate of Analysis, packaging information and commercial details. Quality parameters should be evaluated against the applicable pharmaceutical specification before procurement.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.5% |
| Heavy Metals | NMT 10 ppm |
| pH (1% Solution) | 5.0 – 7.0 |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Melting Point | Approximately 208–211°C |