Propranolol Hydrochloride is the hydrochloride salt of propranolol, a synthetic non-selective beta-adrenergic receptor blocker belonging to the propanolamine class. It is widely recognized as an important pharmaceutical active ingredient used in the development and manufacture of cardiovascular and other therapeutic formulations. Propranolol Hydrochloride has the molecular formula C16H21NO2·HCl and a molecular weight of 295.80 g/mol. Its CAS Number is 318-98-9. PubChem identifies Propranolol Hydrochloride as the hydrochloride form of propranolol and reports a molecular weight of 295.80 g/mol.
Propranolol Hydrochloride is generally supplied as a white or almost white crystalline powder. Pharmacopoeial references describe it as soluble or freely soluble in water and soluble in selected alcohols, with the precise solubility classification depending on the pharmacopoeia and test conditions. Japanese Pharmacopoeia information describes the material as freely soluble in methanol, soluble in water and acetic acid, and sparingly soluble in ethanol.
The API is normally handled as a racemic pharmaceutical substance containing the (RS) form. Propranolol itself has two enantiomers, with the S(-)-enantiomer having substantially greater beta-adrenergic receptor binding affinity.
Product Name: Propranolol Hydrochloride
CAS Number: 318-98-9
Molecular Formula: C16H21NO2·HCl
Molecular Weight: 295.80 g/mol
Chemical Class: Beta-adrenergic antagonist / propanolamine
Appearance: White or almost white crystalline powder
API Form: Hydrochloride salt
Pharmacopoeial References: USP, Ph. Eur./BP, JP and International Pharmacopoeia references
USP 2025-based information specifies Propranolol Hydrochloride content at 98.0%–102.0% on the dried basis and uses a liquid chromatographic assay with UV detection at 292 nm.
Propranolol Hydrochloride is an established pharmaceutical active ingredient associated with beta-adrenergic receptor blockade. Propranolol-containing medicines have applications in cardiovascular therapy and other clinical areas where beta-blockade is indicated. PubChem describes propranolol as a beta-adrenergic antagonist and notes its established use in conditions including hypertension and cardiac disorders.
For pharmaceutical manufacturing, the API is valued for its established pharmacological profile, defined chemical identity, and availability under recognized pharmacopoeial quality standards. It may be used as a starting active ingredient for various oral and other pharmaceutical dosage forms, subject to the applicable regulatory requirements and approved formulation.
Quality evaluation of Propranolol Hydrochloride includes identity testing, assay, related-substance analysis, loss on drying, residue on ignition, pH and other applicable physicochemical tests.
The current USP-based monograph uses infrared identification, chromatographic identity comparison and chloride identification. Its assay is performed by liquid chromatography and specifies 98.0%–102.0% on the dried basis. USP-based related-substance controls include Propranolol Related Compound A, propranolol dimer, dinaphthyl glycerol and unspecified impurities. The acceptance limits reported for these impurities are 0.1%, 0.1%, 0.1% and 0.10%, respectively, with total impurities NMT 0.4% and a reporting threshold of 0.05%.
The USP-based specification also gives Loss on Drying NMT 0.5%, determined at 105°C for 4 hours, and Residue on Ignition NMT 0.1%.
Japanese Pharmacopoeia specifies pH 5.0–6.0 for a solution prepared by dissolving 0.5 g in 50 mL of water, equivalent to a 1% w/v solution. JP also specifies a melting point of 163–166°C and a heavy-metals limit of NMT 20 ppm.
Propranolol Hydrochloride API is manufactured with emphasis on consistent chemical quality, controlled processing, analytical verification and appropriate documentation. Pharmaceutical manufacturers require reproducible API quality to support formulation development, production and regulatory compliance.
Manufacturing controls may include raw-material qualification, controlled processing conditions, validated analytical procedures, impurity profiling, drying controls and batch-wise quality testing. Depending on the intended market and regulatory requirement, batches may be evaluated against applicable USP, EP/BP, JP or customer-specific specifications.
Propranolol Hydrochloride should be packed in suitable well-closed containers that protect the material from environmental exposure. Pharmacopoeial references specify controlled storage conditions, while Japanese Pharmacopoeia notes that the material can gradually become yellowish-white to light brown on exposure to light.
Appropriate packaging, controlled humidity and protection from excessive light help maintain the physical and chemical quality of the API during storage and transportation.
Typical pharmaceutical documentation can include:
Propranolol Hydrochloride is a well-established beta-adrenergic pharmaceutical API with recognized pharmacopoeial standards. Its defined chemical identity, established analytical methods and controlled impurity profile make it suitable for pharmaceutical manufacturing and formulation development.
The combination of pharmacopoeial testing, controlled manufacturing practices, batch consistency and documentation supports the requirements of pharmaceutical companies, formulation developers and regulated markets.
| 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% |
| Heavy Metals | NMT 20 ppm |
| pH (1% Solution) | 5.0–6.0 |
| Individual Impurity | NMT 0.10% |
| Total Impurities | NMT 0.40% |
| Melting Point | 163–166°C |