Naphazoline is a synthetic imidazoline derivative and alpha-adrenergic receptor agonist used primarily in ophthalmic and nasal pharmaceutical formulations. It produces local vasoconstriction by stimulating alpha-adrenergic receptors in blood vessels.
Naphazoline is commonly used in pharmaceutical products intended for the temporary relief of ocular redness and nasal congestion. It is available in pharmaceutical formulations in free-base and salt forms, with naphazoline hydrochloride being a commonly used form.
Naphazoline is a specialized ophthalmic and nasal pharmaceutical API used in the development and manufacture of formulations for local vasoconstrictor applications.
Important API quality attributes include identity, assay, related substances, water content, residue on ignition, residual solvents, elemental impurities and physical characteristics, according to the applicable specification.
CAS Number: 835-31-4
Molecular Formula: C14H14N2
Molecular Weight: 210.28 g/mol
Chemical Name: 2-(Naphthalen-1-ylmethyl)-4,5-dihydro-1H-imidazole
Drug Class: Alpha-Adrenergic Agonist
Therapeutic Class: Nasal and Ophthalmic Vasoconstrictor
Therapeutic Area: Ophthalmology / Respiratory
Molecule Type: Synthetic Small Molecule
Naphazoline acts primarily as an alpha-adrenergic receptor agonist. Activation of alpha-adrenergic receptors on vascular smooth muscle produces vasoconstriction.
Its pharmacological effects include:
Naphazoline API is used in pharmaceutical development for:
Naphazoline is particularly relevant to ophthalmic formulations, where its local vasoconstrictor activity can temporarily reduce redness caused by superficial vascular dilation.
Naphazoline is also used in nasal decongestant formulations. Its alpha-adrenergic activity causes constriction of blood vessels in the nasal mucosa, helping reduce swelling and congestion.
Naphazoline is a crystalline solid. The physical appearance, particle characteristics and other material properties should be controlled according to the applicable pharmaceutical API specification.
A controlled Naphazoline API manufacturing process may involve:
Typical Naphazoline API quality testing may include:
Store Naphazoline API in a tightly closed container under controlled pharmaceutical storage conditions, protected from excessive moisture, heat and direct light. Final storage conditions should follow validated stability data and the approved API specification.
Naphazoline is relevant to research involving:
| Parameter | Specification |
|---|---|
| Appearance | White crystalline powder or crystals |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.5% |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 2.0% |
| Water Content | NMT 1.0% |
| Melting Point | Approximately 115–120°C |