Oxymetazoline is a synthetic imidazoline derivative with potent alpha-adrenergic activity and is commonly used in pharmaceutical formulations as Oxymetazoline Hydrochloride. The hydrochloride salt is the established pharmaceutical form and is widely incorporated into nasal and ophthalmic preparations because of its vasoconstrictor properties. Oxymetazoline Hydrochloride has the molecular formula C₁₆H₂₄N₂O·HCl, molecular weight 296.84 g/mol, and CAS Number 2315-02-8.
As an alpha-adrenergic agonist, oxymetazoline produces localized vasoconstriction when applied to nasal or ocular tissues. This pharmacological activity makes it an important active pharmaceutical ingredient for products intended to reduce nasal and conjunctival congestion. PubChem identifies oxymetazoline hydrochloride as a direct-acting sympathomimetic, vasoconstrictor and nasal decongestant.
Oxymetazoline Hydrochloride is generally described as a white to practically off-white crystalline material. It is readily soluble in water and has also been reported to be soluble in alcohol. The compound is hygroscopic, making suitable packaging and controlled storage important for maintaining pharmaceutical quality.
The API has a molecular weight of approximately 296.84 g/mol and is identified by IR spectroscopy, chromatographic retention time and chloride identification testing in the current USP-NF monograph. The USP monograph specifies an assay range of 98.5% to 101.5% calculated on the dried basis.
Oxymetazoline Hydrochloride is primarily associated with pharmaceutical formulations for localized vasoconstrictor activity. Its established applications include:
The pharmacological action results primarily from stimulation of alpha-adrenergic receptors, producing constriction of small blood vessels in the administered area.
Quality control is particularly important for Oxymetazoline Hydrochloride because pharmaceutical-grade material must comply with identity, assay, impurity, moisture and physical-quality requirements.
The current USP-NF monograph defines Oxymetazoline Hydrochloride at 98.5–101.5% on the dried basis. Identification includes infrared spectroscopy, chromatographic retention-time comparison and chloride testing. The USP assay uses liquid chromatography with UV detection at 280 nm, an L9 column measuring 4.6 mm × 25 cm, a flow rate of 1 mL/min, and an injection volume of 20 µL. System suitability includes a tailing factor of NMT 2.0 and relative standard deviation of NMT 0.55% for five replicate injections.
For organic impurities, the USP method uses liquid chromatography with UV detection at 220 nm. Oxymetazoline Related Compound A has a limit of NMT 0.15%, any individual unspecified impurity is limited to NMT 0.10%, and total impurities are limited to NMT 0.5%. Peaks below 0.05% are disregarded under the monograph procedure.
The API specification can include identity, assay, loss on drying, residue on ignition, pH, organic impurities and other quality parameters. The current USP monograph specifies:
The USP LOD test is performed by drying at 105°C for 3 hours, while the pH test uses a 50 mg/mL aqueous solution.
Oxymetazoline Hydrochloride should be stored in tight containers as specified by the USP monograph. Proper moisture protection is particularly relevant because the material is described as hygroscopic. Packaging should therefore protect the API from excessive humidity and environmental exposure.
Oxymetazoline Hydrochloride provides pharmaceutical manufacturers with a well-characterized alpha-adrenergic active ingredient suitable for localized nasal and ophthalmic formulations. Its established pharmacological profile, recognized pharmacopoeial status and defined impurity controls make it an important API for regulated pharmaceutical development.
For pharmaceutical manufacturing applications, analytical testing should be performed against the applicable pharmacopoeial monograph and the customer's approved specification. The USP monograph provides defined acceptance criteria for assay, organic impurities, pH, loss on drying and residue on ignition.
Oxymetazoline API manufacturing requires controlled processing, appropriate analytical testing and suitable pharmaceutical-quality systems. Bulk Oxymetazoline Hydrochloride intended for pharmaceutical use should be evaluated for identity, assay, impurity profile, moisture and other applicable quality attributes before release.
The API is identified by CAS 2315-02-8, with C₁₆H₂₄N₂O·HCl as its molecular formula and 296.84 g/mol molecular weight.
Oxymetazoline Hydrochloride is therefore a relevant pharmaceutical ingredient for manufacturers developing nasal decongestant and ophthalmic formulations. A well-controlled API specification aligned with recognized pharmacopoeial requirements helps support consistency, analytical compliance and reliable downstream formulation development.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.5–101.5% on dried basis |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.1% |
| Heavy Metals | NMT 10 ppm |
| pH (1% Solution) | 4.0–6.5 |
| Total Impurities | NMT 0.5% |
| Melting Point | About 300–303°C |