Naphazoline Hydrochloride and Pheniramine Maleate Ophthalmic Solution

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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1 DEFINITION

Naphazoline Hydrochloride and Pheniramine Maleate Ophthalmic Solution is a sterile, buffered solution of Naphazoline Hydrochloride and Pheniramine Maleate in water adjusted to a suitable tonicity. It contains NLT 90.0% and NMT 110.0% of the labeled amount of naphazoline hydrochloride (C₁₄H₁₄N₂ · HCI) and pheniramine maleate (C₁₆H₂₀N₂ · C₄H₄O₄). It contains a suitable preservative.

2 IDENTIFICATION

A. THIN-LAYER CHROMATOGRAPHY

Standard solution A: 1.5 mg/mL of USP Naphazoline Hydrochloride RS in water

Standard solution B: 6.0 mg/mL of USP Pheniramine Maleate RS in water

Sample solution: Equivalent to 0.25 mg/mL of naphazoline hydrochloride and 3 mg/mL of pheniramine maleate in water from Ophthalmic Solution

Chromatographic system

(See Chromatography (621), Thin-layer Chromatography.)

Adsorbent: 0.25-mm layer of silica gel on a 20-cm x 20-cm chromatographic plate

Application volume: 5 µL of Standard solution A, 10 µL of Standard solution B, and 30 µL of the Sample solution

Developing solvent system: Methanol, acetic acid, and water (8:1:1)

Spray reagent: Ninhydrin TS

Analysis

Samples: Standard solution A, Standard solution B, and Sample solution

Allow the spots to dry, then place the plate in a saturated chromatographic chamber, and develop in the Developing solvent system until the solvent front has moved to 1.5 cm from the top of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow to air-dry. Spray with Spray reagent, and place in an oven at 105° to visualize the spots. Both the naphazoline and pheniramine spots are purplish gray in color.

Acceptance criteria: The R_F values of the spots of the Sample solution correspond to those of Standard solution A and Standard solution B.

B. The retention time of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

PROCEDURE

Buffer solution: Dissolve 14.2 g of anhydrous dibasic sodium phosphate and 20 mL of triethylamine in 1900 mL of water. Adjust with phosphoric acid to a pH of 5.6 ± 0.1, and dilute with water to 2000 mL.

Mobile phase: Acetonitrile and Buffer solution (20:80)

Standard stock solution A: 0.75 mg/mL of USP Naphazoline Hydrochloride RS in Mobile phase

Standard stock solution B: 3.00 mg/mL of USP Pheniramine Maleate RS in Mobile phase

Standard solution: 0.03 mg/mL of naphazoline hydrochloride and 0.36 mg/mL of pheniramine maleate in Mobile phase prepared as follows. Transfer 1.0 mL of Standard stock solution A and 3.0 mL of Standard stock solution B to a 25-mL volumetric flask. Dilute with Mobile phase to volume.

Sample solution: Transfer a volume of Ophthalmic Solution, equivalent to 0.75 mg of naphazoline hydrochloride and 9.0 mg of pheniramine maleate, to a 25-mL volumetric flask. Dilute with Mobile phase to volume.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 270 nm

Column: 4.6-mm x 15-cm; packing L7

Flow rate: 1.5 mL/min

Injection volume: 25 µL

System suitability

Sample: Standard solution

Suitability requirements

Resolution: NLT 2 between the naphazoline and pheniramine peaks

Column efficiency: NLT 750 theoretical plates for the naphazoline and pheniramine peaks

Tailing factor: NMT 2.5 for pheniramine

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of naphazoline hydrochloride (C₁₄H₁₄N₂ · HCI) in the portion of Ophthalmic Solution taken:

                         Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of naphazoline from the Sample solution

r_S = peak response of naphazoline from the Standard solution

C_S = concentration of USP Naphazoline Hydrochloride RS in the Standard solution (mg/mL)

C_U = nominal concentration of naphazoline hydrochloride in the Sample solution (mg/mL)

Calculate the percentage of the labeled amount of pheniramine maleate (C₁₆H₂₀N₂ · C₄H₄O₄) in the portion of Ophthalmic Solution taken:

                         Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of pheniramine from the Sample solution

r_S = peak response of pheniramine from the Standard solution 

C_S = concentration of USP Pheniramine Maleate RS in the Standard solution (mg/mL)

C_U = nominal concentration of pheniramine maleate in the Sample solution (mg/mL)

Acceptance criteria

Naphazoline hydrochloride: 90.0%-110.0%

Pheniramine maleate: 90.0%-110.0%

4 SPECIFIC TESTS

PH (791): 5.7-6.3

STERILITY TESTS (71); It meets the requirements when tested as directed in Test for Sterility of the Product to Be Examined, Membrane Filtration.

5 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight containers, and store at a temperature between 20° and 25°, protected from light.

USP REFERENCE STANDARDS (11)

USP Naphazoline Hydrochloride RS

USP Pheniramine Maleate RS