Mobile phase, Dilution solvent, Standard preparation, Resolution solution, and Chromatographic system— Prepare as directed in the Assay under Phenylephrine Hydrochloride Nasal Jelly.

Assay preparation— Transfer an accurately measured volume of Ophthalmic Solution, equivalent to about 10 mg of phenylephrine hydrochloride, to a 100-mL volumetric flask. Dilute with Dilution solvent to volume, and mix.

Procedure— Separately inject equal volumes (about 20 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C9H13NO2·HCl in each mL of Ophthalmic Solution taken by the formula: in which C is the concentration, in mg per mL, of USP Phenylephrine Hydrochloride RS in the Standard preparation, V is the volume, in mL, of Ophthalmic Solution taken, and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.