Mobile phase— Prepare a mixture of methanol and water (1:1)containing 1.1g of sodium 1-octanesulfonate per liter,adjust with phosphoric acid to a pHof 3.0,filter,and degas.Make adjustments to the methanol and water ratio,if necessary (see System Suitabilityunder Chromatography á621ñ).

Dilution solvent— Prepare a mixture of methanol and water (1:1),and adjust with phosphoric acid to a pHof 3.0.

Standard preparation— Dissolve an accurately weighed quantity of USP Phenylephrine Hydrochloride RSin Dilution solventto obtain a Stock standard solution having a known concentration of about 2mg per mL.Dilute an accurately measured volume of this solution with Dilution solventto obtain the Standard preparationhaving a known concentration of about 0.1mg per mL.

Assay preparation— Transfer an accurately weighed amount of Nasal Jelly,equivalent to about 10mg of phenylephrine hydrochloride,to a 100-mLvolumetric flask.Dilute with Dilution solventto volume,and mix.

Resolution solution— Transfer 5.0mLof Stock standard solution to a 100-mLvolumetric flask,add 10mg of USP Epinephrine Bitartrate RS,dilute with Dilution solventto volume,and mix.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 280-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The flow rate is about 1mLper minute.Chromatograph the Resolution solution:the resolution,R,is not less than 1.5,and the tailing factor for the phenylephrine peak is not more than 2.0.Chromatograph replicate injections of the Standard preparation:the relative standard deviation is not more than 2.0%.

Procedure— Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C9H13NO2·HCl in the portion of Nasal Jelly taken by the formula: in which Cis the concentration,in mg per mL,of USP Phenylephrine Hydrochloride RSin the Standard preparation,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.