Naphazoline Hydrochloride Ophthalmic Solution
» Naphazoline Hydrochloride Ophthalmic Solution is a sterile, buffered solution of Naphazoline Hydrochloride in water adjusted to a suitable tonicity. It contains not less than 90.0 percent and not more than 115.0 percent of the labeled amount of naphazoline hydrochloride (C14H14N2·HCl). It contains a suitable preservative.
Packaging and storage Preserve in tight containers.
USP Reference standards 11
Identification Place in a separator a volume of Ophthalmic Solution, equivalent to about 25 mg of naphazoline hydrochloride, add 5 mL of 1 N sodium hydroxide, saturate with sodium chloride, and extract with two 25-mL portions of ether. Wash the ether solution with 5 mL of water, pass the ether through a small paper filter, evaporate the filtrate to about 5 mL, transfer the residual solution to a 10- to 15-mL beaker, allow to evaporate spontaneously, and dry the residue at 80 for 1 hour: the naphazoline so obtained melts between 115 and 120 when determined as directed for Class Ia under Melting Range or Temperature 741.
Sterility 71: meets the requirements.
pH 791: between 5.5 and 7.0.
Phosphate buffer Transfer 3 g of monobasic potassium phosphate to a 1-L volumetric flask, dissolve in 1000 mL of water and 3 mL of triethylamine, and mix. Adjust with phosphoric acid to a pH of 3, and mix.
Mobile phase Prepare a filtered and degassed mixture of Phosphate buffer and acetonitrile (80:20). Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard preparation Dissolve an accurately weighed quantity of USP Naphazoline Hydrochloride RS in water, and dilute quantitatively, and stepwise if necessary, with Mobile phase to obtain a solution having a known concentration of about 0.05 mg per mL.
Assay preparation Transfer an accurately measured volume of Ophthalmic Solution, equivalent to about 5.0 mg of naphazoline hydrochloride, to a 100-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix.
Chromatographic system (see Chromatography 621) The liquid chromatograph is equipped with a 285-nm detector and a 4.6-mm × 15-cm column that contains packing L10. The flow rate is about 1.5 mL per minute. The column temperature is maintained at 40. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the column efficiency is not less than 5000 theoretical plates; the tailing factor is not more than 2.0; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure Separately inject equal volumes (about 10 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 C14H14N2·HCl in the portion of Ophthalmic Solution taken by the formula:
100C (rU / rS)in which C is the concentration, in mg per mL, of USP Naphazoline Hydrochloride RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 3993Pharmacopeial Forum: Volume No. 33(5) Page 926