Tetrahydrozoline Hydrochloride Nasal Solution
» Tetrahydrozoline Hydrochloride Nasal Solution is a solution of Tetrahydrozoline Hydrochloride in water adjusted to a suitable tonicity. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of C13H16N2·HCl.
Packaging and storage Preserve in tight containers.
USP Reference standards 11
USP Tetrahydrozoline Hydrochloride RS.
Identification The UV absorption spectrum of the Nasal Solution, diluted with water, if necessary, to a concentration of about 1 in 4000, exhibits maxima and minima at the same wavelengths as that of a similar solution of USP Tetrahydrozoline Hydrochloride RS, concomitantly measured.
Microbial enumeration tests 61 and Tests for specified microorganisms 62 It meets the requirements of the tests for absence of Staphylococcus aureus and Pseudomonas aeruginosa.
pH 791: between 5.3 and 6.5.
Oxidized nitroprusside reagent Dissolve 1.0 g of sodium nitroferricyanide in water to make 10.0 mL (Solution A). Dissolve 1.0 g of potassium ferricyanide in water to make 10.0 mL (Solution B). Transfer 1.0 mL each of Solution A and Solution B to a 100-mL volumetric flask, add 1 mL of sodium hydroxide solution (1 in 10), and allow to stand until the solution changes to a light yellow color (about 20 to 30 minutes). Dilute with water to volume, and mix. Store in a refrigerator or keep in an ice bath, and use within 4 hours.
Standard preparation Dissolve a suitable quantity of USP Tetrahydrozoline Hydrochloride RS, accurately weighed, in water, and dilute quantitatively with water to obtain a solution having a known concentration of about 100 µg per mL.
Assay preparation Transfer an accurately measured volume of Nasal Solution, equivalent to about 10 mg of tetrahydrozoline hydrochloride, to a 100-mL volumetric flask, dilute with water to volume, and mix.
Procedure Transfer 5.0 mL each of the Standard preparation and the Assay preparation to separate glass-stoppered test tubes. Pipet 5 mL of water into a third tube to provide a blank. To each tube add 4.0 mL of Oxidized nitroprusside reagent, mix, and allow to stand at 30 for 15 minutes. Concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 570 nm, with a suitable spectrophotometer, using the blank to set the instrument. Calculate the quantity, in mg, of C13H16N2·HCl in each mL of the Nasal Solution taken by the formula:
0.1(C / V)(AU / AS)in which C is the concentration, in µg per mL, of USP Tetrahydrozoline Hydrochloride RS in the Standard preparation, V is the volume, in mL, of Nasal Solution taken, and AU and AS are the absorbances of the solutions from the Assay preparation and the Standard preparation, respectively.
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USP32NF27 Page 3702