Packaging and storage—
Preserve in small, tight containers that are well-filled or otherwise protected from oxidation. Protect from light.
Labeling—
The label indicates that the Inhalation Solution is not to be used if its color is pinkish or darker than slightly yellow or if it contains a precipitate.
Color and clarity—
Standard solution—
Transfer 2.0 mL of 0.100 N iodine VS to a 500-mL volumetric flask, dilute with water to volume, and mix.
Procedure—
Visually examine a portion of the Inhalation Solution (Test solution) in a suitable clear glass test tube against a white background: it is not pinkish and it contains no precipitate. If any yellow color is observed in the Test solution, concomitantly determine the absorbances of the Test solution and the Standard solution in 1-cm cells with a suitable spectrophotometer set at 460 nm: the absorbance of the Test solution does not exceed that of the Standard solution.
Identification—
Dilute the Inhalation Solution with water to obtain a solution containing about 2.5 mg of isoetharine hydrochloride per mL. Apply 10-µL portions of this solution and a solution of
USP Isoetharine Hydrochloride RS containing 2.5 mg per mL to a thin-layer chromatographic plate coated with silica gel mixture. Develop the plate in a mixture consisting of
n-butyl alcohol, water, and formic acid (70:20:10) to a height of 12 to 14 cm above the point of application. Remove the plate, and evaporate the solvents with the aid of warm, circulating air. Examine under short-wavelength UV light. Spray the plate with Folin–Ciocalteu phenol TS, and then expose to ammonia vapor until the isoetharine spots develop an intense blue color: the
RF value and color of the principal spot obtained from the solution under test correspond to those obtained from the
Standard solution.
Assay—
Assay preparation—
Transfer an accurately measured volume of Inhalation Solution, equivalent to about 50 mg of isoetharine hydrochloride, to a 100-mL volumetric flask, dilute with 0.17 N acetic acid solution to volume, and mix.
Procedure—
Proceed as directed for
Procedure in the
Assay under
Isoetharine Hydrochloride. Calculate the quantity, in mg, of C
13H
21NO
3·HCl in each mL of the Inhalation Solution taken by the formula:
0.1(C/V)(hU / hS),
in which
V is the volume, in mL, of Inhalation Solution taken; and
C,
hU, and
hS are as defined therein.
71
:
meets the requirements.