Packaging and storage—
Preserve in single-unit double-ended glass ampuls or in low-density polyethylene ampuls.
Labeling—
The label indicates that the Inhalation Solution is not to be used if it contains a precipitate.
Identification—
The UVabsorption spectrum of the
Assay preparationprepared as directed in the
Assayexhibits maxima and minima at the same wavelengths as that of a similar solution of
USP Cromolyn Sodium RS,concomitantly measured.
Related compounds—
Apply 10-µLportions of Inhalation Solution and Standard solutions of
USP Cromolyn Sodium RSin a mixture of water,stabilizer-free tetrahydrofuran,and acetone (6:4:1)containing 10mg per mL(
Standard solution A)and 0.1mg per mL(
Standard solution B)to a suitable thin-layer chromatographic plate (see
Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Allow the spots to dry,and develop the chromatogram in a solvent system consisting of a mixture of chloroform,methanol,and glacial acetic acid (9:9:2)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,and allow the solvent to evaporate.Locate the spots on the plate by viewing under short-wavelength UVlight:the
RFvalue of the principal spot obtained from the Inhalation Solution corresponds to that obtained from
Standard solution A.Any spot in the chromatogram obtained from the Inhalation Solution moving ahead of the principal spot is not more intense than the spot in the chromatogram obtained from
Standard solution B(1.0%).
Assay—
pH7.4Sodium phosphate buffer
and
Standard preparation—Prepare as directed in the
Assayunder
Cromolyn Sodium.
Assay preparation—
Dilute with water an accurately measured volume of Inhalation Solution,equivalent to about 25mg of cromolyn sodium,to obtain a solution having a concentration of about 250µg per mL.Pipet 10mLof this solution into a 100-mLvolumetric flask,add 1mLof pH7.4Sodium phosphate buffer,dilute with water to volume,and mix.
Procedure—
Concomitantly determine the absorbances of the
Standard preparationand the
Assay preparationin 1-cm cells at the wavelength of maximum absorbance at about 326nm,with a suitable spectrophotometer,using a 1in 100aqueous solution of
pH7.4Sodium phosphate bufferas the blank.Calculate the quantity,in mg,of C
23H
14Na
2O
11in each mLof the Inhalation Solution taken by the formula:
(C/V)(AU/AS),
in which
Cis the concentration,in µg per mL,of
USP Cromolyn Sodium RSin the
Standard preparation;Vis the volume,in mL,of Inhalation Solution taken;and
AUand
ASare the absorbances of the solutions obtained from the
Assay preparationand the
Standard preparation,respectively.