Cromolyn Sodium Inhalation Solution
»Cromolyn Sodium Inhalation Solution is a sterile,aqueous solution of Cromolyn Sodium.It contains not less than 90.0percent and not more than 110.0percent of the labeled amount of C23H14Na2O11.
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.
Sterility á71ñ: meets the requirements.
Uniformity of dosage units á905ñ: meets the requirements.
pHá791ñ: between 4.0and 7.0.
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 C23H14Na2O11in 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.
Auxiliary Information— Staff Liaison:Kahkashan Zaidi,Ph.D.,Senior Scientific Associate
Expert Committee:(AER)Aerosols
USP28–NF23Page 550
Phone Number:1-301-816-8269