Polymyxin B Sulfate and Hydrocortisone Otic Solution
»Polymyxin B Sulfate and Hydrocortisone Otic Solution is a sterile solution containing not less than 90.0percent and not more than 130.0percent of the labeled amount of polymyxin B,and not less than 90.0percent and not more than 110.0percent of the labeled amount of hydrocortisone (C21H30O5).It may contain one or more suitable buffers and preservatives.
NOTE—Where Polymyxin B Sulfate and Hydrocortisone Otic Solution is prescribed without reference to the quantity of polymyxin Bor hydrocortisone contained therein,a product containing 10,000Polymyxin B Units and 5mg of hydrocortisone per mLshall be dispensed.
Packaging and storage— Preserve in tight,light-resistant containers.
Sterility á71ñ: meets the requirements.
pHá791ñ: between 3.0and 5.0.
Assay for polymyxin— Proceed with Otic Solution as directed under Antibiotics—Microbial Assays á81ñ,using an accurately measured volume of Otic Solution diluted quantitatively with Buffer No.6to yield a Test Dilutionhaving a concentration assumed to be equal to the median dose level of the Standard.
Assay for hydrocortisone—
Mobile phase— Prepare a suitable solution of about 500volumes of methanol,500volumes of water,and 1volume of glacial acetic acid,such that the retention time of hydrocortisone is between 6and 10minutes.
Standard preparation— Dissolve a suitable quantity of USP Hydrocortisone RS,accurately weighed,in a mixture of methanol and water (1:1)to obtain a solution having a known concentration of about 0.15mg per mL.
Assay preparation— Transfer an accurately measured volume of Otic Solution,equivalent to about 15mg of hydrocortisone,to a 100-mLvolumetric flask,dilute with a mixture of methanol and water (1:1)to volume,and mix.
Chromatographic system (see Chromatography á621ñ)—The chromatograph is equipped with a 254-nm detector and a 4-mm ×30-cm column that contains packing L1.The flow rate is about 2mLper minute.Chromatograph five replicate injections of the Standard preparation,and record the peak responses as directed for Procedure:the relative standard deviation is not more than 2.0%.
Procedure— Separately inject equal volumes (about 10µL)of the Standard preparationand the Assay preparationinto the chromatograph by means of a suitable microsyringe or sampling valve,adjusting the specimen size and other operating parameters such that the peak obtained from the Standard preparationis about 0.6full-scale.Record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C21H30O5in each mLof the Otic Solution taken by the formula:
(100C/V)(HU/HS),
in which Cis the concentration,in mg per mL,of USP Hydrocortisone RSin the Standard preparation,Vis the volume,in mL,of the portion of Otic Solution taken,and HUand HSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:William W.Wright,Ph.D.,Scientific Fellow
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 1578
Phone Number:1-301-816-8335
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