Neomycin and Polymyxin B Sulfates and Dexamethasone Ophthalmic Suspension
»Neomycin and Polymyxin B Sulfates and Dexamethasone Ophthalmic Suspension contains the equivalent of not less than 90.0percent and not more than 130.0percent of the labeled amounts of neomycin and polymyxin B,and not less than 90.0percent and not more than 110.0percent of the labeled amount of dexamethasone.It may contain one or more suitable buffers,stabilizers,preservatives,and suspending agents.
Packaging and storage— Preserve in tight,light-resistant containers in a cool place or at controlled room temperature.The containers or individual cartons are sealed and tamper-proof so that sterility is assured at time of first use.
Identification— Transfer a quantity of Ophthalmic Suspension,equivalent to about 2.5mg of dexamethasone,to a suitable test tube,add 5mLof chloroform,mix,and centrifuge.Apply 25µLof the lower chloroform layer and 25µLof a Standard solution of USP Dexamethasone RSin chloroform containing 500µg per mLto a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel.Allow the spots to dry,and develop the chromatogram in a solvent system consisting of a mixture of chloroform and diethylamine (2:1)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 examination under short-wavelength UVlight:the RFvalue of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.
Sterility á71ñ— It meets the requirements when tested as directed for Membrane Filtration underTest for Sterility of the Product to be Examined.
pHá791ñ: between 3.5and 6.0.
Assay for neomycin— Proceed as directed for neomycin under Antibiotics—Microbial Assays á81ñ,using an accurately measured volume of Ophthalmic Suspension,freshly mixed and free from air bubbles,diluted quantitatively and stepwise with Buffer No.3to yield a Test Dilutionhaving a concentration assumed to be equal to the median dose level of the Standard.
Assay for polymyxin B— Proceed as directed for polymyxin Bunder Antibiotics—Microbial Assays á81ñ,using an accurately measured volume of Ophthalmic Suspension,freshly mixed and free from air bubbles,diluted quantitatively and stepwise with Buffer No.6to yield a Test Dilutionhaving a concentration assumed to be equal to the median dose level of the Standard.Add to each test dilution of the Standard a quantity of USP Neomycin Sulfate RS,dissolved in Buffer No.6,to obtain the same concentration of neomycin as is present in the Test Dilution.
Assay for dexamethasone—
Mobile phase and Chromatographic system—Proceed as directed in the Assay for dexamethasoneunder Neomycin and Polymyxin B Sulfates and Dexamethasone Ophthalmic Ointment.
Standard preparation— Dissolve an accurately weighed quantity of USP Dexamethasone RSin Mobile phaseto obtain a solution having a known concentration of about 0.12mg per mL.
Assay preparation— Dilute an accurately measured volume of freshly mixed Ophthalmic Suspension quantitatively with Mobile phaseto obtain a solution containing about 0.12mg of dexamethasone per mL.
Procedure— Proceed as directed for Procedurein the Assay for dexamethasoneunder Neomycin and Polymyxin B Sulfates and Dexamethasone Ophthalmic Ointment.Calculate the quantity,in mg per mL,of C22H29FO5in the Ophthalmic Suspension taken by the formula:
(CL/D)(rU/rS),
in which Lis the labeled quantity,in mg per mL,of dexamethasone in the Ophthalmic Suspension,Dis the concentration,in mg per mL,of dexamethasone in the Assay preparationbased on the labeled quantity in the Ophthalmic Suspension and the extent of dilution,and the other terms are as defined therein.
Auxiliary Information— Staff Liaison:William W.Wright,Ph.D.,Scientific Fellow
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 1357
Phone Number:1-301-816-8335