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 90.0 percent and not more than 130.0 percent of the labeled amounts of neomycin and polymyxin B, and not less than 90.0 percent and not more than 110.0 percent 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.
USP Reference standards 11
USP Neomycin Sulfate RS
USP Polymyxin B Sulfate RS
Identification Transfer a quantity of Ophthalmic Suspension, equivalent to about 2.5 mg of dexamethasone, to a suitable test tube, add 5 mL of chloroform, mix, and centrifuge. Apply 25 µL of the lower chloroform layer and 25 µL of a Standard solution of USP Dexamethasone RS in chloroform containing 500 µg per mL to a suitable thin-layer chromatographic plate (see Chromatography 621) 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 UV light: the RF value of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.
Sterility 71 It meets the requirements when tested as directed for Membrane Filtration under Test for Sterility of the Product to be Examined.
pH 791: between 3.5 and 6.0.
Assay for neomycin Proceed as directed for neomycin under AntibioticsMicrobial Assays 81, using an accurately measured volume of Ophthalmic Suspension, freshly mixed and free from air bubbles, diluted quantitatively and stepwise with Buffer No. 3 to yield a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard.
Assay for polymyxin B Proceed as directed for polymyxin B under AntibioticsMicrobial Assays 81, using an accurately measured volume of Ophthalmic Suspension, freshly mixed and free from air bubbles, diluted quantitatively and stepwise with Buffer No. 6 to yield a Test Dilution having 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 systemProceed as directed in the Assay for dexamethasone under Neomycin and Polymyxin B Sulfates and Dexamethasone Ophthalmic Ointment.
Standard preparation Dissolve an accurately weighed quantity of USP Dexamethasone RS in Mobile phase to obtain a solution having a known concentration of about 0.12 mg per mL.
Assay preparation Dilute an accurately measured volume of freshly mixed Ophthalmic Suspension quantitatively with Mobile phase to obtain a solution containing about 0.12 mg of dexamethasone per mL.
Procedure Proceed as directed for Procedure in the Assay for dexamethasone under Neomycin and Polymyxin B Sulfates and Dexamethasone Ophthalmic Ointment. Calculate the quantity, in mg per mL, of C22H29FO5 in the Ophthalmic Suspension taken by the formula:
(CL / D)(rU / rS)in which L is the labeled quantity, in mg per mL, of dexamethasone in the Ophthalmic Suspension, D is the concentration, in mg per mL, of dexamethasone in the Assay preparation based on the labeled quantity in the Ophthalmic Suspension and the extent of dilution, and the other terms are as defined therein.
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USP35NF30 Page 4026