Neomycin Sulfate and Prednisolone Sodium Phosphate Ophthalmic Ointment
» Neomycin Sulfate and Prednisolone Sodium Phosphate Ophthalmic Ointment is a sterile ointment containing Neomycin Sulfate and Prednisolone Sodium Phosphate. It contains the equivalent of not less than 90.0 percent and not more than 135.0 percent of the labeled amount of neomycin, and the equivalent of not less than 90.0 percent and not more than 115.0 percent of the labeled amount of prednisolone phosphate (C21H29O8P).
noteWhere Neomycin Sulfate and Prednisolone Sodium Phosphate Ophthalmic Ointment is prescribed without reference to the quantity of neomycin or prednisolone phosphate contained therein, a product containing 3.5 mg of neomycin and 2.5 mg of prednisolone phosphate per g shall be dispensed.
Packaging and storage Preserve in collapsible ophthalmic ointment tubes.
B: Shake a quantity of Ophthalmic Ointment, equivalent to about 40 mg of prednisolone phosphate, with 25 mL of sodium chloride solution (1 in 20) and 25 mL of methylene chloride, for 2 minutes. Transfer the methylene chloride layer to a second separator containing 15 mL of sodium chloride (1 in 20). Shake for 1 minute, and discard the methylene chloride layer. Repeat the operation with a second portion of 25 mL of methylene chloride. Combine the aqueous phase from the second separator with the aqueous phase of the first separator. Add 10 mL of Alkaline phosphatase solution, prepared as directed in the Assay for prednisolone phosphate, and add 50 mL of methylene chloride. Insert the stopper, and allow to stand, with occasional gentle inversion (about once every 15 minutes), for 2 hours. Filter the methylene chloride layer through a dry paper, and evaporate 25 mL of the filtrate to dryness: the residue so obtained responds to Identification test A under Prednisolone.
Sterility 71: meets the requirements.
Minimum fill 755: meets the requirements.
Water, Method I 921: not more than 1.0%, 20 mL of a mixture of toluene and methanol (7:3) being used in place of methanol in the titration vessel.
Metal particles It meets the requirements of the test for Metal Particles in Ophthalmic Ointments 751.
Assay for neomycin Proceed as directed under AntibioticsMicrobial Assays 81, using an accurately weighed portion of Ophthalmic Ointment shaken in a separator with about 50 mL of ether, and extracted with four 20-mL portions of Buffer No. 3. Combine the aqueous extracts, and dilute with Buffer No. 3 to an appropriate volume to obtain a stock solution. Dilute this stock solution quantitatively and stepwise with Buffer No. 3 to obtain a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard.
Assay for prednisolone phosphate
Alkaline phosphatase solution Prepare as directed in the Assay under Dexamethasone Sodium Phosphate Injection.
Standard preparation Prepare as directed for Standard Preparation under Assay for Steroids 351, using USP Prednisolone RS.
Assay preparation Transfer an accurately weighed portion of Ophthalmic Ointment, equivalent to about 3 mg of prednisolone phosphate, to a 125-mL separator. Add 25 mL of sodium chloride solution (1 in 20) and 25 mL of methylene chloride, and shake for not less than 2 minutes to disperse the assay specimen. Transfer the methylene chloride layer to a second separator containing 15 mL of sodium chloride solution (1 in 20). Shake for 1 minute, and discard the methylene chloride layer. Repeat the operation with a second portion of 25 mL of methylene chloride. Transfer the aqueous phases from both separators to a 50-mL volumetric flask, rinsing the first separator with the aqueous phase of the second separator. Rinse both separators with the same 5 mL of sodium chloride solution (1 in 20), and add the rinsing to the volumetric flask. Add sodium chloride solution (1 in 20) to volume, and mix.
Pipet 5 mL of the resulting solution into a 125-mL separator, add 8.0 mL of Alkaline phosphatase solution, mix, and allow to stand for 2 hours. Extract the solution with two 25-mL portions of methylene chloride, filtering the extracts through methylene chloride-washed cotton into a small beaker. Evaporate the methylene chloride on a steam bath nearly to dryness, then evaporate with the aid of a current of air to dryness. Dissolve the residue in 25.0 mL of alcohol.
Prepare a blank by evaporating 50 mL of methylene chloride to dryness and dissolving the residue in 25 mL of alcohol.
Procedure Pipet 20 mL each of the Assay preparation, the Standard preparation, and the blank solution into separate glass-stoppered flasks, and proceed as directed for Procedure under Assay for Steroids 351, beginning with add 2.0 mL of a solution prepared by dissolving 50 mg of blue tetrazolium. Calculate the quantity, in mg, of prednisolone phosphate (C21H29O8P) in the portion of Ophthalmic Ointment taken by the formula:
0.25C(AU / AS)(440.43 / 360.45)in which C is the concentration, in µg per mL, of USP Prednisolone RS in the Standard preparation, AU and AS are the absorbances of the solutions from the Assay preparation and the Standard preparation, respectively, and 440.43 and 360.45 are the molecular weights of prednisolone phosphate and prednisolone, respectively.
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USP32NF27 Page 3068