Fluorometholone Ophthalmic Suspension
» Fluorometholone Ophthalmic Suspension is a sterile suspension of Fluorometholone in a suitable aqueous medium. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of fluorometholone (C22H29FO4). It may contain suitable stabilizers, buffers, and antimicrobial agents.
Packaging and storage Preserve in tight containers.
USP Reference standards 11
Identification Mix 1 mL of the well-shaken Ophthalmic Suspension with 2 mL of a mixture of methanol and water (3:2) until a solution is obtained. Apply 20-µL portions of this solution and of a Standard solution of USP Fluorometholone RS in the same solvent 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 mixture and previously activated by heating at 80 for 5 minutes. Allow the spots to dry, and develop the chromatogram in a solvent system consisting of methylene chloride and acetone (4:1) until the solvent front has moved not less than 15 cm. Remove the plate from the developing chamber, mark the solvent front, and allow to air-dry. Examine the plate under short-wavelength UV light: the RF value and intensity of the principal spot obtained from the test solution correspond to those obtained from the Standard solution.
Sterility 71: meets the requirements.
pH 791: between 6.0 and 7.5.
Mobile phase Prepare a suitable filtered solution of methanol and water (60:40) such that the retention time of fluorometholone is about 3 minutes.
Standard preparation Using a suitable quantity of USP Fluorometholone RS, accurately weighed, prepare a solution in methanol containing 0.5 mg per mL. Pipet 10 mL of this solution and 5 mL of water into a 50-mL volumetric flask. Dilute with methanol to volume, and mix to obtain a Standard preparation having a known concentration of about 100 µg per mL.
Assay preparation Pipet a volume of well-shaken Ophthalmic Suspension, equivalent to about 5 mg of fluorometholone, into a 50-mL volumetric flask, dilute with methanol to volume, and mix. Pass through a 5-µm membrane filter, and use the clear filtrate.
Chromatographic system (see Chromatography 621)The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm × 25-cm column that contains packing L1. The flow rate is about 2 mL per minute. Chromatograph six 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 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, using a suitable microsyringe or sampling valve, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of fluorometholone (C22H29FO4) in the portion of Ophthalmic Suspension taken by the formula:
0.05C(rU / rS)in which C is the concentration, in µg per mL, of USP Fluorometholone RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 3239