Cefazolin Ophthalmic Solution
» Cefazolin Ophthalmic Solution contains an amount of Cefazolin Sodium equivalent to not less than 29.7 mg and not more than 36.3 mg of cefazolin (C14H14N8O4S3) in 10.0 mL of Ophthalmic Solution. Use Cefazolin Sodium or Cefazolin for Injection that contains the designated amount of cefazolin, and prepare the Ophthalmic Solution as follows (see Pharmaceutical CompoundingNonsterile Preparations 795):
Dissolve accurately weighed quantities of Cefazolin Sodium and Thimerosal in Sodium Chloride Injection (0.9%), and dilute quantitatively, and stepwise if necessary, with Sodium Chloride Injection (0.9%) to obtain a solution containing, in each mL, 3.5 mg of Cefazolin Sodium and 0.02 mg of Thimerosal. Filter a 10.0-mL portion of the resulting solution to produce a clear and sterile Ophthalmic Solution. If Cefazolin for Injection is used, prepare the Ophthalmic Solution as follows. Dissolve an accurately weighed quantity of Thimerosal in Sodium Chloride Injection (0.9%), and dilute quantitatively, and stepwise if necessary, with Sodium Chloride Injection (0.9%) to obtain a solution containing 0.3 mg of Thimerosal per mL. Add 9.8 mL of the resulting solution to a vial of Cefazolin for Injection, containing 500 mg of cefazolin, and mix to obtain a stock solution. Transfer 3.3 mL of the stock solution to a 50-mL volumetric flask, dilute with Sodium Chloride Injection (0.9%) to volume, and mix. Filter a 10.0-mL portion of the resulting solution to produce a clear and sterile Ophthalmic Solution.
Packaging and storage
Preserve in tight, sterile ophthalmic containers. Store in a refrigerator.
Labeling
Label it to state that it is intended for use in the eye and is not to be used if a precipitate is present.
Sterility
See Sterility under Pharmaceutical CompoundingNonsterile Preparations 795.
pH 791:
between 4.5 and 6.0.
Beyond-use date:
5 days after the date on which it was compounded.
Compliance assay
pH 3.6 Buffer
Transfer about 0.900 g of anhydrous dibasic sodium phosphate and about 1.298 g of citric acid monohydrate to a 1-liter volumetric flask, dissolve in and dilute with water to volume, and mix.
pH 7.0 Buffer
Transfer about 5.68 g of anhydrous dibasic sodium phosphate and about 3.63 g of monobasic potassium phosphate to a 1-liter volumetric flask, dissolve in and dilute with water to volume, and mix.
Solution A
Combine 900 mL of pH 3.6 Buffer and 100 mL of acetonitrile in a suitable container. Pass the resulting solution through a filter having a 5-µm or finer porosity, and degas.
Solution B
Combine 200 mL of pH 3.6 Buffer and 800 mL of acetonitrile in a suitable container. Pass the resulting solution through a filter having a 5-µm or finer porosity, and degas.
Mobile phase
Use variable mixtures of Solution A and Solution B as directed for Chromatographic system. Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard preparation
Using low-actinic volumetric glassware, dissolve an accurately weighed quantity of USP Cefazolin RS in pH 7.0 Buffer, and dilute quantitatively, and stepwise if necessary, with pH 7.0 Buffer to obtain a solution having a known concentration of about 0.32 mg per mL. Maintain at 4 prior to injection.
Assay preparation
Transfer 1.0 mL of Ophthalmic Solution to a 10-mL low-actinic volumetric flask, dilute with pH 7.0 Buffer to volume, and mix. Maintain at 4 prior to injection.
Chromatographic system (see Chromatography 621)
The liquid chromatograph is equipped with a 273-nm detector and a 3.9-mm × 30-cm column that contains 10-µm packing L1. The flow rate is about 2 mL per minute and the column temperature is maintained at 25. The chromatograph is programmed as follows.
Procedure
Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of cefazolin (C14H14N8O4S3) in 10 mL of Ophthalmic Solution taken by the formula:
100C(rU / rS)
in which C is the concentration, in mg per mL, of USP Cefazolin RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information
Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 2537
Pharmacopeial Forum: Volume No. 28(2) Page 261
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