Chloramphenicol and Polymyxin B Sulfate Ophthalmic Ointment
» Chloramphenicol and Polymyxin B Sulfate Ophthalmic Ointment contains not less than 90.0 percent and not more than 120.0 percent of the labeled amount of chloramphenicol (C11H12Cl2N2O5) and not less than 90.0 percent and not more than 125.0 percent of the labeled amount of polymyxin B.
Packaging and storage Preserve in collapsible ophthalmic ointment tubes.
USP Reference standards 11
USP Polymyxin B Sulfate RS
Identification The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation as obtained in the Assay for chloramphenicol.
Sterility 71: meets the requirements.
Metal particles It meets the requirements of the test for Metal Particles in Ophthalmic Ointments 751.
Assay for chloramphenicol
Mobile phase and Chromatographic systemProceed as directed in the Assay under Chloramphenicol.
Standard preparation Proceed as directed for Standard preparation in the Assay under Chloramphenicol Ophthalmic Ointment.
Assay preparation Using Ophthalmic Ointment, proceed as directed for Assay preparation in the Assay under Chloramphenicol Ophthalmic Ointment.
Procedure Proceed as directed for Procedure in the Assay under Chloramphenicol. Calculate the quantity, in mg, of C11H12Cl2N2O5 in the portion of Ophthalmic Ointment taken by the formula:
0.25C(rU / rS)in which the terms are as defined therein.
Assay for polymyxin Proceed as directed for polymyxin under AntibioticsMicrobial Assays 81, using an accurately weighed portion of Ophthalmic Ointment, equivalent to about 5000 Polymyxin B Units, shaken in a separator containing about 50 mL of ether and extracted with four 20-mL portions of Buffer No. 6. Combine the aqueous extracts in a 100-mL volumetric flask, dilute with Buffer No. 6 to volume, and mix. Dilute an accurately measured portion of this solution quantitatively with Buffer No. 6 to obtain a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard.
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USP35NF30 Page 2611