Silver Sulfadiazine Cream
» Silver Sulfadiazine Cream contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of C10H9AgN4O2S.
Packaging and storage Preserve in collapsible tubes or in tight, light-resistant containers.
Identification Dissolve about 35 mg of USP Sulfadiazine RS in 4 mL of ammonium hydroxide, add 16 mL of methanol, and mix to obtain the Standard solution. Transfer a quantity of Cream, equivalent to about 50 mg of silver sulfadiazine, to a stoppered, 50-mL conical flask, add 4 mL of ammonium hydroxide, and mix until a smooth paste has been obtained. Add 16 mL of methanol, shake for 5 minutes, and filter to obtain the test solution: the test solution so obtained responds to the Thin-layer Chromatographic Identification Test 201, a mixture of chloroform, methanol, and ammonium hydroxide (7:4:1) being used as the developing solvent. [notePrepare the developing solvent by first mixing the chloroform and methanol, and then adding the ammonium hydroxide.]
Microbial enumeration tests 61 and Tests for specified microorganisms 62 It meets the requirements of the tests for absence of Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella species, and Escherichia coli and the total count does not exceed 23 cfu per g. It meets also the requirements for Total Combined Molds and Yeasts Count, fewer than 10 cfu per g being found.
Minimum fill 755: meets the requirements.
pH 791: between 4.0 and 7.0, determined in the supernatant obtained from a 1 in 20 mixture of the Cream in water.
Mobile phase and Diluting solutionProceed as directed in the Assay under Silver Sulfadiazine.
Internal standard solution Dissolve an accurately weighed quantity of sulfamerazine in Diluting solution, and dilute quantitatively, and stepwise if necessary, with Diluting solution to obtain a solution having a known concentration of about 2 mg per mL.
Standard stock solution Dissolve an accurately weighed quantity of USP Silver Sulfadiazine RS in Diluting solution to obtain a solution having a known concentration of about 1 mg per mL.
Standard preparation 1 Pipet 10.0 mL of the Standard stock solution into a 50-mL test tube. Add 20 mL of alcohol and 5.0 mL of the Internal standard solution, and mix.
Standard preparation 2 Pipet 2.0 mL of Standard preparation 1 into a 50-mL test tube. Add 40 mL of Mobile phase, and mix.
Assay preparation Transfer an accurately weighed portion of Cream, equivalent to about 10 mg of silver sulfadiazine, to a 50-mL round-bottom centrifuge tube. Add about 30 mL of methanol, tightly seal the tube with a cap containing an inert liner, and mix, using a vortex mixer, for about 15 seconds. Centrifuge for 15 minutes. Aspirate, and discard the methanol. [noteCare should be taken to avoid aspirating any of the residue.] Transfer 5.0 mL of the Internal standard solution into the tube, and add 20 mL of alcohol. Replace the cap, and mix. Heat in a water bath at 60, with periodic mixing, for 15 minutes to melt and disperse the Cream. While the mixture is still hot, transfer 10.0 mL of Diluting solution to the tube, mix, and cool to room temperature. Transfer 2.0 mL of this solution to another tube, add 40 mL of Mobile phase, mix, and filter.
Chromatographic system Proceed as directed in the Assay under Silver Sulfadiazine. Chromatograph replicate injections of Standard preparation 2, and record the peak responses as directed for Procedure: the resolution, R, between sulfadiazine and sulfamerazine is not less than 2.0, and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure Separately inject equal volumes (about 10 µL) of Standard preparation 2 and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of silver sulfadiazine in the portion of Cream taken by the formula:
10C(RU / RS)in which C is the concentration, in mg per mL, of USP Silver Sulfadiazine RS in the Standard stock solution; and RU and RS are the relative peak response ratios obtained from the Assay preparation and Standard preparation 2, respectively.
Auxiliary Information Please check for your question in the FAQs before contacting USP.Chromatographic Column
USP32NF27 Page 3620
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.