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and 30.
621
) containing 200 mL of ether, place a beaker containing 25 mL of ammonium hydroxide. Cover the chamber, and allow to equilibrate for 2 hours. Place a portion of Cream, equivalent to about 5 mg of clotrimazole, in a 50-mL centrifuge tube, add 5 mL of chloroform, mix, and centrifuge to obtain a clear test solution. Apply 20 µL of the lower, chloroform phase and 20 µL of a solution of USP Clotrimazole RS in chloroform containing 1 mg per mL to a suitable thin-layer chromatographic plate (see Chromatography 621), coated with a 0.25-mm layer of chromatographic silica gel mixture. Develop the chromatogram until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow the solvent to evaporate. Locate the spots on the plate by examination under short-wavelength UV light: the RF value of the principal spot from the test solution corresponds to that obtained from the Standard solution. Dissolve 3 g of bismuth subnitrate and 30 g of potassium iodide in 10 mL of dilute hydrochloric acid (1 in 4), dilute with water to 100 mL, mix, and prepare a spray reagent by diluting 10 mL of this solution and 5 mL of dilute hydrochloric acid (1 in 4) with water to 200 mL, and mixing. Spray the plate evenly with this spray reagent: the principal spots from the test solution and the Standard solution are orange.
467:
meets the requirements.
in a water bath for 5 minutes, with occasional shaking. Remove the tube from the bath, and shake vigorously for 5 minutes. Cool in a methanol-ice bath for 15 minutes, and promptly centrifuge. Transfer the supernatant to a test tube. Add 10.0 mL of dehydrated alcohol to the residue in the centrifuge tube, and repeat the extraction starting with “heat at 50 in a water bath”. Transfer the supernatant to the test tube containing the supernatant from the first extraction, and mix. Use this solution as the Assay preparation.
621)—
The liquid chromatograph is equipped with a 254-nm detector and a 2.1-mm × 6-cm guard column that contains 10-µm packing L7 and a 3.9-mm × 30-cm analytical column that contains 10-µm packing L1. The flow rate is about 1 mL per minute. Chromatograph the Resolution solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.9 for clotrimazole related compound A and 1.0 for clotrimazole; and the resolution, R, between clotrimazole related compound A and clotrimazole is not less than 1.2. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the relative retention times are about 1.0 for clotrimazole and 1.5 for testosterone propionate; and the relative standard deviation for replicate injections is not more than 2.0%.