Betamethasone Valerate Cream
» Betamethasone Valerate Cream contains an amount of betamethasone valerate (C27H37FO6) equivalent to not less than 90.0 percent and not more than 110.0 percent of the labeled amount of betamethasone (C22H29FO5), in a suitable cream base.
Packaging and storage Preserve in collapsible tubes or in tight containers.
USP Reference standards 11
Identification Transfer an amount of Cream, equivalent to about 2 mg of betamethasone, to a separator, add 20 mL of water and 2 mL of dilute hydrochloric acid (1 in 120), and mix. Extract with four 50-mL portions of chloroform, and combine the extracts. Filter through a cotton pledget, previously layered over with anhydrous sodium sulfate. Evaporate the filtrates on a steam bath under a stream of dry nitrogen to dryness. Dissolve the residue in alcohol to obtain a solution containing about 1 mg per mL. Proceed as directed in Identification test B under Betamethasone Valerate, beginning with Apply 10 µL of this solution.
Microbial enumeration tests 61 and Tests for specified microorganisms 62 It meets the requirements of the tests for absence of Staphylococcus aureus and Pseudomonas aeruginosa.
Minimum fill 755: meets the requirements.
Mobile phase , Internal standard solution, Standard preparation, and Chromatographic systemProceed as directed in the Assay under Betamethasone Valerate.
Assay preparation Transfer an accurately weighed portion of Cream, equivalent to about 2.5 mg of betamethasone, to a 50-mL centrifuge tube. Add 10.0 mL of the Internal standard solution and 5.0 mL of a 1 in 1000 solution of glacial acetic acid in methanol. Insert the stopper into the tube, and place in a water bath held at 60 until the specimen melts. Remove from the bath, and shake vigorously until the specimen resolidifies. Repeat the heating and shaking two more times. Place the tube in an ice-methanol bath for 20 minutes, then centrifuge to separate the phases. Decant the clear supernatant into a suitable stoppered flask, and allow to warm to room temperature.
Procedure Proceed as directed for Procedure in the Assay under Betamethasone Valerate. Calculate the quantity, in mg, of C22H29FO5 in the portion of Cream taken by the formula:
(392.46 / 476.59)(15C)(RU / RS)in which 392.46 and 476.59 are the molecular weights of betamethasone and betamethasone valerate, respectively; C is the concentration, in mg per mL, of USP Betamethasone Valerate RS in the Standard preparation; and RU and RS are the peak response ratios obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 2347