Betamethasone Valerate Lotion
» Betamethasone Valerate Lotion contains an amount of Betamethasone Valerate (C27H37FO6) equivalent to not less than 95.0 percent and not more than 115.0 percent of the labeled amount of betamethasone (C22H29FO5).
Packaging and storage Preserve in tight, light-resistant containers, and store at controlled room temperature.
Identification Mix an amount of Lotion, equivalent to about 5 mg of betamethasone, with a mixture of methanol and chloroform (2:1) to make 10 mL. Apply 20 µL of this solution and 20 µL of a Standard solution of USP Betamethasone Valerate RS in a mixture of methanol and chloroform (2:1) containing 0.6 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. Allow the spots to dry, and develop the chromatogram in a solvent system consisting of a mixture of chloroform and ethyl acetate (1:1), 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. View the spots under UV light: the RF value of the principal spot obtained from the test solution corresponds to that obtained from the Standard 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.
pH 791: between 4.0 and 6.0.
Mobile phase and Chromatographic systemProceed as directed in the Assay under Betamethasone Valerate.
Internal standard solution Transfer about 50 mg of beclomethasone dipropionate to a 25-mL volumetric flask, add chloroform to volume, and mix.
Standard preparation Transfer about 40 mg of USP Betamethasone Valerate RS, accurately weighed, to a 25-mL volumetric flask, add chloroform to volume, and mix. Pipet 2 mL of this solution into a 50-mL centrifuge tube, add 10 mL of 0.1 N hydrochloric acid, then add 2.0 mL of Internal standard solution. Insert the stopper into the tube, shake vigorously for about 2 minutes, and centrifuge to separate the phases. Using a syringe, transfer the lower, chloroform phase to a small stoppered vial. Evaporate the chloroform on a steam bath, at low heat, with the aid of a stream of nitrogen. Add 4.0 mL of a 1 in 1000 solution of glacial acetic acid in methanol, and swirl to dissolve the residue.
Assay preparation Transfer an accurately weighed portion of Lotion, equivalent to about 2.5 mg of betamethasone, to a stoppered, 50-mL centrifuge tube. Add 10.0 mL of 0.1 N hydrochloric acid, insert the stopper, and shake to disperse the specimen. Add 2.0 mL of chloroform and 2.0 mL of Internal standard solution, insert the stopper, and proceed as directed for Standard preparation, beginning with shake vigorously for about 2 minutes.
Procedure Proceed as directed for Procedure in the Assay under Betamethasone Valerate. Calculate the quantity, in mg, of betamethasone (C22H29FO5) in the portion of Lotion taken by the formula:
(392.46 / 476.59)(4C)(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.
Auxiliary Information Please check for your question in the FAQs before contacting USP.Chromatographic Column
USP32NF27 Page 1666Pharmacopeial Forum: Volume No. 30(2) Page 461
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.