» Prednicarbate Cream contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of prednicarbate (C27H36O8). It may contain a suitable preservative.
Packaging and storage Preserve in tight, light-resistant containers, and store at controlled room temperature.
USP Reference standards 11
USP Prednicarbate RS .
USP Prednicarbate Related Compound A RS .
USP Prednicarbate Related Compound B RS .
USP Prednicarbate Related Compound C RS .
Identification The retention time of the prednicarbate peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
Consistency At room temperature, a string of Cream having a length of 2 cm retains its shape on a glass plate for at least 10 minutes. It can be spread easily and has no visible lumps.
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. The total aerobic bacterial count does not exceed 100 cfu per g.
Minimum fill 755: meets the requirements.
pH 791: between 3.5 and 5.0, in a solution prepared in the following manner. Add 15 mL of boiling water to 3.5 g of Cream in a 50-mL centrifuge tube, and shake vigorously until an emulsion is formed. Loosen the cap, and place in a steam bath for 5 minutes. Centrifuge the hot solution. After cooling to room temperature, collect the lower aqueous solution in a glass tube, and determine the pH.
Solution A, Solution B, Mobile phase, Solution 1, Solution 2, and Resolution solution Prepare as directed in the Assay.
Standard stock solution Prepare as directed for Standard stock preparation in the Assay.
Standard solution Prepare as directed for Standard preparation in the Assay.
System sensitivity solution Dilute 1.0 mL of the Standard solution with dehydrated alcohol to 50.0 mL. Dilute 1.0 mL of the solution thus obtained with Solution A to 20.0 mL.
Test solution Prepare as directed for the Assay preparation.
Chromatographic system Proceed as directed in the Assay. Chromatograph the System sensitivity solution: the signal-to-noise ratio is not less than 3. Chromatograph the Resolution solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.57 for prednicarbate related compound B, 0.64 for prednicarbate related compound C, 1.0 for prednicarbate, and 1.04 for prednicarbate related compound A.
Procedure Inject a volume (about 60 µL) of the Test solution into the chromatograph, record the chromatogram, and measure the peak responses. Calculate the percentage of each related compound and unknown impurity in the portion of Cream taken by the formula:
100(ri / rs)in which ri is the peak response for each individual impurity obtained from the Test solution, and rs is the sum of the peak responses obtained from the Test solution: not more than 2.0% of prednicarbate related compound B and not more than 2.0% of prednicarbate related compound C is found; not more than 0.5% of any individual related compound is found; and not more than 5.0% of total related compounds is found.
Solution A Prepare a 0.01 M solution of monobasic potassium phosphate in water.
Solution B Prepare a mixture of acetonitrile and dehydrated alcohol (2:1).
Mobile phase Use variable mixtures of Solution A and Solution B as directed for Chromatographic system. Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard stock preparation Dissolve an accurately weighed quantity of USP Prednicarbate RS in dehydrated alcohol, and dilute quantitatively, and stepwise if necessary, with dehydrated alcohol to obtain a solution having a known concentration of 0.3 mg per mL.
Standard preparation Transfer 10.0 mL of the Standard stock preparation to a 100-mL volumetric flask, add 15 mL of tetrahydrofuran and 30 mL of Solution B, and dilute with Solution A to volume.
Assay preparation Transfer an accurately weighed quantity of Cream, equivalent to about 3.0 mg of prednicarbate, to a 100-mL volumetric flask. Add 15 mL of tetrahydrofuran, shake vigorously, and allow to stand in an ultrasonic bath until the sample has dissolved. Add 20 mL of dehydrated alcohol, and shake vigorously. Add 20 mL of acetonitrile, and shake vigorously. Immediately dilute with Solution A to volume, and shake vigorously. Allow to stand in an ice bath for at least 15 minutes. Shake the samples vigorously, and pass through a folded paper filter. Pass the filtrate through a membrane filter of 0.45-µm porosity.
Solution 1 Prepare a solution containing 0.3 mg per mL each of USP Prednicarbate Related Compound B RS and USP Prednicarbate Related Compound C RS in dehydrated alcohol.
Solution 2 Transfer about 15 mg of USP Prednicarbate Related Compound A RS, accurately weighed, to a 50-mL volumetric flask; add 1.0 mL of Solution 1, and dilute with dehydrated alcohol to volume.
Resolution solution Transfer 10.0 mL of the Standard preparation to a volumetric flask; add 1.0 mL of Solution 2, 1 mL of tetrahydrofuran, and 2 mL of acetonitrile; and dilute with Solution A to 20.0 mL.
Chromatographic system (see Chromatography 621) The liquid chromatograph is equipped with a 243-nm detector and a 4.0-mm × 25-cm column that contains 5-µm packing L1. The column temperature is maintained at 40. The flow rate is about 1 mL per minute. The chromatograph is programmed as follows.
Procedure Separately inject equal volumes (about 60 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the peak responses. Calculate the quantity, in mg, of prednicarbate (C27H36O8) in each g of Cream taken by the formula:
100(C/W)(rU / rS)in which C is the concentration, in mg per mL, of USP Prednicarbate RS in the Standard preparation; W is the weight, in g, of Cream taken; and rU and rS are the prednicarbate peak responses 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 3366Pharmacopeial Forum: Volume No. 32(3) Page 819
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.