(proe jes' ter one).
» Progesterone contains not less than 97.0 percent and not more than 103.0 percent of C21H30O2, calculated on the dried basis.
Packaging and storage Preserve in tight, light-resistant containers. Store at 25, excursions permitted between 15 and 30.
USP Reference standards 11
B: Ultraviolet Absorption 197U
Solution: 10 µg per mL.
Melting range 741: between 126 and 131. It may exist also in a polymorphic modification, melting at about 121.
Specific rotation 781S: between +175 and +183.
Test solution: 20 mg per mL, in dioxane.
Loss on drying 731 Dry it in vacuum over silica gel for 4 hours: it loses not more than 0.5% of its weight.
Mobile phase Prepare a filtered and degassed mixture of water and isopropyl alcohol (72:28). Make adjustments if necessary (see System Suitability under Chromatography 621).
Internal standard solution Transfer about 66 mg of methyltestosterone to a 10-mL volumetric flask, add dilute alcohol (85 in 100) to volume, and mix.
Standard preparation Dissolve an accurately weighed quantity of USP Progesterone RS in dilute alcohol (85 in 100) to obtain a solution having a known concentration of about 2.5 mg per mL. Transfer 4.0 mL of this solution to a 10-mL volumetric flask, add 1.0 mL of Internal standard solution, then add dilute alcohol (85 in 100) to volume, and mix to obtain a solution having a known concentration of about 1 mg of USP Progesterone RS per mL.
Assay preparation Transfer about 10 mg of Progesterone, accurately weighed, to a 10-mL volumetric flask, add 1.0 mL of Internal standard solution, then add dilute alcohol (85 in 100) to volume, and mix.
Chromatographic system (see Chromatography 621) The liquid chromatograph is equipped with a 254-nm detector and a 4-mm × 30-cm column that contains 10-µm packing L1. The flow rate is about 1.5 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the resolution, R, between the analyte and internal standard peaks is not less than 3.5; and the relative standard deviation for replicate injections is not more than 1.5%.
Procedure Separately inject equal volumes (5 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. The relative retention times are about 2.0 for progesterone and 1.0 for methyltestosterone. Calculate the quantity, in mg, of C21H30O2 in the portion of Progesterone taken by the formula:
10C(RU / RS)in which C is the concentration, in mg per mL, of USP Progesterone 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 4432Pharmacopeial Forum: Volume No. 29(5) Page 1566