Identification
Insert a pledget of fine glass wool into the base of a chromatographic tube of about 200×25mm.Mix 8.0mLof nitromethane with 7.0g of purified siliceous earth in a 150-mLbeaker until uniform,and transfer to the chromatographic tube,packing lightly with a suitable tamping rod.Pack a pledget of glass wool on the top of the column.Dilute 1mLof the Injection with
n-heptane to obtain a solution having a concentration of about 1mg of progesterone per mL.Transfer 4.0mLof this solution to the prepared column.Pass 300mLof
n-heptane through the column,discarding the first 120mLof the eluate.Collect the subsequent eluate in a 250-mLbeaker.Evaporate the solution under a stream of nitrogen on a steam bath to about 50mL,transfer to a 100-mLbeaker,and evaporate to dryness.Remove the last traces of
n-heptane by adding 1mLof methanol and again drying.Dry the specimen over silica gel for 4hours:the IRabsorption spectrum of a potassium bromide dispersion of the residue so obtained exhibits maxima only at the same wavelengths as that of a similar preparation of
USP Progesterone RS.
Assay
Mobile phase
Prepare a degassed mixture of alcohol and water (11:9).Make adjustments if necessary (see
System Suitability under
Chromatography á621ñ).
Standard preparation
Dissolve an accurately weighed quantity of
USP Progesterone RSin 20mLof tetrahydrofuran,and dilute quantitatively,and stepwise if necessary,with alcohol to obtain a solution having a known concentration of about 0.08mg per mL.
Assay preparation
Transfer an accurately measured volume of Injection,equivalent to about 100mg of progesterone,to a 100-mLvolumetric flask,add 20mLof tetrahydrofuran to dissolve,and dilute with alcohol to volume.Transfer 8mLof this solution to a 100-mLvolumetric flask,dilute with alcohol to volume,and mix.
Chromatographic system(see Chromatography á621ñ)
The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×25-cm column that contains 5-µm packing L1.The flow rate is about 1mLper minute.The column temperature is maintained at about 40

.Chromatograph a sample of dimethyl sulfoxide,and identify the retention time,
ta,of this nonretarded compound to calculate the capacity factor,
k¢.Chromatograph the
Standard preparation,and record the peak responses as directed for
Procedure:the capacity factor,
k¢,for progesterone is not less than 2.0;the tailing factor is not more than 2.0;and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
Separately inject equal volumes (about 10µL)of the
Standard preparation and the
Assay preparation into the chromatograph,record the chromatograms,and measure the responses for the major peaks.
[NOTEThe run time for the
Assay preparation must be at least twice that of the
Standard preparation.
]Calculate the quantity,in mg,of progesterone (C
21H
30O
2)in each mLof Injection taken by the formula:
1250(C/V)(rU/rS),
in which
Cis the concentration,in mg per mL,of
USP Progesterone RSin the
Standard preparation;Vis the volume,in mL,of Injection taken;and
rUand
rSare the peak responses for progesterone obtained from the
Assay preparation and the
Standard preparation,respectively.