Quantity delivered per spray—
Prime the spray pump by delivering 10sprays into a fume hood.Accurately weigh the entire assembly,record the weight,and deliver 8more sprays into the hood.Again weigh the assembly,and record the weight.Calculate the quantity,in µg,of C
24H
31FO
6delivered per spray taken by the formula:
[(W1-W2)/8][A/D],
in which
W1and
W2are the first and second weights,respectively,in g;
Ais the quantity,in µg per mL,of C
24H
31FO
6found in the
Assay;and
Dis the density of Nasal Solution,in g per mL.The quantity delivered is between 17µg and 33µg per spray.
Assay—
Mobile phase—
Prepare a suitable degassed solution of water,acetonitrile,and glacial acetic acid (69:30:1to 64:35:1).Adjust the ratio as necessary to obtain suitable chromatographic performance.
Internal standard solution—
Dissolve norethindrone in acetonitrile to obtain a solution containing about 300µg per mL.
Standard preparation—
Dissolve an accurately weighed quantity of
USP Flunisolide RSin a mixture of acetonitrile and
Mobile phase(1:1)to obtain a solution having a known concentration of about 250µg per mL.Transfer 1.0mLof this solution,and 1.0mLof
Internal standard solution,by means of “to contain”pipets,to a 50-mLvolumetric flask.Rinse the pipets with
Mobile phase,adding the rinsings to the flask,dilute with
Mobile phaseto volume,and mix.The final concentration of
USP Flunisolide RSis about 5µg per mL.
Assay preparation—
Transfer an accurately measured volume of Nasal Solution,equivalent to about 250µg of flunisolide,to a 50-mLvolumetric flask,and add 1.0mLof Internal standard solutionby means of “to contain”pipets.Rinse the pipets with Mobile phase,adding the rinsing to the flask,dilute with Mobile phaseto volume,and mix.
Chromatographic system
(see
Chromatography á621ñ)—The liquid chromatograph is equipped with a 254-nm detector and a 4-mm ×25-cm column that contains 5-to 10-µm packing L1.The flow rate is about 2mLper minute.Chromatograph the
Standard preparation,and record the peak responses as directed for
Procedure:the resolution,
R,between the analyte and the internal standard is not less than 5.0;and the relative standard deviation for replicate injections is not more than 1.5%.
Procedure—
Separately inject equal volumes (about 50µL)of the
Standard preparationand the
Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.The relative retention times are about 0.6for flunisolide and 1.0for norethindrone.Calculate the quantity,in mg,of C
24H
31FO
6in each mLof the Nasal Solution taken by the formula:
(434.51/443.51)(50C/V)(RU/RS),
in which 434.51and 443.51are the molecular weights of C
24H
31FO
6and C
24H
31FO
6·½H
2O,respectively;
Cis the concentration,in mg per mL,of
USP Flunisolide RSin the
Standard preparation;Vis the volume,in mL,of Nasal Solution taken;and
RUand
RSare the peak response ratios of the flunisolide peak and the norethindrone peak obtained from the
Assay preparationand the
Standard preparation,respectively.