Packaging and storage—
Preserve in tight,single-dose
Containers for Injectionsas described under
Injections á1ñ,preferably of Type Iglass.Store in a refrigerator or at controlled room temperature.
Identification—
A:
Thin-Layer Chromatographic Identification Test á201ñ—
Test solution—
Pipet 1.0mLof Injection into a 10-mLvolumetric flask.Dilute with methanol to volume,and mix.
Standard solution:
1mg per mLin methanol.
Application volume:
20µL.
Developing solvent system—
Prepare a homogeneous mixture of acetone,chloroform,acetic acid,and water (6:2:1:1).Place mixture in a paper-lined chromatographic chamber,and equilibrate for about 15minutes prior to use.
Procedure—
Proceed as directed in the chapter,and then dry the plate under a current of warm air until completely dry.Place the plate into a second chromatographic chamber containing iodine crystals,and examine the plate:meets the requirements.
B:
The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that in the chromatogram of the Standard preparation,as obtained in the Assay.
Related compounds—
Diluent,Mobile phase,System suitability solution,Standard preparation,Column treatment,and Chromatographic system—
Proceed as directed in the Assay.
Test preparation—
Use the Assay preparation.
Procedure—
Separately inject equal volumes (about 10µL)of the
Standard preparationand the
Test preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg per mL,of fenoldopam related compound B(C
16H
16NO
3·CH
4SO
3)in the volume of Injection taken by the formula:
WSS(DS/DU)(rU/rS),
in which
WSis the weight,in mg,of
USP Fenoldopam Related Compound B RStaken;
Sis the conversion factor from the fenoldopam related compound Bto the free base (i.e.,0.77026);
DSand
DUare the dilution factors for the
Standard preparationand the
Test preparation,respectively (i.e.,0.0001and 0.02);and
rUand
rSare the average peak responses for fenoldopam related compound Bobtained from the
Test preparationand the
Standard preparation,respectively:not more than 0.6%is found.
Assay—
Diluent—
Dissolve about 1.38g of monobasic sodium phosphate monohydrate in 1Lof water,adjust with a phosphoric acid solution (1in 9)to a pHof 2.5,and mix.
Mobile phase—
Dissolve about 1.38g of monobasic sodium phosphate monohydrate and 1.88g of sodium hexanesulfonate in 1liter of water,adjust with a phosphoric acid solution (1in 9)to a pHof 2.5,and mix.Prepare a filtered and degassed mixture of this solution and methanol (67:33).Make adjustments if necessary (see
System Suitabilityunder
Chromatography á621ñ).
System suitability solution—
Transfer about 2.74mg of
USP Fenoldopam Related Compound B RS,accurately weighed,to a 100-mLvolumetric flask.Dissolve in and dilute with
Diluentto volume,and mix.
Standard preparation—
Transfer about 26.3mg of
USP Fenoldopam Mesylate RS,accurately weighed,to a 100-mLvolumetric flask,and dissolve in about 75mLof
Diluent.Add,by pipetting,1.0mLof the
System suitability solution,dilute with
Diluentto volume,and mix.
Assay preparation—
Accurately pipet about 0.5mLof Injection into a 25-mLvolumetric flask,dilute with Diluentto volume,and mix.
Column treatment—
[NOTE—This treatment is required for new columns only.]Pump a solution of cyclam (1in 1000)through the new column for about 3hours at a flow rate of about 1mLper minute,and then pump Mobile phasefor at least 2hours at the same flow rate.
Chromatographic system (see Chromatography á621ñ)—
The liquid chromatograph is equipped with a 225-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The flow rate is about 1.0mLper minute.Chromatograph the
System suitability solution,and record the peak responses as directed for
Procedure:the capacity factor,
k¢,is between 1and 3;the column efficiency is not less than 1800theoretical plates;and the tailing factor is not more than 2.5.Chromatograph the
Standard preparation,and record the peak responses as directed for
Procedure:the capacity factor,
k¢,is between 4and 6;the column efficiency is not less than 1800theoretical plates;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 preparationand the
Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg per mL,of fenoldopam mesylate (C
16H
16ClNO
3·CH
4SO
3)in the volume of Injection taken by the formula:
WSS(DS/DU)(rU/rS),
in which
WSis the weight,in mg,of
USP Fenoldopam Mesylate RStaken;
Sis the conversion factor from the fenoldopam mesylate to the free base (i.e.,0.7610);
DSand
DUare the dilution factors for the
Standard preparationand the
Assay preparation,respectively (i.e.,0.01and 0.02);and
rUand
rSare the fenoldopam peak responses obtained from the
Assay preparationand the
Standard preparation,respectively.