Chromatographic purity
Test solution
Use the Assay preparation.
Chromatographic system
Proceed as directed in the Assay.To evaluate the system suitability requirements,use the Standard preparationprepared as directed in the Assay.
Procedure
Inject a volume (about 1µL)of the
Test solutioninto the chromatograph,record the chromatogram,and measure all of the peak responses.Calculate the percentage of each impurity in the portion of Octocrylene taken by the formula:
100(ri/rs),
in which
riis the peak response for each impurity;and
rsis the sum of the responses of all the peaks:not more than 0.5%of any individual impurity is found;and not more than 2.0%of total impurities is found.
Assay
Standard preparation
Dissolve an accurately weighed quantity of
USP Octocrylene RSin acetone,and dilute quantitatively,and stepwise if necessary,with acetone to obtain a solution having a known concentration of about 21.0mg per mL.
Assay preparation
Transfer about 2.1g of Octocrylene,accurately weighed,to a 100-mLvolumetric flask,dilute with acetone to volume,and mix.
Chromatographic system(see Chromatography á621ñ)
The gas chromatograph is equipped with a flame-ionization detector and a 0.32-mm ×60-m column coated with a 0.25-µm film of G1.Helium is used as the carrier gas at a flow rate of about 6mLper minute.The chromatograph is programmed as follows.Initially the temperature of the column is equilibrated at 80

;upon injection,the temperature is increased at a rate of 4

per minute to 280

,and is held at 280

for 10minutes.The injection port temperature is maintained at 300

,and the detector temperature is maintained at 300

.Chromatograph the
Standard preparation,and record the peak responses as directed for
Procedure:the resolution,
R,between the octocrylene and any other peak is not less than 1.0;and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
Separately inject equal volumes (about 1µL)of the
Standard preparation and the
Assay preparation into the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C
24H
27NO
2in the portion of Octocrylene taken by the formula:
100C(rU/rS),
in which
Cis the concentration,in mg per mL,of
USP Octocrylene RSin the
Standard preparation;and
rUand
rSare the peak responses obtained from the
Assay preparation and the
Standard preparation,respectively.