Octisalate
C15H22O3 250.33
2-Ethylhexyl salicylate.
Benzoic acid,2-hydroxy-,2-ethylhexyl ester [118-60-5].
»Octisalate contains not less than 95.0percent and not more than 105.0percent of C15H22O3.
Packaging and storage— Preserve in tight containers.
USP Reference standards á11ñ— USP Octisalate RS.
Identification—
B:Ultraviolet Absorption á197Uñ—
Solution: 5.0µg per mL.
Medium: alcohol.
Absorptivities,calculated on the as-is basis,do not differ by more than 3.0%.
Specific gravity á841ñ: between 1.011and 1.016.
Refractive index á831ñ: between 1.500and 1.503at 20.
Acidity— Transfer 50mLof alcohol to a suitable container,add 1mLof phenol red TS,and add sufficient 0.1Nsodium hydroxide to obtain a persistent pink color.Transfer 50mLof this solution to a suitable container,add about 5.0mLof Octisalate,accurately measured,mix,and titrate with 0.1Nsodium hydroxide:not more than 0.2mLof 0.1Nsodium hydroxide per mLof Octisalate is required for neutralization.
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 preparation,as prepared 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 Octisalate 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 Octisalate RSin tert-butyl methyl ether,and dilute quantitatively,and stepwise if necessary,with tert-butyl methyl ether to obtain a solution having a known concentration of about 20.0mg per mL.
Assay preparation— Transfer about 2g of Octisalate,accurately weighed,to a 100-mLvolumetric flask,dilute with tert-butyl methyl ether to volume,and mix.
Chromatographic system (see Chromatography á621ñ)— The gas chromatograph is equipped with a flame-ionization detector and a 0.32-mm ×25-m column coated with a 0.1-µm film of phase G1.The carrier gas is helium,flowing at a rate of about 6mLper minute.The chromatograph is programmed as follows.Initially the temperature of the column is equilibrated at 60,then the temperature is increased at a rate of 8per minute to 240,and is maintained at 240for 10minutes.The injection port temperature is maintained at 240,and the detector temperature is maintained at 260.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the resolution,R,between octisalate 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 preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C15H22O3in the portion of Octisalate taken by the formula:
100C(rU/rS),
in which Cis the concentration,in mg per mL,of USP Octisalate RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(PA6)Pharmaceutical Analysis 6
USP28–NF23Page 1412
Pharmacopeial Forum:Volume No.30(3)Page 904
Phone Number:1-301-816-8389