Oxybenzone
;)
Methanone,(2-hydroxy-4-methoxyphenyl)phenyl-.
2-Hydroxy-4-methoxybenzophenone [131-57-7].
»Oxybenzone contains not less than 97.0percent and not more than 103.0percent of C14H12O3,calculated on the dried basis.
Packaging and storage—
Preserve in tight,light-resistant containers.
Identification—
A:
Infrared Absorption á197Kñ.
Solution:
10µg per mL.
Medium:
methanol.
Absorptivities at 287nm,calculated on the dried basis,do not differ by more than 3.0%.
Congealing temperature á651ñ:
not lower than 62.0
.
.
Loss on drying á731ñ—
Dry it in vacuum at 40for 2hours:it loses not more than 2.0%of its weight.
for 2hours:it loses not more than 2.0%of its weight.
Assay—
Standard preparation—
Dissolve an accurately weighed quantity of USP Oxybenzone RSin methanol,and quantitatively dilute with methanol,if necessary,to obtain a solution having a known concentration of about 10µg per mL.
Assay preparation—
Dissolve about 100mg of Oxybenzone,accurately weighed,in methanol in a 100-mLvolumetric flask,dilute with methanol to volume,and mix.Agitate gently,if necessary,to hasten solution.Pipet 1mLof the solution so obtained into a second 100-mLvolumetric flask,dilute with methanol to volume,and mix.
Procedure—
Concomitantly determine the absorbances of the Assay preparationand the Standard preparationin 1-cm cells at the wavelength of maximum absorbance at about 287nm,with a suitable spectrophotometer,using methanol as the blank.Calculate the quantity,in mg,of C14H12O3in the portion of Oxybenzone taken by the formula:
10C(AU/AS),
in which Cis the concentration,in µg per mL,of USP Oxybenzone RSin the Standard preparation;and AUand ASare the absorbances of 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 1434
Pharmacopeial Forum:Volume No.27(3)Page 2572
Phone Number:1-301-816-8389