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Padimate O
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C17H27NO2 277.40

Benzoic acid, 4-(dimethylamino)-, 2-ethylhexyl ester.
2-Ethylhexyl p-(dimethylamino)benzoate [21245-02-3].
» Padimate O contains not less than 97.0 percent and not more than 103.8 percent of C17H27NO2.
Packaging and storage— Preserve in tight, light-resistant containers.
Identification—
Solution: 5 µg per mL.
Medium: alcohol.
Absorptivities at 312 nm do not differ by more than 4.0%.
Specific gravity 841: between 0.990 and 1.000.
Refractive index 831: between 1.5390 and 1.5430.
Acid value 401: not more than 1.0.
Saponification value 401: between 195 and 215, reflux temperature being maintained for 4 hours.
Chromatographic purity—
Chromatographic system (see Chromatography 621)—The gas chromatograph is equipped with a flame-ionization detector and a 3-mm × 1.8-m stainless steel column packed with 10 percent liquid phase G9 on support S1A. The column temperature is programmed at a rate of 10 per minute from 150 to 250, then maintained at 250 for 10 minutes, and helium is used as the carrier gas.
Procedure— Chromatograph 2 µL of a 1 in 100 solution of Padimate O in chloroform: the response due to padimate O is not less than 98.0% of the sum of the responses on the chromatogram, exclusive of the chloroform peak.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Assay— Dissolve about 500 mg of Padimate O, accurately weighed, in 75 mL of acetic anhydride, and titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically. Each mL of 0.1 N perchloric acid is equivalent to 27.74 mg of C17H27NO2.
Auxiliary Information— Staff Liaison : Feiwen Mao, M.S., Senior Scientific Associate
Expert Committee : (MDOOD05) Monograph Development-Ophthalmics Oncologics and Dermatologicals
USP29–NF24 Page 1627
Phone Number : 1-301-816-8320