Phensuximide
(fen sux' i mide).
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189.212,5-Pyrrolidinedione, 1-methyl-3-phenyl-, (±)-.
(±)-N-Methyl-2-phenylsuccinimide
[86-34-0].» Phensuximide contains not less than 97.0 percent and not more than 103.0 percent of C11H11NO2, calculated on the anhydrous basis.
Packaging and storage—
Preserve in tight containers.
USP Reference standards 
11
—
11—
USP Phensuximide RS 
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Identification—
Melting range, Class I 741:
between 68
and 74.
741:
between 68 and 74.
Water, Method I 921:
not more than 1.0%.
921:
not more than 1.0%.
Residue on ignition 281:
not more than 0.5%.
281:
not more than 0.5%.
Limit of cyanide—
Dissolve 1.0 g in 10 mL of warm alcohol, and add 3 drops of ferrous sulfate TS, 1 mL of 1 N sodium hydroxide, and a few drops of ferric chloride TS. Warm gently, and finally acidify with 2 N sulfuric acid: no blue precipitate or blue color is formed within 15 minutes.
Ordinary impurities 466—
466—
Test solution:
200 mg of phensuximide per mL in methylene chloride.
Standard solutions:
1.0, 2.0, and 4.0 mg per mL in methylene chloride.
Application volume:
5 µL.
Eluant:
a mixture of ethyl acetate and hexanes (1:1).
Visualization:
6.
Assay—
Transfer about 200 mg of Phensuximide, accurately weighed, to a 50-mL volumetric flask. Dissolve in 40 mL of alcohol, dilute with alcohol to volume, and mix. Transfer 5.0 mL of this solution to a 50-mL volumetric flask, dilute with alcohol to volume, and mix. Concomitantly determine the absorbances of this solution and of a Standard solution of USP Phensuximide RS, in the same medium having a known concentration of about 400 µg per mL, in 1-cm cells at the wavelength of maximum absorbance at about 258 nm, with a suitable spectrophotometer, using alcohol as the blank. Calculate the quantity, in mg, of C11H11NO2 in the Phensuximide taken by the formula:
0.5C(AU / AS)
in which C is the concentration, in µg per mL, of USP Phensuximide RS in the Standard solution, and AU and AS are the absorbances of the solution from Phensuximide and the Standard solution, respectively.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Hariram Ramanathan, M.S.
Associate Scientific Liaison 1-301-816-8313 |
(SM42010) Monographs - Small Molecules 4 |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 4291