2565 cefoxitin injection2564-头孢辛蛋白注射.pdfVIP

2564Cefoxitin/OfficialMonographsUSP35

Testsolution:10mgpermL,inmethanol.toapHof7.1±0.1,dilutewithwatertomake1000mL,and

Crystallinity〈695〉:meetstherequirements.mix.Filterthroughamembranefilterof1µmorfinerporosity.

pH〈791〉:between4.2and7.0,inasolutioncontaining100Standardpreparation—Dissolveanaccuratelyweighedquan-

mgpermL.tityofUSPCefoxitinRSinPhosphatebuffertoobtainasolution

Water,MethodI〈921〉:notmorethan1.0%,amixtureofhavingaknownconcentrationofabout0.3mgpermL.

ethyleneglycolandpyridine(3:1)beingusedinplaceofmeth-[NOTE—Sonicate,ifnecessary,todissolvethespecimen.]Use

thissolutionwithin5hours.

anolinthetitrationvessel.

Heavymetals,MethodII〈231〉:0.002%.Assaypreparation—Transferabout150mgofCefoxitinSo-

dium,accuratelyweighed,toa500-mLvolumetricflask,dis-

Limitofacetoneandmethanol—solveinanddilutewithPhosphatebuffertovolume,andmix.

Standardpreparation—Transfer5.0mLofacetonetoa1000-Usethissolutionwithin5hours.

mLvolumetricflask,dilutewithwatertovolume,andmix(Solu-Chromatographicsystem(seeChromatography〈621〉)—The

tionA).Transfer5.0mLof